# barrier coat



## BarryL (Aug 21, 2003)

Hello,

Now that spring is almost here, and the old bottom paint has been soda blasted off my boat, I need to decide on a barrier coat.

I plan on using PCA Gold Antifouling Paint with Irgarol from West Marine (please no comments on West Marine, their sale prices are very good), so I need a barrier coat that would be compatible with that paint.

What is the difference between Interlux Interprotect 2000E and Interprotect 3000? How does Petit Protect compare? 

I would be applying the barrier coat with a roller, if that means anything.

Barry


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## Freesail99 (Feb 13, 2006)

Barry, are you removing all the bottom paint first ?


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## sailingdog (Mar 19, 2006)

Freesail-

He had the boat bottom sodablasted...  So it's pretty safe to assume he removed the old bottom paint.

Barry-

The 2000E is what I'd recommend. The 3000 is a low-VOC emissions product developed for California's tighter emissions regulations IIRC, but is basically the same stuff, if a bit more expensive. It also has a lower working temperature than 2000E IIRC.


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## KeelHaulin (Mar 7, 2006)

A 5 gallon kit of MAS epoxy would also give excellent blister protection; you can apply it with a foam roller. Save any excess resin/hardener for future boat projects.


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## wchevron (Oct 19, 2007)

what is the difference between a barrier coat and anti-fouling paint?


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## T37Chef (Oct 9, 2006)

barrier coat prevents water intrusion into the fiberglass, anti fouling resit marine growth build up. Two completely different things.

Learn more here by clicking the info at the very top of the page...Pettit Marine Paints - About Pettit


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## wchevron (Oct 19, 2007)

so i'm assuming barrier coat first, then anti-fouling. i'm not trying to hijack the thread but rather than start another on the same topic, what would be a good barrier & anti-fouling for a cat 30 located in rhode island. most of my sailing would be in narragansett bay and surrounding area. i'm getting the bottom soda blasted the end of march.


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## Freesail99 (Feb 13, 2006)

KeelHaulin said:


> A 5 gallon kit of MAS epoxy would also give excellent blister protection; you can apply it with a foam roller. Save any excess resin/hardener for future boat projects.


5 gallons ??? Do you have any idea how much that is ? A gallon of epoxy and hardner would put at least 4 maybe 5 coats of epoxy on a 35 ft. boat.


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## sailingdog (Mar 19, 2006)

I don't think so Freesail. Paint will generally cover 400 sq. feet and epoxy covers a bit less generally. A 35' boat might be 30' LWL, and be 10' wide and 5' from water line to keel bottom... 30' x 10' is 300 sq. ft. I don't see it covering that four or five times.



Freesail99 said:


> 5 gallons ??? Do you have any idea how much that is ? A gallon of epoxy and hardner would put at least 4 maybe 5 coats of epoxy on a 35 ft. boat.


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## Freesail99 (Feb 13, 2006)

sailingdog said:


> I don't think so Freesail. Paint will generally cover 400 sq. feet and epoxy covers a bit less generally. A 35' boat might be 30' LWL, and be 10' wide and 5' from water line to keel bottom... 30' x 10' is 300 sq. ft. I don't see it covering that four or five times.


Sorry dog, this is first hand knowledge. One gallon put 5 coats with some left over on a 31 ft boat. Resin isn't paint.


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## SailorMitch (Nov 18, 2005)

While you may not need 5 gallons, I highly recommend MAS epoxy for the barrier coat. Easy to work with and it gives great results. check it out here Epoxy - MAS Epoxies: Home - Fiberglass Resins, Hardeners, Glues, Adhesives - Repair and Build Boats & Other Marine, Repair Cars & Automotive, Do Woodworking, Sport & Recreation, and other applications. Call them with questions; they are most helpful.

To answer the other question about a good barrier coat and then anti-fouling, here is what I did a couple of years ago on my Pearson 33, which had about 3 dozen blisters. Ground out the blisters in the fall and let them dry over the winter. In the spring checked the hull with a moisture meter and all was well on that front. I then applied 6 coats of MAS, one coat of black Pettit Trinidad paint (hard paint) and then 2 coats of of blue Pettit Ultima SR ablative paint. That has lasted me two years -- will have to apply a fresh coat of the ablative this spring. If I sand down to the black layer, I know to stop sanding so that I won't damage the barrier coat.


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## T37Chef (Oct 9, 2006)

Hey Steve, time to start getting ready eh...I'll be down most of the week of March 24th, see you there I'm sure


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## SailorMitch (Nov 18, 2005)

Chef -- Sounds like a plan. I hope to start in earnest late this week and have the bottom finished next week. Not that much to do on it. I still have a number of little projects to handle of course. I can't wait!


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## sailingdog (Mar 19, 2006)

If you're talking about one gallon of hardener, then you're talking three gallons of final epoxy... I'm talking about what one gallon of epoxy, in the case of MAS epoxies, 2/3 of a gallon of resin and 1/3 of a gallon of hardener.



Freesail99 said:


> Sorry dog, this is first hand knowledge. One gallon put 5 coats with some left over on a 31 ft boat. Resin isn't paint.


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## Freesail99 (Feb 13, 2006)

I will check my log at the boat, to be sure. I know I purchased 2 gallons plus hardner of Mas epoxy. I fiberglassed and epoxy coated my rudder, did the barrier coat, tabbed inside of the boat and still have epoxy left over.


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## saildork (Feb 20, 2007)

Hey guys, I have 2 gallons of West Systems 105. Is this comparable to the other barrier coatings mentioned here? Is it safe to assume that I'll get several coats per gallon on the bottom of a 22 foot boat?

Pat Lindsay
'Stargazer'


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## sailingdog (Mar 19, 2006)

Freesail-

If you bought two-gallons of resin, that would be three gallons final volume...so yes, you could coat the bottom of a 35' boat with that and get four or five coats and still have a good deal left over... I was saying that ONE GALLON of mixed epoxy wouldn't do it. 

Saildork-

Yes, you'll probably get two-to-three coats out of that. Personally, I'd rather use the Interprotect 2000E. I think it is more osmosis resistant than the regular epoxy and much easier to apply properly, since the IP2000E is available in two colors, making putting multiple coats of it on very easy... even if you have to move boatstands.


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## KeelHaulin (Mar 7, 2006)

sailingdog said:


> Freesail-
> 
> If you bought two-gallons of resin, that would be three gallons final volume...so yes, you could coat the bottom of a 35' boat with that and get four or five coats and still have a good deal left over... I was saying that ONE GALLON of mixed epoxy wouldn't do it.
> 
> ...


For my boat (30' LWL/41'LOA) it took about 5.5 gallons (mixed) to put 7 coats of epoxy on. The rated displacement of the boat is 18,000 lbs so I'm sure that the wetted area is a fair bit higher than most 30'LWL boats.

I suggested ~5 gallons; but it could be a bit less. I don't think it would take less than 3 gallons; but it could depending on the surface area.

On the issue of using West System; don't. The reason is because WS resin/hardener is not non-blushing. It leaves an oily residue on the surface after hardening which must be washed/scrubbed off between coats. Since you would have to allow the epoxy to cure (tack-free) before washing the process would be incredibly slow and you won't get chemical bonding between the coats. Call West System and verify this; they might have a non-blushing hardener or procedure that can prevent you from doing this process.

Whatever resin/hardener you choose make sure it is the "non-blushing" type. I used a 6 gallon epoxy resin kit from John Greer; worked as advertised. You allow the epoxy to cure to the point where it is tacky to the touch; then apply the next coat. You can paint it on with the same speed as doing the Interlux or Pettit; it's a bit more messy because epoxy is not as viscous (likes to drip and will run if you put paint it on too thick).

I don't think Interlux or Pettit is any better. I think a 100% solids epoxy will give you the most osmosis protection; but Interlux/Pettit is a bit more user-friendly. Both systems operate on building a sufficient layer of epoxy solids so that water cannot penetrate to the hull.

*With both systems (Paint or Epoxy) be sure and use an Organic Vapor Respirator; gloves, coveralls. The volumes of epoxy you are working with is much greater than when potting deck fittings, etc. and you are spreading it over a large surface area. The result is lots of epoxy amine vapour in the working proximity of the boat.*


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## sailingdog (Mar 19, 2006)

Actually, the barrier coat specific coatings, like Interprotect and Petit Protect have additives that are supposed to help increase their resistance to osmosis. MAS sells a barrier coating additive as well IIRC.


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## KeelHaulin (Mar 7, 2006)

INTERLUX said:


> InterProtect is unique among epoxies because it has Micro-Plates®, a protective barrier within its film to slow down water permeation. Technically, InterProtect Micro-Plates provide millions of overlapping microscopic plates that create a barrier similar to shingles on a roof.


I don't buy it... First of all it says "slow down water penetration"; does not say it stops it. Second; the shingles on a roof analogy is incorrect because your roof is not immersed in water. Water penetration via your hull is due to *diffusion*. Lamellar surfaces in a matrix are not diffusion-proof. It may slow the diffusion rate but it can't stop it. Those micro-plates are epoxy solids; which you get 100% of when you use a 100% epoxy resin/hardener system. The comparision that Interlux is making is between epoxy-based bottom paints; not between their system and the MAS epoxy procedure.

Don't see any "Osmosis Additive" on the MAS website; could you provide a link? 2 years ago when I talked to the owner of MAS at Strictly Sail Pacific he said that epoxy resin at the correct film thickness is 100% impervious to water with no additives needed.


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## sailingdog (Mar 19, 2006)

Keelhaulin—

It was West Systems not Mas Epoxies.


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## Freesail99 (Feb 13, 2006)

KeelHaulin said:


> I don't buy it... First of all it says "slow down water penetration"; does not say it stops it. Second; the shingles on a roof analogy is incorrect because your roof is not immersed in water. Water penetration via your hull is due to *diffusion*. Lamellar surfaces in a matrix are not diffusion-proof. It may slow the diffusion rate but it can't stop it. Those micro-plates are epoxy solids; which you get 100% of when you use a 100% epoxy resin/hardener system. The comparision that Interlux is making is between epoxy-based bottom paints; not between their system and the MAS epoxy procedure.
> 
> Don't see any "Osmosis Additive" on the MAS website; could you provide a link? 2 years ago when I talked to the owner of MAS at Strictly Sail Pacific he said that epoxy resin at the correct film thickness is 100% impervious to water with no additives needed.


I Couldn't agree more about the epoxy resin vs. epoxy paint statement. Makes no sense to me how a paint could offer anywhere near the same protection as epoxy resin.

I also spoke to the owner of Mas epoxy at a Stricley Sail show in Philly and was told the same thing.


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## Belizean (Mar 4, 2008)

*Info request*

Hi guys, I am very interested in learning more about the barrier coat, as I am in the process of bottom painting my new (second hand) St. Francis Cat. From what I gather you need to strip off all the old bottom paint, but do you apply the interprotect 2000E or the MAS Expoxy directly to the gel coat? How many coats do you recommend? Do you then apply anti fouling paint on top of the barrier coat? I am learning and appreciate all the info.


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## Freesail99 (Feb 13, 2006)

Belizean said:


> Hi guys, I am very interested in learning more about the barrier coat, as I am in the process of bottom painting my new (second hand) St. Francis Cat. From what I gather you need to strip off all the old bottom paint, but do you apply the interprotect 2000E or the MAS Expoxy directly to the gel coat? How many coats do you recommend? Do you then apply anti fouling paint on top of the barrier coat? I am learning and appreciate all the info.


Yes, strip off all the bottom paint and apply 4 to 6 coats of Mas Epoxy to the gelcoat. Then you can bottom paint over that.


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## KeelHaulin (Mar 7, 2006)

Belizean said:


> From what I gather you need to strip off all the old bottom paint, but do you apply the interprotect 2000E or the MAS Expoxy directly to the gel coat? How many coats do you recommend? Do you then apply anti fouling paint on top of the barrier coat? I am learning and appreciate all the info.


Yes; you strip the hull down to gel-coat. Some prefer to strip the gelcoat off in addition but it is not necessary since the barrier coat you will apply -should- be impervious to water. After you removed the old paint you then need to be sure the hull is sufficiently dry (use of a good moisture meter) and free of blisters (grind out any blisters, power-wash the hull several times, re-fair the ground-out blisters). Power washing will help wash out salt and any residual styrene in the blister "cavities"; it will not affect overall dryness of the fiberglass if you are in a dry climate. The drying out process can take from 2-6 months depending on how wet the FRP is and how dry the climate is that you are in.

When you are finished fairing and the hull is dry you apply the barrier coat and then follow with topcoats of anti-fouling paint. For MAS epoxy you are looking for 6-8 coats of epoxy IIRC to get the correct film thickness. For Interlux/Pettit I don't know how many coats you need.


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## Freesail99 (Feb 13, 2006)

The owner of Mas epoxy recommended that I use there Flag epoxy to barrier coat the bottom of my boat. He also said to apply 4 coats. Watch for runs as they can be a ***** to remove once they dry.


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## sailingdog (Mar 19, 2006)

For Interlux's Interprotect 2000E, you'll generally want four coats.


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## Belizean (Mar 4, 2008)

*Add'l info*

With regard to preparation, do you tape off the boot stripe with the blue masking tape just as if you were painting the bottom?


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## Freesail99 (Feb 13, 2006)

Yes tape the boot stripe before painting.


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## saildork (Feb 20, 2007)

Sailingdog, Keelhaulin,
Thanks for your advise. I've sent an email to West Systems with the concerns about their product that you stated. I'll let you know what I find out. Incidentally, the quantity of West that I have is 2 gallons of WS 105 resin and slightly less than 2 quarts of WS 206 hardener. These are mixed using the two pumps West provides so you can't mix them in the wrong proportions.

Pat Lindsay
"Stargazer"


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## Freesail99 (Feb 13, 2006)

Only mix what you can apply in 15 or 20 minutes or before it sets up. Warmer days mean shorter set up times. Wear latex gloves.


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## sailingdog (Mar 19, 2006)

Mix small quantities so it doesn't kick before you can apply it. Flat wide containers, like a roller tray are better than narrower taller containers, since a wide flat container will kick more slowly. 

It is very important that you don't re-use the containers, since partially cured or kicked epoxy will kick off a new batch prematurely. Use a new or fresh container for each batch. 

I would recommend nitrile gloves over latex. Some people can have a severe reaction to latex gloves.

Wear a full face mask respirator, since it will be more comfortable than goggles and a half-mask. Get the disposable covers for the full face mask so you don't damage the plastic of the face mask.


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## SailorMitch (Nov 18, 2005)

Belizean said:


> With regard to preparation, do you tape off the boot stripe with the blue masking tape just as if you were painting the bottom?


Actually, if you are using epoxy, use plain electrical tape and NOT masking tape. The epoxy will not stick to the electrical tape so it comes off much easier and you don't have a problem of the blue tape being epoxied onto the hull. That is another tip I got by calling the MAS guys when I was doing my research.

All this applies to using MAS epoxy -- it's what i used to barrier coat my boat so I know it worked for me.

As for pans for the rollers, buy two plastic ones and rotate their use. When the leftover epoxy cures in the first one it's easy to break it out and you have a fresh pan to use while the second pan cures.

Do use MAS because they now have the blush-free formulation. Even the old formula I used didn't develop the amine blush if you recoated at first opportunity. When your thumb nail can just make a dent, it's OK to recoat. What happens is that each coat fully cures together so you have one thick coat and not 6 separate ones.

Check the MAS mixing ratio because I think it's 2-1. So it's easy to mix a quart or so at a time in a big marked container you can buy at Home Despot. You don't need to go crazy with the frigging hand pumps that way.

WEST sells a separate barrier coat additive. I also talked to the MAS guys about whether I could add that to their product and they said sure if I wanted to waste my money. they said it's totally unnecessary with MAS, and I gathered they also thought it was a waste of money even with WEST, other than putting $$$ it WEST's pockets.


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## saildork (Feb 20, 2007)

Great advice from everybody. I received a reply from Gougeon Bros. (West Systems) on the question of their blushing epoxy. According to West, I will achieve a chemical bond by applying the 2nd and subsequent coats when I can make a mark with my fingernail in the not-yet-cured epoxy of the previous coat. If I allow it to cure, then I must wash and sand before applying the next coat (as Keelhaulin stated), which will produce a mechanical bond, not a chemical one.
By the way, someone mentioned painting before full cure of the barrier coat, thus producing a chemical bond between the paint and the epoxy. Is that true or did I hear wrong? Also, must you wear a respirator mask if you are working outdoors (ie. good ventilation)?

Pat
Stargazer


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## KeelHaulin (Mar 7, 2006)

The directions on the MAS website states that you should wait until full cure to paint (5-7 days). For an epoxy that will blush; you would then have to wash the surface and possibly give it a scuff sanding. You might call MAS and ask them if their non-blushing hardener is compatible with the West System resin.

When I painted the epoxy on I waited until the epoxy had cured to the point where it was tacky (not fully cured) before putting the next epoxy coat on. When I was finished with the epoxy coating I painted on one coat of Pettit Barrier Coat paint as a tie-coat. I did the Pettit coat a day after the epoxy cured; I did not wait a week.


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## sailingdog (Mar 19, 2006)

I wouldn't recommend mixing epoxy components from different manufacturers. First off, the mixing ratios are different. MAS uses a two-parts resin to one part hardener, and West uses four or five parts resin to one part hardener. That alone tells me it is unlikely that they'll be compatible. 

As for painting before the epoxy is dry...it really depends on what kind of paint your using. I was using a modified hard epoxy paint, and putting it over an epoxy barrier coat was recommended by both the manufacturer of the paint and the barrier coating... If you're using an ablative or a different paint that I did, which I am pretty sure is the case...YMMV.


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## epoxymoron (Mar 6, 2008)

*Misconceptions about blisters, barrier coats, and materials*

Hello to everyone,

I'll begin with a full disclosure statement - I am a tech advisor and chemist with WEST SYSTEM epoxy products. We did receive e-mails that directed us to this forum on the related subjects of blisters, barrier coats, epoxy and blush, as mentioned in this thread. Generally we don't get involved in forums for a multitude of reasons, but since our product has been specifically named I will take some time to respond.

In different threads than this particular one, the issue of why blisters form was debated. I will not go there except to say that we have a manual that explains it very well, 002-650 Gelcoat Blisters: Diagnosis, Repair, and Prevention. Contact us if you would like a copy. 866-937-8797 toll free.

As far as using WEST SYSTEM for barrier coating - there are literally 1000's of boats who have followed our recommendations and used our products over the last 40 years to successfully apply their barrier coats - including my own 1981 Pearson Flyer.

In order to keep this post relatively short I'm going to address a couple misconceptions that have appeared here point by point.

1. Epoxy forms an excellent water barrier - as good as it gets to be sure, but contrary to what the owners at MAS tell anybody NO EPOXY IS 100% WATERPROOF! To say otherwise is irresponsible.

2. Any epoxy system that uses amines in the hardener has the potential to blush...period. That said, some amines are more prone to blushing than others and this is the formulators science. Blush is a surface phenomena that occurs when CO2 in the air reacts with the amines at the epoxy/air interface forming a mixture of carbamate/carbonate salts. It forms preferentially in the presence of moisture - as in high relative humidity. It is water soluble and is easily removed with as little effort as wiping with wet paper towels. Since sanding a fully cured epoxy surface is required for any kind of overcoat, whether it's more epoxy or paints and varnish, wet sanding is simple, cleaner, and kills two birds with one stone. For the record, WEST SYSTEM 207 hardener is as low a blushing system as any product on the market - including MAS.

3. WEST SYSTEM epoxy is a full solids formulation and provides excellent water exclusion as dispensed. The 422 Barrier Coat additive is a proprietary blend of materials that are mainly flat platelets which serve to augment the chemical barrier provided by the epoxy by adding a physical barrier to water transmission. Our testing has proven that the additive improves moisture exclusion by about 5% over an identical thickness of epoxy only. It also provides a color change (grey).

4. Our testing has shown that a barrier coat with a minimum thickness of 20 mils is necessary to provide effective moisture resistance. Applying the epoxy with a thin foam roller cover and tipping yields about 4 mils/coat indicating 5 coats would be necessary to reach the 20 mil recommendation. My father and I applied 6 coats of WEST SYSTEM 105/206 with the 422 additive in the last 2 coats, mainly for the color change to let me know how far I've sanded in the future, in one day (about 7 - 8 hrs. work). We then wet sanded to prep for bottom paint and used VC 17 anti-fouling. I sometimes get small blisters under the cradle pads while on the hard and they are easily dealt with in the spring.

I'm not about to disrespect any of our competitors products, but felt it necessary to address some of the misconceptions being spread in this forum regarding epoxy barrier coats in general and our product specifically. We have a full time tech staff to answer questions and can be reached at the toll free number above M-F 8:00 to 17:00 EST.

Fair winds to all,

Bruce Niederer
Tech Advisor/Chemist
West System Epoxy Products


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## KeelHaulin (Mar 7, 2006)

sailingdog said:


> I wouldn't recommend mixing epoxy components from different manufacturers. First off, the mixing ratios are different. MAS uses a two-parts resin to one part hardener, and West uses four or five parts resin to one part hardener. That alone tells me it is unlikely that they'll be compatible.


Re-read my post 'dog; I suggested _*calling MAS to confirm*_ if they were cross-compatible. IME you -can- use a different hardener brand because the resin base is -somewhat- non-unique among epoxy companies. The jgreer resin worked with both their 2:1 ratio hardener and West 205 fast hardener at the 5:1 hardener ratio. I used the West hardener for small projects with the left-over resin from the barrier coat. To quote John Greer:



jgreer.com said:


> *Q. Can I use your resin with "WEST System" hardeners?*
> _*A.* They probably wouldn't appreciate it, but yes, my resin works fine with their hardeners. We probably all buy from the same manufacturers._





epoxymoron said:


> Epoxy forms an excellent water barrier - as good as it gets to be sure, but contrary to what the owners at MAS tell anybody NO EPOXY IS 100% WATERPROOF! To say otherwise is irresponsible.... Our testing has shown that a barrier coat with a minimum thickness of 20 mils is necessary to provide effective moisture resistance.


OK... What is the typical diffusion rate of water through standard (no additive) epoxy? In what general time frame would you expect to see the return of blisters on a hull that was barrier coated with your epoxy system? What is "effective moisture resistance", can you quantify this statement with some numbers?



epoxymoron said:


> Since sanding a fully cured epoxy surface is required for any kind of overcoat, whether it's more epoxy or paints and varnish, wet sanding is simple, cleaner, and kills two birds with one stone. For the record, WEST SYSTEM 207 hardener is as low a blushing system as any product on the market - including MAS.


IIRC MAS website states that no sanding is required before overcoat _(of the MAS-system)_; the paint will bond directly to their non-blushing epoxy. Is 207 cycloaliphatic? I thought that was the determining factor as to wether the epoxy produced _any_ amine blush or not.

If WS has a method that works for you; great. I was trying to point out that you can run into trouble with amine blush (as was presented to me at Strictly Sail by the MAS guy). It makes no difference to me what you use (MAS, WEST, jgreer.com, ETC). As I said before; the Interlux or Pettit systems are a bit more user-friendly in terms of application. Unless a study is done by Practical Sailor or someone to determine relative performance we will never know which product is "best" (aside from various people marketing you their "glop").


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## epoxymoron (Mar 6, 2008)

*Response to Keel Haulin*

There is no expected time frame for blisters to return. There are too many variables to ever make such a blanket statement. We do publish our test data and you can find the numbers you're looking for in the Gelcoat Blister manual I mentioned. I am happy to provide anyone who would like a copy with one. If you prefer to believe that one epoxy is 100% waterproof and another isn't that's fine - but the science doesn't support that conclusion.

I'm also not about to discuss the specifics of our formulations but, yes, large molecules like cycloalphatic amines are much less prone to blushing - as I mentioned. But any reactive amine hydrogen exposed to the air can react with the CO2. But epoxy formulation is a give and take exercise - cycloaliphatics are less likely to blush, but they are also very slow curing. 207 is very low blush with a reasonable through cure speed so the project can move ahead without waiting for a complete cure. You mentioned that MAS recommends waiting 5 -7 days before painting. At 70 degrees you will be able to paint over 207 after an over night cure.

Our testing has shown that the MAS claim that their epoxy is non-blush is more marketing than science, although it is very low blushing to be sure. If anyone wants to paint directly onto an un-sanded, shiny cured epoxy surface I say go for it! I wouldn't recommend it and I certainly wouldn't do so if the project were mine.


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## KeelHaulin (Mar 7, 2006)

epoxymoron said:


> If you prefer to believe that one epoxy is 100% waterproof and another isn't that's fine - but the science doesn't support that conclusion.


I don't... I always was skeptical about all of the claims that barrier coating will prevent moisture penetration 100%. I was wondering what the Do is for a typical epoxy to get an idea of how much "waterproofing" it will provide.


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## SailorMitch (Nov 18, 2005)

Bruce,

Thanks for your comments. Since I am the guy pushing MAS, I want to add that neither MAS nor I ever said their epoxy was 100 percent waterproof. I think their website does have some percentage of moisture absorption or some such thing, which is very low but obvioulsy shows it's not totally waterproof.

I have mentioned in previous threads on here about barrier coating (a very popular topic) that when I did my boat, the spring of 2005 I think it was, there were 2 other guys barrier coating their boats at the same time. Each of us used something different. One guy used WEST, I used MAS, and the other guy used one of the paint deals, but some industrial brand he said he got from a friend. I talked to the guy who used WEST just last fall, and his bottom is doing fine. Haven't seen the other guy to talk to.

What I also have said on other threads is that all the systems seem to work. It comes down to personal preference.

Just got back from the marina working on my boat, and the bottom continues to be in nice shape. The MAS has done well for me. But thanks again for setting the record straight. It's appreciated.


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## T37Chef (Oct 9, 2006)

Spring of 2006 I did some blister repair work on my boat. I used West System 105/209 (its was hot that week) with the 407 Low-Density Filler for filling blister voids. With the recommendation of the marina I also tried Pettit Protect Filler, a vinylester product I believe. I didn't care for it, mixing it nor sanding it, I preferred the WS with the filler for sure.

For a barrier coat I used the Pettit Protect. It was easy to work with and I used a WS foam roller for application. I applied 7 coats, maybe excessive but I was on a roll, pardon the pun. Before the last coat was cured, about 2 hours (if memory serves me right) I applied my first Anti-fouling Ablative paint, Pettit Ultima SR in Black, followed by two coats in Blue.

The boat was stored in the water for the last two winters, but at last pull, October 2007 for a quick power wash and zinc replacement, there was no sign of any blisters. I'll see in two weeks when I have it pulled for spring cleaning how well its holding up.

Since there is no black paint showing, after almost two years, I intend to do a light sanding this year and apply a fresh coat, I may try Micron 66 or whatever PS found as their best choice. BTW, I was not impressed with the Pettit Ultima SR for the Chesapeake Bay.

FYI...I rented this sanding unit from the yard, with the vacuum attachment and absolutely loved the thing. 









Festool - Pneumatic Tools, Carpentry, Workshop Tools


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## epoxymoron (Mar 6, 2008)

*It's a big enough world...*

for more than one brand of epoxy. Absolutely.

Thanks Sailor Mitch for your comments. My original post was directed more at comments made in this and other similar threads by folks participating in the forum. Since a customer told us about the forum, and we spend an awful lot of time and money disseminating proper application information, it was worth spending a few minutes to add my (our) 2 cents worth.


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## SailorMitch (Nov 18, 2005)

Bruce,

I know you folks are very easy to reach to proivde good information about your products. So are the folks at MAS, Pettit, Interlux -- any place you call you will get a good, direct response. That's great! So I always find it painful when someone comes on here asking us regulars questions about a product, when all they have to do is go to that company's website or call the tech support people and GET THE RIGHT INFORMATION. I even put the MAS link in a quick place I can go to because I post it here so often.

In reading back through all this, I do want to provide you one tidbit about my experience with MAS -- about drying time. I did let the hull dry 5 days before applying bottom paint. But I still had the areas under the jack stands to do. The timing for my scheduled launch was such that I had about a day and a half to apply 6 coats of epoxy and 3 coats of bottom paint to those 4 areas. No 5 days just for the epoxy to dry.

It's been 3 years now and those 4 spots are holding up just fine. No blisters, no lifting, no nothing. Funny how it often seems to work that way.

And how did I get onto MAS to begin with? Knew a professional wood worker who also made and taught kayak/canoe making from kits. He was big on it, so I tried it and liked it. No, I do not own stock in the company.

Thanks for showing up here. Industry folks show up regularly on Sailing Anarchy's forums, and it's good to have you here. Thanks again for your information.


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## camaraderie (May 22, 2002)

Bruce..thanks for your input AND conduct on this thread! We welcome mfrs. who can answer questions and correct misconceptions about their products on the forum. Feel free to chime in anytime you think something would benefit for a fuller explanation or clarification. Welcome aboard!


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## TSOJOURNER (Dec 16, 1999)

*A related question*

Found some bottom pox on my US Yacht 18 when I pulled it in Nov. Bought Don Casey's repair book in case I decided to get ambitious and redo the bottom so I could continue to dock it, rather than trailering it this year. So, Dom suggests that the gelcoat be sanded off below the waterline using 40 grit paper, then a barrier coat and antifouling paint. No mention of redoing the gelcoat. Probably gonna try it. So, do I need to replace the gelcoat, or just put on the barrier coat and bottom paint?

Thanks and Fair Winds


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## sailingdog (Mar 19, 2006)

Unless the bottom is clearly and badly blistered over a significant area with osmotic blisters, I wouldn't recommend sanding off all the gelcoat. I'd pop open the blisters—wear eye protection when doing this since the liquid in osmotic blisters is generally under pressure. If the blisters are wet, let the hull dry out. Then sand out the damaged area. If the damage extends into the fiberglass, rather than just the gelcoat, add some fiberglass cloth, otherwise fill with thickened epoxy and sand fair.


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## camaraderie (May 22, 2002)

Piper...no gelcoat required if you do as planned.


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## TSOJOURNER (Dec 16, 1999)

I agree with sailingdog in the process. We are doing the hull of a ChrisCraft 380 right now and had to remove blisters covering the entire hull. The only thing I would add is saturating the blisters with denatured alcohol (pure grain alcohol is better but it is not available everywhere and you may be tempted to drink it, producing a sloppy job over time) after opening them, then let them dry. The alcohol displaces the moisture in the blisters and promotes drying, It appears to clean the cavities as well, promoting better bonding of the epoxy. And the importance of using protective glove cannot be exaggerated. I can't remember if it was the hardener or base (hardener I think), I'm not allergic to much, but that stuff burned and then iched and just didn't want to stop. Not fun!!!!!


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## sailingdog (Mar 19, 2006)

One other reason I recommend leaving the gelcoat unless the boat has a very severe osmosis blistering problem is that with 40 grit it is pretty easy to go through the gelcoat and actually damage the underlying fiberglass.


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## TSOJOURNER (Dec 16, 1999)

I fully agree, not to mention that sanding the blisters is a horrendous job (especially lying under a powerboat) and sanding off the gelcoat on the entire hull may be enough to make someone scrap the entire job before its done. BTW, Black and Decker makes a dragster style sander that is great for getting into tight corners. Don't misunderstand, I don't like B&D tools but they're the only ones I know of to make this design. The switch isn't sealed and get loaded requiring removal, cleaning and rebuilding. I recommend taping plastic over it if anyone uses one. Oh yea, they're cheap too and you can get 30 or 35 grit making the job go a damn site faster. One other thing, the fluid in blisters can be caustic so protect yourself.


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## sailingdog (Mar 19, 2006)

Yes, you'll want the full tyvek bunny suit with full face mask if you're going to be doing this...


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## TSOJOURNER (Dec 16, 1999)

and good respirator, copper laden bottom paint dust mixed with shredded fiberglass can have a lasting impression on your lungs. Plus you can't appreciate the full discomfort of the job without your face sweating like a stuffed pig and your breathing restricted.


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## sailingdog (Mar 19, 2006)

The full face mask includes a respirator, and is generally, IMHO, far more comfortable than goggles and a half-mask ever will be. BTW, if you don't wear the bunny suit hood....wear earplugs... you don't want this stuff in your ears.



bob chaisson said:


> and good respirator, copper laden bottom paint dust mixed with shredded fiberglass can have a lasting impression on your lungs. Plus you can't appreciate the full discomfort of the job without your face sweating like a stuffed pig and your breathing restricted.


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## TSOJOURNER (Dec 16, 1999)

*Thanks Guys*

The blisters are really small and spread over large areas of the bottom, so I think it would be impractical to treat them each individually( I could do it, but it probably would take a year...). There are no HUGE blisters that can easily be punctured, ground out etc. ( Too bad... that sounds easier). So, my thinking is this: I could do the bottom , and then dock the boat( it's a fresh water lake that gets warm and scummy); trailer it ( Mast steps really easily, but there's WORK involved) and ignore the blisters; OR, ignore the blisters, dock the boat let the bottom rot and buy a new boat when it does. Problem is, I like my boat....
Any ideas or suggestions will be appreciated.
Fair winds to you.


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## T37Chef (Oct 9, 2006)

Remove all the old bottom paint, soda blasting would open most of the smaller ones up. Clean every few days over a few weeks on months and let dry. Grind out the big ones and fill and fair the entire bottom. Barrier coat and bottom paint and you'll be able to sell it or enjoy it for many more years.


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## TSOJOURNER (Dec 16, 1999)

T37Chef said:


> Remove all the old bottom paint, soda blasting would open most of the smaller ones up. Clean every few days over a few weeks on months and let dry. Grind out the big ones and fill and fair the entire bottom. Barrier coat and bottom paint and you'll be able to sell it or enjoy it for many more years.


Now there's sound advice, if I've ever heard it. I can't tell where your from but in VT and CT you can get 120+ proof grain alcohol for cleaning at the liquor store, it dosen't leave a residue. Bring small BBQ and 2 Litres of anything (to mix with cleaner). After 1 hr or so of grilling and drinking (opps I mean cleaning) you'll be a cleaning fool and the time will just fly by. Just be careful you don't grind a hole in her bottom (or the boats either).


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## TSOJOURNER (Dec 16, 1999)

Thanks gentlemen.

I'm in southern Illinois- you can buy grain ETOH here ( SIU ( Go Salukis)has a great recipe for wapatule- oops, that's from another day and time). Would lacquer thinner work just as well? it's cheaper.

Chef- what is soda blasting? I know Pepsi will eat steel, but I don't think this is what you meant. Is this an alternative to sanding? 

Fair Winds to you.


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## T37Chef (Oct 9, 2006)

*Sodablasting* is a process where sodium bicarbonate is applied against a surface using compressed air. It was first used to restore the Statue of Liberty.
Sodablasting is a non-destructive method for many applications in cleaning, paint stripping, automotive restoration, industrial equipment maintenance, rust removal, graffiti removal, molecular steel passivication against rust, oil removal by saponification and translocation, masonry cleaning and restoration, soot remediation, *boat hull cleaning*, food processing facilities and equipment.

Sodablasting - Wikipedia, the free encyclopedia


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## TSOJOURNER (Dec 16, 1999)

No, unfortunately, (or fortunately depending on your point of view). Lacquer thinner leaves a residue, as does anything other than grain alcohol but denatured alcohol comes close (but is not dual purposed - except on some remote Russian military bases and possibly certain parts of Appalachia). It is the most commonly used cleaner (although I believe multitasking has alot to be said for it).


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## sailingdog (Mar 19, 2006)

I'd second T37Chef's idea. Sodablasting would do an excellent job of opening up most of the small blisters while removing existing bottom paint and prepping the surface of the bottom of the boat. It's also reasonably priced in many areas. Several people on this site, including myself, have had their boats sodablasted in the last couple years. 

Acetone will also clean off the bottom of the boat, and may be a good alternative to grain alcohol. Be careful with either though, since both are quite flammable.


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## TSOJOURNER (Dec 16, 1999)

Acetone leaves a residue as well, more so that denatured alcohol. At a previous job, I had to clean special optics that read measurements of 1/2 of 1/1000 of an inch. The equipment manufacturer documents identified grain alcohol as the only fluid that didn't leave a residue. I'm sure for this purpose, denatured works fine.


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## TSOJOURNER (Dec 16, 1999)

Thanks Guys

Soda blasting sounds like the way to go

I never pass up an opportunity to betray my own stupidity. Now to find somebody down here who does this . This area is pretty close to "those" areas of appalachia, and unlike the winos in NYC who use italian bread to strain the wood alcohol, I think some folks drink it straight up here.

Thanks again and Fair Winds to you.


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## TSOJOURNER (Dec 16, 1999)

Hello all. I apologize for reviving a couple of week old thread on barrier coats but as I'm a couple of weeks away from applying one, I wanted to make sure I understood one point. How low of moisture reading do you need to have in order for a barrier coat to make sense? In this regard, I've read posts on other forums that suggest that most of the epoxy barrier coat manufucaturers recommend that the hull to be coated have such a low moisture reading that any hull that is 20 years or more old and spends six months in the water each year couldn't possibly meet their recommendations. In addition, these posts have stated that applying a barrier coat to a relatively dry hull (but one that has more moisture than recommended) is inviting a blister problem. 

Many thanks,

Mike


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## sailingdog (Mar 19, 2006)

Wolfmt-

I think it depends on whether the boat had a previous osmotic blistering problem and you're doing the barrier coat as part of a repair or whether the barrier coat is being done prophylactically. In the first case, I do believe you need to dry out the laminate, since it is saturated and that is what was causing the initial osmotic blistering problem to begin with. With a preventative coating...the hull and gelcoat are usually relatively dry to begin with, so don't generally require a long drying out period.


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## SailorMitch (Nov 18, 2005)

The answer in theory is that yes, the laminate should be "dry." The problem is measuring that accurately. I don't think most moisture readers commonly in use are all that accurate. At best they give you a range of comparison for your boat. One area is "dryer" than another area. Even then, you'd need to calibrate the meter with however the barrier coat manufacturer expresses "dryness".

When I barrier coated my boat I hauled it in Oct., punctured the blisters to let them drain over the winter, and then I took moisture readings the following March just before I applied the barrier coat. I used a meter borrowed from a friend, and it is a common one you see advertised all the time. The bottom was "dry" according to the meter so I went ahead with my project. The bottom still looks great. My boat was 17 years old when I applied the barrier coat.


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## TSOJOURNER (Dec 16, 1999)

Thanks sailingdog. In this case, the boat is approximately 30 years old. The bottom paint has been stripped down to gel coat and there were a handful of blisters (less than 20) that have been repaired. Otherwise the bottom is in great shape. The boat has been out of the water since September. The boat was surveyed in January and was described as dry but I don't have the specific moisture readings for the hull (the deck had a couple of moist spots for which I have specific moisture readings). What do you think?


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## sailingdog (Mar 19, 2006)

Wolf-

Not having the moisture readings and such... I would suggest you barrier coat it, if the previous blisters have been treated. Do you know if the previous blisters were osmotic or not???


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## TSOJOURNER (Dec 16, 1999)

This has been a pretty impressive and informative thread in re applying a barrier coat. I'll be rolling the bottom of my Cheoy Lee Luder's 36, probably this weekend and need to estimate the materials required.

The lwl is 25', beam is 10'3", draft is 5'3." What is the size of the area in suare feet? Or, said differently about how many gallons will I need to put on six coats? I am planning to use MAS resin and was thinking of using slow hardener. 

The weather in the Mattapoisset, MA area tends to the cool side, under 80 and likely in the low 70s for this time of the year.


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## sailingdog (Mar 19, 2006)

You're probably about 275 sq. ft of surface area or so... as a really rough guess. As for how many gallons it takes to barrier coat that, why don't you call up MAS Epoxies and ask them. I'm sure they're worked with people doing this previously.


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## TSOJOURNER (Dec 16, 1999)

sailingdog said:


> You're probably about 275 sq. ft of surface area or so... as a really rough guess. As for how many gallons it takes to barrier coat that, why don't you call up MAS Epoxies and ask them. I'm sure they're worked with people doing this previously.


Thanks, Dog, I have a call in to Tony, hit the voicemail, but will probably hear back from him shortly. I figured that there is probably some formula or rule of thumb for estimating the area. One post said a fellow had done his 40' boat with six gallons but his boat is much larger than mine.

I am kind of thinking that two gallons of resin and a gallon of hardener will get the job done. I may get three gallons or resin, a gallon of hardener and a spare 1/2 gallon of hardener, just in case, and if it is not needed I can take it back to Jamestown Dist. I understand that this material is pretty thin so a little bit will go a long way.

Any idea on how many rollers this job might take? I am planning to do the whole job in a 24 hour period. Also, someone mentioned using black electric tape instead of masking tape to edge the boot stripe, what do you think of that idea?

Thanks,
Bob


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## sailingdog (Mar 19, 2006)

Use the good 3m Blue masking tape.  Get lots of roller covers, trays and mixing containers. What I've found works fairly well for mixing is GladWare containers... and you can usually recycle them by popping out the hardened epoxy after it cures completely. 

The reason you need lots of roller covers, trays and mixing containers is that you need a fresh set for each batch of epoxy you mix up. If you re-use a container that has older epoxy it, it will cause the new batch to kick prematurely IIRC. If you buy the roller covers from Home Depot, rather than a marine supply store, they'll be cheaper and you can return the unopened packages of them that you didn't need to use.


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## Freesail99 (Feb 13, 2006)

I mixed about 16 oz. of epoxy up at a time and used a 6 inch foam roller to apply. I suggest the moment you finish applying that coat or part there of, epoxy, you pull the foam roller off the handle and wipe the handle down, or you'll never get the roller off or another one on. I used 3 bags of 6 rollers each to do my bottom.


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## SailorMitch (Nov 18, 2005)

AA3NK said:


> Thanks, Dog, I have a call in to Tony, hit the voicemail, but will probably hear back from him shortly. I figured that there is probably some formula or rule of thumb for estimating the area. One post said a fellow had done his 40' boat with six gallons but his boat is much larger than mine.
> 
> I am kind of thinking that two gallons of resin and a gallon of hardener will get the job done. I may get three gallons or resin, a gallon of hardener and a spare 1/2 gallon of hardener, just in case, and if it is not needed I can take it back to Jamestown Dist. I understand that this material is pretty thin so a little bit will go a long way.
> 
> ...


I'm probably the guy who suggested using black electrical tape, which is what MAS recommended to me.. the epoxy will stick to masking tape and may glue that tape to the hull, making for another clean-up job. epoxy will not stick to the electrical tape. but if you are calling MAS anyway ask them again.


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## craigtoo (Aug 17, 2007)

Don't let the blue masking tape stay on for long or it will be an absolute PAIN to remove. 

I left it on for a week once and that was a disaster. It removed some of my waterline as well...


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## sailingdog (Mar 19, 2006)

The trick is to remove the blue tape within a few hours of finishing up the barrier coating. The blue stuff has worked well for me on three different boats that were barrier coated, one with IP2000E, one with Epoxy and one with something else.


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## craigtoo (Aug 17, 2007)

Spot on SD. 

I applied 14 coats of epoxy.. so it took a while... (in the winter you have to wait for the right temp..)

After learning that lesson.. I peeled the tape and and reapplied after after every 2 coats (which is about 12 hours).


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## sailingdog (Mar 19, 2006)

BTW, it depends on which blue tape you use.... they make them in various grades. The one we used for my boat was the long term one and can be left on almost two months without much problem.


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## craigtoo (Aug 17, 2007)

Oh.

Mine was just blue... you always get the good stuff...


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## sailingdog (Mar 19, 2006)

Just FYI-

*Scotch-Blue™ Painter's Tape for Delicate Surfaces #2080 1 in x 60 yds (36 rls/cs)*

This tape removes cleanly without adhesive transfer or surface damage for up to 60 days, even in direct sunlight. It is a low-medium adhesion tape that is ideal for smooth, freshly painted surfaces, faux painting, wood floors and glass.


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## Freesail99 (Feb 13, 2006)

> I applied 14 coats of epoxy.. so it took a while... (in the winter you have to wait for the right temp..)


14 coats ! I am wondering, if the beam of your boat is now wider, lol 
That is a lot of epoxy.


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## craigtoo (Aug 17, 2007)

Well.. it was a complete new bottom.

Peeled then re-built. So it's just as thick as it was! 

Of course it took about a month to do.... but I am so far pleased with the results. The true test will be when I haul it this winter and inspect it.


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## TSOJOURNER (Dec 16, 1999)

First things first, you guys have been very helpful and informative, I feel like I am ready to move forward on the project and will do it entirely over a 24 hour period as soon as I can get down there. And, I am still going to use the MAS product.

I never got a return phone call from Tony. He doesn't owe me or have any duty or obligation to answer every low end user phone call he gets. I still don't know the answer as to how much I'll probably need and equally important, which catalyst to use in August. So, I'll get the slow stuff and pace myself. I am figuring on a total of three gallons of resin to do six coats. It mixes 2:1 so that ought to be beau coups product for a full keel 36 footer with 24' at the water line.

I'll make some pictures as the project comes along for future reference.


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## 02VETTE (Dec 12, 2008)

On the same theme,
I've scraped of the CSC off the bottom of a 3700 (because it was falling off anyway) and was debating weather to put on a barrier coat of 2000E. The gelcoat is vinylester am I wasting my time?

02


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## sailingdog (Mar 19, 2006)

If you're down to the bare gelcoat, there is really no good reason not to barrier coat.


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## T37Chef (Oct 9, 2006)

02VETTE said:


> On the same theme,
> I've scraped of the CSC off the bottom of a 3700 (because it was falling off anyway) and was debating weather to put on a barrier coat of 2000E. The gelcoat is vinylester am I wasting my time?
> 
> 02


Definitely do it, but be sure *ALL* the old paint is off. Post a pic if you can


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## 02VETTE (Dec 12, 2008)

Thanks,
There is still a bit more to go but will be sure to get it clean. I've read the recommend prep instructions and will need to sand after a solvent wash. Tartan doesn't like you sanding the vinylester but this boat is an '02 and is out of warranty so I feel this would be a good move to barrier coat. Will do my best to get some pics posted.
Regards


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## deniseO30 (Nov 27, 2006)

Last spring I paid one of the guys at my YC to sand the BC off and made sure I was the one working on the blisters that were under a 100 in number. But then who was counting? She's now sporting 5 coats of 2000E and I'm very happy with it! When we pulled the boat in the fall all the slime washed off and the WM generic bottom paint looked like the day we painted it on! Hard to tell in the pic but we faired the bottom where the so called encapsulated keel to hull joint is. It's still fair and unchanged so I guess the keel isn't falling off! I suggest any filling of dings or other blemishes are done with something other then pure white so you can see the repair. I had been using only West System products. So I must say using another epoxy product like Interlux's 2000E was a leap of faith and I'd also seen it applied to at least 3 catalina 30s. This is what she looked like after the sanding. We did not use anything less then 80 grit so the barrier coat would have a good bond mechanically as well as chemically.










Good luck on your project! system 3 is good stuff too! I used it on strip canoes long before I went to west systems.


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## BarryL (Aug 21, 2003)

Hey,

Barrier coat is a good thing, but it's a little more complicated than just "remove old paint, clean, apply barrier coat."

Depending on the particular barrier product you are using, there are all sorts of restrictions on when you can apply the barrier coat (temperature), how many coats of barrier you need, how much time you need to wait between applying the coats (and how long is too long), and finally, when you MUST apply the antifouling paint.

Note that most barrier coats are epoxy based, and epoxy tends to be slippery. Wait too long for the epoxy to dry and the antifouling may not stick to it.

Again, I used Pettit Protect and followed the instructions VERY carefully. I applied the bottom paint when the last barrier coat was still tacky. I had excellent adhesion of bottom paint. The antifouling didn't work as well as I hoped (a fair amount of growth) so I will try a different type next year, but the paint stuck well to the barrier coat, and I have no blisters.

Barry


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## sailordave (Jun 26, 2001)

*Well, I for one...*

am glad this thread got resurrected. This has been a discussion item w/in my group for one of our boats. I personally have used WEST and MAS in the past for various projects and boatbuilding. I like them both although the MAS 2:1 ratio is more user friendly.

Thanks for all the helpful hints. (The electrical tape hint really does work too!)


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## TSOJOURNER (Dec 16, 1999)

*Blisters!*

Blisters have always been a problem for my hands. For the past few years I just sanded and repainted the bottom. I pulled the boat this fall to do a refit and decided to tackle the blisters (many). Blisters were only in the gel coat, not into the fiberglass. I was first planning to dig the blisters out, fill, and then heavy sand before barrier coat. Then it was suggested I soda blast, so I got prices for that. Then my surveyor suggested I peel the bottom and get rid of all the blisters. Glad he did. Peeling was cheaper than soda blasting and a whole lot easier than sanding. I still have to grind the areas the machine couldn't get to but all blisters are gone. Will be building up with epoxy and go from there. A lot of work to go but I got rid of all the blisters. Letting the bottom dry til weather allows for epoxy. Just my pennies worth.

David


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## jarcher (Jul 29, 2008)

This is a great thread...

I am taking the paint off my boat Sunday. It currently has Interlux micron ablative, and I'll use the Interlux stripper to remove it, down to bare gel coat. I'm doing this because the paint is in pretty bad shape anyhow, and I want to use the VC 17m Extra to replace it.

I am thinking of coating with Interlux VC TAR2, which needs 5 to 7 coats, before I do the 3 coats of VC 17m.

I am wondering if anyone has worked with VC TAR2 and if so, how was the experience? 

My thinking is that all the reputable products will do a good job and last a while, so I am trying to figure out which is the easiest


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## celenoglu (Dec 13, 2008)

It is always a good idea to measure the humidity of the hull before applying the barrier coat. If the humidty is high, barrier coating is not recommended.


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## tager (Nov 21, 2008)

Does gelcoat not work as a barrier coat?


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## jarcher (Jul 29, 2008)

celenoglu said:


> It is always a good idea to measure the humidity of the hull before applying the barrier coat. If the humidty is high, barrier coating is not recommended.


Yup, I was thinking about that. When I bought the boat last September the surveyor measured the hull at many points and said the moisture content was quite low. But, the boat has Interlux micron anti-fouling on it now, so maybe that messed his readings up. I'll measure again after the paint is stripped.


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## jarcher (Jul 29, 2008)

tager said:


> Does gelcoat not work as a barrier coat?


Well gel coat is a bit water permeable. The barrier coat is less so. This helps prevent against water getting in and causing blisters and other damage. This was discussed quite a bit earlier in this thread. It's a great thread, well worth reading from the top.


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## jarcher (Jul 29, 2008)

*WOW, this stuff is EXPENSIVE*

I may have to rethink this! This is going to cost a fortune!

Okay, so my 30 foot LOL boat is estimated to have 184 ft^2 to cover under the wateline.

If I want to use either Interlux VC Offshore or VC 17m Extra, the compatible barrier coat is VC Tar2.

VC Tar2 covers 460 ft^2 per gallon. Coats needed: from 5 to 7. So, 7 coats = 1,288 ft^2, which is 2.8 gallons or 11.2 quarts (it is only sold in quarts). 11 quartes = $517 + shipping!

And then there is the paint itself.

VC Offshore would need 3 coats, which needs 2.8 gallons. At $209 per gallon thats $627 bucks.

I think I'll look at more conventional barrier and anti-fouling options


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## T26Rich (Feb 7, 2009)

BarryL said:


> Hey,
> 
> Depending on the particular barrier product you are using, there are all sorts of restrictions on when you can apply the barrier coat (temperature), how many coats of barrier you need, how much time you need to wait between applying the coats (and how long is too long), and finally, when you MUST apply the antifouling paint.
> 
> Barry


How did you manage the jack stands with the interprotect and still have it sticky before applying the bottom paint? I have an extra set of jack stands that I've used quite well to get all of the bottom paint off. Now with the weather hopefully cooperating I can apply Interprotect 2000E barrier coat and paint. Advice much appreciated.


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## sailingdog (Mar 19, 2006)

I wrote this up a while back, and it can be used to allow you to properly "hotcoat" the bottom paint as well as properly barrier coating the bottom.



sailingdog said:


> Alternating the colors helps a lot with determining where you've painted, but it is also very useful for helping you coat the areas around the boat stands. For instance:
> 
> The first layer is gray, since the gelcoat is white, and you can paint right up to the boat stand pads. Then you paint a layer of white, and leave about a two-inch margin of gray paint around the pads... then paint a layer a gray and leave a four-inch margin around the pads or about two-inches of white and two inches of gray showing...and then finish with a layer of white-with a six-inch margin around the pads-with two inches of gray, two inches of white and two inches of gray.
> 
> ...


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## Maine Sail (Jan 6, 2003)

jarcher said:


> I may have to rethink this! This is going to cost a fortune!
> 
> Okay, so my 30 foot LOL boat is estimated to have 184 ft^2 to cover under the wateline.
> 
> ...


You call that a lot? I just wrote a check for 8K to have mine done! Unfortunately I have done four full bottom jobs and vowed to never, ever do another. While writing that check sucked it still felt good.. Original quote was 5k but I added a bunch of stuff as we went along like wrapping the keel to hull joint, removing all thru-hulls and barrier coating under them etc etc.. At $80.00 per hour it adds up quick. This is why the only things I pay for are Awlgrip work and now bottom jobs..


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## T26Rich (Feb 7, 2009)

sailingdog said:


> I wrote this up a while back, and it can be used to allow you to properly "hotcoat" the bottom paint as well as properly barrier coating the bottom.


If I under stand it, it takes two days then. First day for the main areas, second day for the jack stand areas after moving stands, unless its 90 degrees out all day.


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## Maine Sail (Jan 6, 2003)

T26Rich said:


> If I under stand it, it takes two days then. First day for the main areas, second day for the jack stand areas after moving stands, unless its 90 degrees out all day.


It's done in stages. IPK2E has a six month open window for hot coating IPK2E to itself but bottom paint must be done at thumbprint dry which can be tough on a large hull.

On my hull they barrier coated day one. Day two, after 24 hours, moved the stands and applied shrink wrap plastic to the heads and barrier coated a second coat. Day three, after 24 hours, moved stands back to original location barrier coated. For hot coating the paint they did the last pad spots after the two coats of paint had cured for two days then moved the stands and did barrier coat and paint hot coated at the pad spots. When all was said and done she had five coats of IPK2E and two coats of hot coated ablative copolymer paint. At 68 - 70 degrees it took two guys. One to get the last coat of barrier on and the otehr to follow shortly behind to begin hot coating paint. At 68-70 it kicks off in less than an hour to thumb print dry so you really need two people to do the last step right if it is near room temp.


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## T37Chef (Oct 9, 2006)

Maine...I think I see a spec of dirt on your hull...WTH is going on??????


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## sailingdog (Mar 19, 2006)

That's cause he didn't do the bottom job... he contracted it out...and they left the dirt there... 


T37Chef said:


> Maine...I think I see a spec of dirt on your hull...WTH is going on??????


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## trecksail (Dec 2, 2004)

*Bottoms*

Hello all,
Just read the entire thread and thought I'd toss in some personal experience. I work in a boat yard and do quite a bit of bottom stripping etc.
Hopefully this won't bring on more lawsuit crap here, but every boat that I have sanded down that had 2000 for a barrier coat had loads of blisters just under the 2000. Like the 2000 was letting water in but not letting it back out. I get in arguments with the other yard guys regularly about it as it's still the only barrier coat we seem to offer here. I get the inproper prep reply often but many of the boats come from many other yards. I couldn't fathom that everyone was doing it wrong so I re-read the directions on the 2000 can numerous times. For some reason, possibly it's just been added, I'd never noticed some small print that says to go to their website for their "full" tech sheat instructions if desired. I advise anyone considering 2000 to go to the site themselves and check it out. First of all, they require an initial coat of their own straight epoxy before the 2000, along with other pretty rigid steps to the point that I doubt any yard has ever followed, even if they'd somehow known the steps existed.

As far as major blister problems, I'd advise going with stripping the gellcoat. Gellcoat is 99% of the time polyester resin which is not as waterproof as epoxy resin. And the problem with blisters is that the water supposedly changes chemically when trapped in with resin to the point that it will almost never really dry out without incredible effort and months to years in a rediculously dry and warm environment. We've just trialed a new electric mechanical stripper and have to say it is the cat's meow. It's actually a paint stripper which is simular to a grinder but has 3 triangular blades which do the stripping. One guy took the entire bottom gellcoat off a 37 foot Pearson in about 6 hours. Damn near a perfect removal to the glass on his first time using the tool. It's called a paint shaver pro and came mounted on what seems to be a Hitachi grinder body. You can check it out at American International Tool Industries, Inc. LLC | Makers of the Paint Shaver Pro paint stripping, paint stripping tools, paint removal, paint removal tools, paint scrapers, lead paint removal, stripping lead paint, infrared paint heater. I'm not affiliated with em, but highly recomend it. Shaved to the glass quicker than even just sanding off the bottom paint alone. And it came with a vacume attatchment. Be prepared with ALOT of vacume bags but very little mess! Amazing tool.

Back to barrier coat. I will be going with straight West system epoxy on the Wanderer next winter. Just don't trust the whole microplatelet thing. How can millions of mechanic bonds to microplatelets be more impervious than a solid barrier completely chemically bonded to itself? Seems like a marketing gimmick to me. And as far as epoxies, I've seen MAS and can't say anything bad about them, but I absolutely love West System. I have never, ever heard anyone have West System fail. The only reason to me to even think about trying anything else is price, and these days there's just not enough difference in price to consider it. Hell, if all boats were built entirely out of West there wouldn't be a boat yard in business anywhere.


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