# OK, so I'm Sanding My Bottom...



## Squidd (Sep 26, 2011)

But I'm from the Midwest and not so sure what I'm looking at...(all we paint out here is houses barns and tractors...)

Is this supposed to be so "lumpy"...










Doesn't look like any "paint" I've ever seen before... It looks "thick"... like an 1/8" thick and like it was put on with a spatula and back brushed with a whisk broom...that's just the "Red" layer...










And it's "Soft" almost chalky or powdery...some of it flakes off (in the blistery ares and the "layered" areas.. and then the rest is stuck on tight...

Below that is a light blue/gray also "Thick" powdery layer...



















I think it had popped blisters as well and then the red went over that...

Below the Gray is a greenish chopped fiberglass layer that is hard...

The whole thing down to Glass is almost 1 1/4" thick...










But you can see some of the red also goes all the way down to the glass matt..

_So what do I got here and what do I do with it...??_

I'm thinking continue sanding all the blisters/bubbles down to the green glass matt and then fair and fill with some sort of epoxy/poly "filler"...?

Then fair the bulk of the bottom to smooth out the "lumps...

Prime (type) ??

Bottom paint...

What I'm looking for is advice on getting it to the "primed" stage...There's enough arguments/threads on bottom paint choices already...

Thanks in advance...


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## jfdubu (Jul 18, 2002)

Wow Squidd, it look s like you've opened a real can of worms. My guess it this boat as been filled and faired,, and fillled and faired,,, and filled and faired again, and not once was it done right. 

I couldn't begin to tell you all the steps but you have to get down to a firm foundation. I hope you got a good deal on the boat.


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## Squidd (Sep 26, 2011)

The "gel coat" if there is one is whats throwing me...

I would assume the ablative coat(s) <red> would be soft and when sanding I should "hit" a hard coat layer (gel coat) but it just kind of mixes and blends with the gray coat and then bango...glass matt...??

Here's a couple more shots...where you can see glass and depthe of "gray matter"



















Blisters aren't "watery" blisters more like air bubbles between layers...and then when they open, they kinda peel away at the edges to become open "sores"..

Some in the red just down to gray... and some in gray that were covered by red...

And a couple that went thru both layers down to glass matt


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## Faster (Sep 13, 2005)

Pretty cool pictures of the surface of the moon!!

What are you using for this job? Looks like a very aggressive abrader, I'm a little worried you're going too deep. Some of these spots look well into the laminate.

Huge fairing job ahead!


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## Squidd (Sep 26, 2011)

jfdubu said:


> Wow Squidd, it look s like you've opened a real can of worms. My guess it this boat as been filled and faired,, and fillled and faired,,, and filled and faired again, and not once was it done right.
> 
> I couldn't begin to tell you all the steps but you have to get down to a firm foundation. I hope you got a good deal on the boat.


Deal wise I'm doing OK... bought it at auction for under a grand, hauled it home for under a grand...and have it rigged and readied to sail for just a little over a grand (lottsa work on my part)....So depending on what the bottom takes I'll be on the water well under 4...

I'm not looking for a 30 year repair or "investment"...

I want to do it "well" and reasonably economical for now...I don't think I'll be going down to glass and re gelcoating the bottom, I just want to get it faired, waterproofed, hard coated and back in the water...


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## Squidd (Sep 26, 2011)

Faster said:


> Pretty cool pictures of the surface of the moon!!
> 
> What are you using for this job? Looks like a very aggressive abrader, I'm a little worried you're going too deep. Some of these spots look well into the laminate.
> 
> Huge fairing job ahead!


 60/80 grit in 5" random orbital...

There are some deep grooves in the glass but you can also see the red in grooves that were there before I got to it..


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## bljones (Oct 13, 2008)

Squidd,

Ditto what jfdub said.

If you want to be in the water this season, forget you saw what you saw, mix up some slightly thickened epoxy, slather it on the exposed mat, roll it out, mix up some fairing compound, slather it on, sand and shape it, cover it with some barrier coat, bottom paint and go. In the fall, soda blast it and spend the winter cleaning it up.


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## mitiempo (Sep 19, 2008)

Squidd

You don't have to re-gelcoat it. But you have to get rid of the bottom paint from the previous 3 decades or so to get any fairing material to stick to it. Apparently no previous owner bothered.

I don't think it would be very expensive - a lot of work though. 

After the bottom paint is gone, fill any dips with thickened epoxy, fair with epoxy mixed with low density filler, a coat or 2 of straight epoxy and then bottom paint.


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## mitiempo (Sep 19, 2008)

bljones said:


> Squidd,
> 
> Ditto what jfdub said.
> 
> If you want to be in the water this season, forget you saw what you saw, mix up some slightly thickened epoxy, slather it on the exposed mat, roll it out, mix up some fairing compound, slather it on, sand and shape it, cover it with some barrier coat, bottom paint and go. In the fall, soda blast it and spend the winter cleaning it up.


That's the quick fix.


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## MedSailor (Mar 30, 2008)

Since you're sanding that super toxic stuff, I assume that you have all 147 permits that are required and that you've conducted fish impact studies as well using EPA certified salmon psychiatrists....



MedSailor

PS That grey matter looks like the real fiberglass of your hull. Me thinks you went a little too deep there. Perhaps a lighter grit sandpaper would be better?


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## Frogwatch (Jan 22, 2011)

What you have is very thick old bottom paint (the red) and ground out blisters ( the craters). Remove most of the red stuff with your sander. Fill the craters and holes with epoxy mixed with low density plastic filler, put it on with a putty knife. Sand it smoothish, no neeed to be obsessive about this on an old boat. Put a layer of thin epoxy over the filled areas. Do not try to seal the boat with epoxy, it will not work. Then put on your bottom paint and go sailing.
Blister "repair" is almost always a waste of time, fixing something that isnt broken. Ignore any more blisters that are not broken open.


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## Squidd (Sep 26, 2011)

bljones said:


> Squidd,
> 
> Ditto what jfdub said.
> 
> If you want to be in the water this season, forget you saw what you saw, mix up some slightly thickened epoxy, slather it on the exposed mat, roll it out, mix up some fairing compound, slather it on, sand and shape it, cover it with some barrier coat, bottom paint and go. In the fall, soda blast it and spend the winter cleaning it up.


I think I'm in full agreement here...It's only a 5 month season at best up here so I want to get 'er wet and shake 'er out...

I have a buddy that can do the blasting and I have indoor work space to "do it right" when I have more time (and money) next fall...so that's the plan...

Now just need to come up with a plan to patch into what I have...

It's not quite as soft as Bondo, but it is a quite soft and powdery whatever it is...

I'm not grinding all that aggressively, just cleaning out the "divots"... like I said, you can see the red "top coat" in the bottom of the grooves on the lowest level..So that was done before I got there..

I just gotta fix it...


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## mitiempo (Sep 19, 2008)

Frogwatch said:


> What you have is very thick old bottom paint (the red) and ground out blisters ( the craters). Remove most of the red stuff with your sander. Fill the craters and holes with epoxy mixed with low density plastic filler, put it on with a putty knife.


I agree, but don't use a putty knife - you will be sanding until June.

Use a wide flexible piece of plastic, the wider the better. Used carefully there will not be much sanding required.


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## CalebD (Jan 11, 2008)

Brian is right about making a mold for the surface when applying 'putty'. Something like a thin plexiglass sheet can leave a nice fair surface or cut up a plastic milk gallon and use the smooth side for small patches. You will have to come up with a way (duct tape, dead men) of applying light pressure to your repair to hold the mold in place evenly. Even thin plywood (< 1/8" thick) can make a decent mold and bend to the shape of the hull. Any wood left on is easier to sand off then fiberglass/FRP.


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## mitiempo (Sep 19, 2008)

I wasn't exactly recommending that. I was just recommending using a wide flexible piece of plastic instead of a putty knife. The thickened epoxy should be mixed just thick enough that it doesn't run or sag. If you can fair the epoxy as you put it on over 12" or 16" width the sanding will be a lot less than if using a putty knife.


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## MedSailor (Mar 30, 2008)

Squidd said:


> I think I'm in full agreement here...It's only a 5 month season at best up here so I want to get 'er wet and shake 'er out...
> 
> I have a buddy that can do the blasting and I have indoor work space to "do it right" when I have more time (and money) next fall...so that's the plan...
> 
> ...


Sounds like a good plan so far, concentrate on sailing, do it right when you have the time.

As for a quick and dirty way to revitalize the bottom..... have you considered ironing it?

MedSailor


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## Squidd (Sep 26, 2011)

MedSailor said:


> Sounds like a good plan so far, concentrate on sailing, do it right when you have the time.
> 
> As for a quick and dirty way to revitalize the bottom..... have you considered ironing it?
> 
> MedSailor


Ouch, the Iron burns again...

That probably won't work, but I am open to constructive suggestions...

Along those same lines, I'm still not willing to toss it out and buy new...nor am I going to send it out and let someone else do it for me...


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## Barquito (Dec 5, 2007)

> Since you're sanding that super toxic stuff, I assume that you have all 147 permits that are required and that you've conducted fish impact studies as well using EPA certified salmon psychiatrists....


We tend not to have many environmental regulations in Wisconsin... less in the past 18 months... oops did I say that out loud?


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## Frogwatch (Jan 22, 2011)

I agree with the wide flexy plastic thingy. This is really an easy repair if you use epoxy, forget Bondo. Get some epoxy (you need about a qt) with those little metering pumps. Save a bunch of butter tubs for mixing it in. Get the reddish plastic low density microballoon filler. Get some of those cheap chip brushes from Wal Mart, get a bunch of em. Mix some epoxy unthickened and paint it in the cavities to seal them. Next, mix up some epoxy thickened with the filler and put it in the cavities using the plastic thingy to spread it to shape of the hull.

Something I'd try, tape wax paper over the craters on top of the epoxy. The wax paper does not stick to the epoxy and will give you a smooth surface.


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## Squidd (Sep 26, 2011)

Barquito said:


> > Since you're sanding that super toxic stuff, I assume that you have all 147 permits that are required and that you've conducted fish impact studies as well using EPA certified salmon psychiatrists....
> 
> 
> We tend not to have many environmental regulations in Wisconsin... less in the past 18 months... oops did I say that out loud?


I just filter that stuff threw my cigarette butts anyway...at least till they clog up...

Heck, cut my smoking in half...


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## Squidd (Sep 26, 2011)

Hull Blisters on Boats and Yachts - by David Pascoe, Marine Surveyor

After reading some of these commentaries, I'm left wondering if there is a "do it right" solution....

In which case whatever I do will be the correct responce...


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## CalebD (Jan 11, 2008)

Yes, Pascoe paints a fairly dim picture on blister repairing. Well worth reading all of that section before you attack your job.


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## mitiempo (Sep 19, 2008)

And a very practical article on blistering by Jan de Groot, a surveyor with decades of experience. Interesting point of view.
Sea Lake Yacht Sales (Kemah, TX)


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## Squidd (Sep 26, 2011)

Yep... The more I read up on it the beter I feel about it...



> After reading some of these commentaries, I'm left wondering if there is a "do it right" solution....
> 
> In which case whatever I do will be the correct responce <solution>...


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## Squidd (Sep 26, 2011)

Just finished up sanding... Feels like I've been sanding for a week...

Wait a second...I have been sanding for a week...

Anyway, after laying under this thing, staring at it day after day...It really doesn't look all that bad...Overall shape is still discernible just has a hundred or more "divots" to fill, so it shouldn't be too hard to "fair out" and get smooth...










After the 1/8" of ablative coating was sanded off, the resultant divots were only a 1/16" deep on average so not much filler will be required...










Worse one was the big one in the front (first page) but even that one is less than an 1/8" deep..










I think the late afternoon "shadows" were making it look worse than it is in the first couple photos...

Plan is to fill and fair with Fiberglass Marine Filler and then a coat of Polyester Resin overall, scuff sand and then hard biocide finish...


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## CalebD (Jan 11, 2008)

Squidd said:


> Just finished up sanding... Feels like I've been sanding for a week...
> 
> Wait a second...I have been sanding for a week...
> 
> ...


Can you remove that sea strainer and lightly sand that area too? I took mine off this year allowing me to paint under the strainer but I had to take out the 4 screws holding it in place.

The 3M Marine Filler is a vinyl-ester product but seems to be intended for what you plan on using it for.

Conventional wisdom has it that epoxy resins have better adhesion than polyester resin which is why people barrier coat with epoxy. However, David Pascoe doesn't seem to think that conventional wisdom knows very much about blister repair.

Your hull does not look so bad after your sanding so have at the next phase.
Good luck with your plan.


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## Squidd (Sep 26, 2011)

There was another cover/strainer over that sea strainer...(blue rectangle)...that I took off...

I think that bubble is part of the thru hull, But I can take another look...

Using Evercoat 574 Marine Fiberglass filler supposed to be for below water use...Don't know if that's different than 3M product.

As far as epoxy vs poly...sounds like there is no expert schedual for permenent repair of blisters so whatever I put on is going to fall off...or not...


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## deniseO30 (Nov 27, 2006)

Congrats on the job! I'd suggest one more thing to do before you start filling and fairing. Make sure large (and small) areas the remaining gel coat are not peeling, loose, or barely holding on. Good luck!


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## SloopJonB (Jun 6, 2011)

Frogwatch said:


> I agree with the wide flexy plastic thingy.


The wide, flexy thingy is called a *screed*. An old hand saw blade works well - just grind the teeth off so you have a flat edge.


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## deniseO30 (Nov 27, 2006)

I'd only use epoxy and epoxy mixed fillers myself, but I've been using the stuff for over 20 yrs. My son and I used to build strip canoes... glass and epoxy clear coated in and out. Even when we stopped that and started traditional boat building there was still plenty of things to use it on. Now on bigger boats it's amazing.. the barrier coat is like armor.. the bottom paint scrubs off from river debris but the barrier coat is untouched even from the mooring buoy scuffing it. 
just saying..


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## travlin-easy (Dec 24, 2010)

That's probably the worst looking bottom I've seen in 50 years--bar none. Squid, the first thing you want to do is get rid of that sander. The easiest and best thing I've come across for sanding a boat bottom is a tool used by sheet rock hangers for sanding spackle paste. It's a fairly coarse, stainless-steel screen fitted over a flat, cushioned pad attached to a relatively long handle. The screens and handle can be found at Home Depot, Lowes, etc..., the screens do an outstanding job, don't wear out quickly like sand paper, and you do the entire job wet. Just dip the head of the screen in a bucket of water, and scrub the bottom. The finish will be flat, smooth and ready to paint in just a couple hours. For some reason I thought everyone knew about this technique, but I guess I was wrong.

Good Luck,

Gary


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## Squidd (Sep 26, 2011)

I'll give the screen/pad a try to flatten things out on the next step when I fill and fair the bottom... I have the toolage here...

I don't think it would have worked on the ablative though, I needed the sander to "clean out" the divots without taking the whole hull down to fiberglass matt...

The divots were actually in the hull prior to ablative being applied as witnessed by the red ablative at the bottom of most of the "divots"... Looks like someone had ground out the blisters previously, but rather than fill just overcoated with the ablative...

Good news is there weren't any "new" blisters or soft spots forming in the 4-5 years the boat was in the water since the ablative was put on...

Here's an older photo from before I started, you can see the blister divots under the red ablative...


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## Minnewaska (Feb 21, 2010)

Squid,

I'm seeing red, white, blue and brown on your finished sanding. Lots of work, btw, nice job.

I assume the brown is where the blisters got into the mat. The red is remnants of the ablative, since you've referred to it. 

I'm confused by what the porous white stuff is? Previous filler? Is it secure enough to apply over again? What's the blue?


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## Squidd (Sep 26, 2011)

The blue on that later picture is where I took off a larger rectangular screen box that was covering the brass sea screen seen..But it too was "paint" over the gray/white porus stuff, it just hadn't been sanded down in a previous "redo"...

What the white/gray stuff is ...I don't know...but it's been on there for awhile...although in most places it sanded out and "flaired back" nicely and seems "tightly attached".. a couple places (first pictures) show "air bubbles" in the mix, but they sanded out to tight material as well..

The only "history" I know on the boat is the PO bought it in the water 5 years ago and never had it out.. so everything we're looking at has been soaking for 5 years ... and/or "redone" 5 or more years ago...

The blister/divot/craters were "pre-ablative" and as far as I can tell no new blister/loose spots/cankers have developed under the ablative coating...

Also looks like in a previous "redo"... someone drilled and spot filled the blisters with another "something" seen as the perfect "yellow" circle in some of the blister craters...










I believe they predate the preablative divot creation...

Quite the premordial "chemical soup" I need to cover...


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## PorFin (Sep 10, 2007)

Squid,

Couple of semi-educated guesses here:

o The beige colored repairs in your most recent post look to be made with resin thickened with West System Microlight filler. It could be either epoxy or poly resin, but I'd guess epoxy.

o The "white chalky" stuff is likely a poly filler (Bondo or an equivalent) with white cream hardener.


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## CapnBilll (Sep 9, 2006)

I would guess the yellow circles are some form of epoxy used to fill the early blisters.

I don't know how much time and money you want to spend on this, but you really dont want to kick the can down the road any more either. 

Once you get it as clean as you can epoxy can fix a lot of past sins. 

My opinion is if it doesn't leak, the surface is sealed, and the bottom is smooth after painting. You have a boat. 

Regelcoating the whole bottom may not be what you want to do right now.


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## Squidd (Sep 26, 2011)

Exactly...

My goal is to fill, fair, put a sealer/barrier coat on and biocide paint...

See what it looks like next spring and "maybe" in a couple years a total redo... 

But really it's a $3k boat...I'm not planning on putting $5k bottom job on it...


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## CapnBilll (Sep 9, 2006)

PorFin said:


> o The "white chalky" stuff is likely a poly filler (Bondo or an equivalent) with white cream hardener.


I've never had much sucess with that "stuff". My earliest memory of it is my uncle scraping it out of an old car repair to redo it.

The few times I've tried it, may have been from it sitting on the shelf of an auto parts store too long, but I got the same results.

Once the benzoyl peroxide cream, (yes the same stuff you put on zits), couldn't completly harden the resin leaving me with scraping out a mess the consistancy of silly putty mixed with bubble gum.

I've had good luck with polyurathane, and with polyester. I would skp the bondo.


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## PorFin (Sep 10, 2007)

CapnBilll said:


> I've had good luck with polyurathane, and with polyester. I would skp the bondo.


Agreed. I'm not suggesting Bondo as the filler to use -- there are far better products out there. Selecting a filler that's recommended for below the waterline use would be prudent.

The colors of body fillers are usually imparted by the hardener used. Bondo comes with a red cream hardener, hence the pinkish tinge of the properly mixed putty. Other body fillers come with different colored hardeners (blue and green seem pretty common), but the base filler is usually white or grey.


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## Sailormon6 (May 9, 2002)

If you'll look at the photo of the strainer, it is surrounded by white surface. I think that's your gelcoat. Everything on top of that surface is either old paint, or dirt or algae covered with old paint. I don't think most of the pits you are seeing are "boat pox." I think they are simply many layers of peeling paint. If you get all the red and brown and blue stuff off, eventually you'll get down to the white gelcoat, which is where you want to be. You don't want to remove the white gelcoat.

I wouldn't apply any filler to try to smooth it out, because I believe you'll be filling pits in old bottom paint and dirt, sealing them there forever. You have done a terrific amount of hard, nasty work, and smoothed out the original mess fairly well. My suggestion is that you apply one coat of ablative antifouling and enjoy sailing the boat for the summer, and then, next spring, have another go at it, and finish the job. After it's finally done, if you use no more than one coat of good quality ablative each year, you'll probably never have to strip it again. After you get rid of all that old paint, you'll be able to see whether there really are any osmotic blisters under it. At that time, you can decide whether you need to do anything about them.


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## SloopJonB (Jun 6, 2011)

CapnBilll said:


> Regelcoating the whole bottom may not be what you want to do right now.


Don't EVER bother with that. If & when you decide to do the bottom properly, get it soda blasted or sand & scrape it down to a good surface, fill the blister divots properly with thickened epoxy, fair it up with orbitals and longboards then coat it with Interprotect per the manufacturers directions.

Presto changeo - a racing bottom!


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## SloopJonB (Jun 6, 2011)

CapnBilll said:


> I've had good luck with polyurathane, and with polyester. I would skp the bondo.


Bondo and other auto body fillers ARE polyester. They shouldn't be used on boats as they will permit water absorption - use epoxy fillers only.


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## SloopJonB (Jun 6, 2011)

Sailormon6 said:


> If you'll look at the photo of the strainer, it is surrounded by white surface. I think that's your gelcoat. Everything on top of that surface is either old paint, or dirt or algae covered with old paint. I don't think most of the pits you are seeing are "boat pox." I think they are simply many layers of peeling paint. If you get all the red and brown and blue stuff off, eventually you'll get down to the white gelcoat, which is where you want to be. You don't want to remove the white gelcoat.
> 
> I wouldn't apply any filler to try to smooth it out, because I believe you'll be filling pits in old bottom paint and dirt, sealing them there forever. You have done a terrific amount of hard, nasty work, and smoothed out the original mess fairly well. My suggestion is that you apply one coat of ablative antifouling and enjoy sailing the boat for the summer, and then, next spring, have another go at it, and finish the job. After it's finally done, if you use no more than one coat of good quality ablative each year, you'll probably never have to strip it again. After you get rid of all that old paint, you'll be able to see whether there really are any osmotic blisters under it. At that time, you can decide whether you need to do anything about them.


Mon has it right - where there is bare glass showing, it is surrounded by white - almost certainly gelcoat. I would at least paint some epoxy resin over the bare glass that's showing before putting on bottom paint.


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## PorFin (Sep 10, 2007)

SloopJonB said:


> Bondo and other auto body fillers ARE polyester. They shouldn't be used on boats as they will permit water absorption - use epoxy fillers only.


SJB,

With respect, that's a pretty categorical condemnation of polyester fillers.

Like everything else, they have their place in the vast order of things. I'd agree that in almost every case, properly thickened epoxy is a superior product -- particularly below the waterline. For cosmetic repairs that are going to be top coated with a good paint, gelcoat or epoxy sealer, polyester fillers are fine (as well as quicker and less expensive).


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## Minnewaska (Feb 21, 2010)

Squidd said:


> Exactly...
> 
> My goal is to fill, fair, put a sealer/barrier coat on and biocide paint...
> 
> ...


Totally agree. Good you got the old paint off, but I would epoxy her up now, paint her and get sailing.


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## SloopJonB (Jun 6, 2011)

PorFin said:


> SJB,With respect, that's a pretty categorical condemnation of polyester fillers.


Indeed it is - on boats. The only problem I've ever had with any filler on any of my boats was with a polyester glaze filler - used for pinholes and such - it failed in several cases.

I've used epoxy exclusively ever since. The cost difference is so minor in the quantities we're talking about that I don't regard any potential savings as worth the increased risk of "do-over" - especially when you figure the cost of quality topcoats.


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## PorFin (Sep 10, 2007)

SloopJonB said:


> Indeed it is - on boats. The only problem I've ever had with any filler on any of my boats was with a polyester glaze filler - used for pinholes and such - it failed in several cases.
> 
> I've used epoxy exclusively ever since. The cost difference is so minor in the quantities we're talking about that I don't regard any potential savings as worth the increased risk of "do-over" - especially when you figure the cost of quality topcoats.


Like I said, epoxy is almost always a superior solution but at times it's overkill.

Sorry about your experience with the glazing putty -- I've been there myself (but only with cars, not boats.) The only thing I've used glazing putty for related to the boat is when making plugs/molds for fiberglass projects.


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## CalebD (Jan 11, 2008)

I know everyone is just trying to be helpful which is what makes this a great place. I know that Squid has done a lot of research on this and actually read these articles on blister repair (posted earlier): Hull Blisters on Boats and Yachts - by David Pascoe, Marine Surveyor
and: Sea Lake Yacht Sales (Kemah, TX) (posted by Brian/Mitiempo)
written by surveyors with quite a bit of experience in hull blisters. 
If you guys and gals read the articles you will find that neither surveyor has a high degree of confidence in conventional blister repair techniques recommended by most boat yards. Can any of you say that you have heard of, seen, or experienced a blister repair job that was effective and lasting, whatever the method?

Squiddo is in Wisconsin and wants to sail his boat this summer during the short sailing season. I can't blame him. Given the likelyhood of eventual failure of the patches (no matter what method or materials) I'd be thinking of using the cheapest, quickest method (polyester) to fair the bottom and go sailing - hoping the patches last a year or two before needing to be readdressed.

I've seen it time and time again on my boat and on other boats in my yard. The owner diligently applies an epoxy patch to the keel or hull and in a few years that same patch needs to be redone. Faulty method you say? Perhaps, or perhaps that is just the way it is. 
I hope I'm wrong as my friends Endeavor 32' got a case of the blisters after being left in the water in the Chesapeake for 5 years. One hundred twenty dime sized blisters in that thin laminate would make Squidd's hull look pretty good.
Anyone know of a sure fire method for fixing blisters? Anyone?
Didn't think so. Conventional wisdom is so... conventional.


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## MarkSF (Feb 21, 2011)

So if the theories are correct, that the blisters are caused by unsaturated mat, is there anything to be said for applying penetrating epoxy (in the hope that it will penetrate and seal the mat better) before the thickened epoxy filler?


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## fiberglass1 (Nov 16, 2009)

Blisters are not caused by unsaturated mat. The mat looks unsaturated after osmotic wicking has destroyed the resin that used to be in the fiber. Caleb - we have a couple boats that were done in the early 80's and still look great. Does that count?
If EVERY step is done correctly, a proper blister job will last decades. EVERY SINGLE STEP!


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## MarkSF (Feb 21, 2011)

fiberglass1 said:


> Blisters are not caused by unsaturated mat. The mat looks unsaturated after osmotic wicking has destroyed the resin that used to be in the fiber. Caleb - we have a couple boats that were done in the early 80's and still look great. Does that count?
> If EVERY step is done correctly, a proper blister job will last decades. EVERY SINGLE STEP!


Well that's helpful. How about telling us what the steps are?

That doesn't explain why some brands have terrible blistering, and some get none. For an example of none, see my Bristol. They have the same bottom paints and gelcoat, and are in the same water. So clearly there's something different about the construction technique. What, is the question.

What we need is more wisdom, not information. Wisdom is backed by information, evidence, and reasoned argument.


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## fiberglass1 (Nov 16, 2009)

There are very good, informative articles and threads, but start with the W.E.S.T. System how-to section on blisters. Instead of going over it inch by inch I'll just tell you the most common mistakes we see.
1. Individual blister grind instead of peel. When you grind out individual blisters there are a million smaller ones you didn't get.
2. Fresh water rinse every other day for the first 2 weeks. Glass fiber is like cotton fiber in your shirt. If your shirt goes over the side are you ever going to get it dry without washing the salt out of it? Of course not. The bottom of your boat is no different, the salt in the fibers will inhibit drying and screw up the epoxy bond.
3. More fresh water rinse to wash away the glycol compounds (one of the results of polyester osmotic decomposition) as they blush to the surface. Once these glycols have dried on the surface they're really hard to remove. Nothing sticks to glycol.
4. polyester or vinylester fillers - why mix chemistry? All epoxy all the way.
5. Nobody seems to want to prime the surface (with neat epoxy) before applying barrier coat. When Interprotect first came out, they wouldn't guarantee the 2000/2001 barrier coat unless you primed with 1000/1001. Now, nobody seems to care about it. We still prime because the neat epoxy soaks in, the barrier coat doesn't.
6. Insufficient millage - most barrier coats require 12 mils cured minimum. That's 4 or 5 coats. Not 2, not 3, FIVE! You know damn well the millage is not going to be uniform, why cheese it?
Hope that helps.


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## mitiempo (Sep 19, 2008)

PorFin said:


> SJB,
> 
> With respect, that's a pretty categorical condemnation of polyester fillers.
> 
> Like everything else, they have their place in the vast order of things. I'd agree that in almost every case, properly thickened epoxy is a superior product -- particularly below the waterline. For cosmetic repairs that are going to be top coated with a good paint, gelcoat or epoxy sealer, polyester fillers are fine (as well as quicker and less expensive).


I don't understand why anyone would want to use a polyester based compound on the bottom. The preparation is the same for polyester or epoxy. True the epoxy costs a bit more.

If polyester wasn't used to start with there wouldn't be any blisters.


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## MarkSF (Feb 21, 2011)

Very interesting, fibreglass1.

Do you have an opinion on why some boats get blisters much worse that others? Whats the difference?


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## fiberglass1 (Nov 16, 2009)

In the 60's all the Miami builders had a guy who mixed the resin for that day. He would adjust the cobalt, promoters, styrene levels for the moment they were about to use the product. It was a very custom, accurate way to do it. Today, we get summer resins and winter resins, that's about it. And there were no chopper guns then, wet out guns yes, but no resin rich gun chopped glass went into those boats. Then, the fuel crisis with rising prices and shortages. When was that, maybe 1973 or 74? Funny thing is....I don't remember any blister problems before the early 70"s. Coincidence? My view is, the resin got "watered down" and ****ty fillers were added to get it back to normal thixotropic properties which resulted in much worse hydrolytic damage. There are plenty of pre 70's boats around with original bottoms.
Also, Bristol was a pretty good organization back then. They didn't allow sub par work. The better the laminating crew, the lower the chance of bad blisters.


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## CalebD (Jan 11, 2008)

fiberglass1 said:


> Blisters are not caused by unsaturated mat. The mat looks unsaturated after osmotic wicking has destroyed the resin that used to be in the fiber. Caleb - we have a couple boats that were done in the early 80's and still look great. Does that count?
> If EVERY step is done correctly, a proper blister job will last decades. EVERY SINGLE STEP!


Fiberglass1,

Yes. That counts and thanks for your input.

If you read the David Pascoe link on blisters he documents at least 1 case of failed blister repair by a 'professional' yard. I guess that the pros don't always follow every step all the time either.

What you say makes sense to me from what I (think I) know about the chemistry of blisters. The hull rinsing and drying out part of what you describe sounds important as do all of the points you made about doing a proper blister repair job.

Fortunately for me, my boat is from 1967, spends winters out of the water and shows no sign of any blister development. Unfortunately for boaters who are further south, like in FL where you are and the Chesapeake, some choose to leave their boats in the water year round which does not give the hulls a chance to dry out. Do you think that this is a contributing factor to developing blisters???

Thanks in advance.


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## Squidd (Sep 26, 2011)

Appreciate all the input I'm getting on this bottom factor...Kinda like "discussing" the best anchor to use...

Here's what I'm seeing...There is no gelcoat on the bottom of this boat... I know what gelcoat looks like, there is gelcoat on the cabin and deck...the topsides are painted, but there is gelcoat below the Britesides ( I saw it when I touched up fender rubs)...

Just below the waterline, (green tape) is a blue line of gelcoat <w/some dark blue paint> and then it goes to the gray "Filler"....

There is no hard gelcoat "solid surface" to sand down to without going all the way down to the fiberglass matt.I don't know where the hard coating went, but it ain't there no mo..










I do not have the time, ambition or money to do a "Full Bottom Job" before I launch this season..I may do it in the future, but I have yet to see a full repair schedual I can believe in.

So I will be forging ahead on a Fill and Fair repair job, resin coating the entire bottom to tie it all together and then a couple coats of hard biocide paint for color and to keep the slime down...

I already have and will use a polester fiberglass filler...The can I have has a picture of a boat on it, says Marine on the label, _waterproof_ and for above and below the waterline use...I'm fairly certain the gray matter on the boat is a poly filler (as do most opinions offered) and see no reason not to continue with it to fill divot holes...

At this point "spot coating" the exposed matt is a non starter if the filler right next to it is permeable, so after filling fairing and smoothing out (with wide spreaders, flat sanders and long boards) I will coat the entire bottom below water line with "Epoxy" resin witch should bond and tie in with whatever chemical soup is underneath... 2 coats and scuff sand for adhesion of 2 additional coats of hard Marine Biocide paint...

That is good enough for me for now and the bottom line is I'm the only one I have to placate anyway...

Will post pics in the Fall...


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## SloopJonB (Jun 6, 2011)

CalebD said:


> Fortunately for me, my boat is from 1967, spends winters out of the water and shows no sign of any blister development. Unfortunately for boaters who are further south, like in FL where you are and the Chesapeake, some choose to leave their boats in the water year round which does not give the hulls a chance to dry out. Do you think that this is a contributing factor to developing blisters??? Thanks in advance.


The conventional wisdom says that boats in the water year round in the south are more prone to blistering but my 1970 Columbia spent 20 years in the water in California, at least 15 in Santa Monica and I doubt it was ever out of the water any longer than it took to slap another coat of bottom paint on the unprepared bottom - not one blister.


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## SloopJonB (Jun 6, 2011)

Squidd said:


> Here's what I'm seeing...There is no gelcoat on the bottom of this boat... I know what gelcoat looks like, there is gelcoat on the cabin and deck...the topsides are painted, but there is gelcoat below the Britesides ( I saw it when I touched up fender rubs)...
> 
> Just below the waterline, (green tape) is a blue line of gelcoat <w/some dark blue paint> and then it goes to the gray "Filler"....
> 
> There is no hard gelcoat "solid surface" to sand down to without going all the way down to the fiberglass matt.I don't know where the hard coating went, but it ain't there no mo..


What is the white layer next to the exposed mat? That sure looks like a glecoat layer.


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## smurphny (Feb 20, 2009)

Thanks for that information FG1. Am going to do a barrier coat job on my old A35 this summer. Is good to hear experienced advice. I'm thinking of just using coats of West instead of Interlux and maybe even incorporating a layer of fine cloth between layers.


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## Squidd (Sep 26, 2011)

SloopJonB said:


> What is the white layer next to the exposed mat? That sure looks like a glecoat layer.


Just at the bottom of the blue line it breaks into the "powdery" filler then the matt

It's like they taped it off an inch or so below the green line and started grinding...

Filler is feathered very thin up on sideds (thousandths) and varys to a 1/16" to an 1/8" in various locations...not a consistant thickness anywhere...


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## fiberglass1 (Nov 16, 2009)

Caleb - absolutely a factor, in fact the MAIN factor. Constant immersion is required for blisters to get going. If the boat is hauled out every year it dries out, when it goes back in the water ingress gets started but doesn't get very far.


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## Minnewaska (Feb 21, 2010)

I asked about the colors above, because I wasn't sure I was seeing the gelcoat either. 

It seems likely that a prior owner stripped the gelcoat off when trying to address the blister problem and then did a bad rebuild. 

Squidd has a good plan. If you're not going to go all in on drying her out, getting the salt out and relaying a bottom (and I wouldn't on a 3k boat), then just get it done quickly and go sailing. See how you make out. 

If it really requires a 5k bottom, I would sooner junk the boat and buy a different 5k boat that already has a good bottom.


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## Squidd (Sep 26, 2011)

fiberglass1 said:


> Caleb - absolutely a factor, in fact the MAIN factor. Constant immersion is required for blisters to get going. If the boat is hauled out every year it dries out, when it goes back in the water ingress gets started but doesn't get very far.


Also good news in my case as the boat will be "dry slipped" mast up on a trailer for a 5 month season then brought home and stored indoors for the winter...

That's about as dry as you can get it/keep it...(and still go sailing)

At that rate my "patch job" may last a good long time...


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## Squidd (Sep 26, 2011)

OK I have applied my first coat of filler to many of the deeper divots, I'm sure I'll do a second for the ones I missed...










Next I laid out my weapons for fairing the surface smooth...I would prefer the random orbital for the dust collection aspect, but the sanding pole with the abrasive screen is supposed to produce a smooth finish with minimal mess when "wet sanded"... My fall back is the 1/3 sheet orbital which is known to produce a smooth finish , but creates a lot of dusty mess...










I'll do test spot comparisons before I get fully into it to see which tool actually works the best for my situation...


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## CalebD (Jan 11, 2008)

Looking pretty good!

Once you start sanding/fairing back you'll probably find some low spots. Hopefully none worth worrying about.


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## Squidd (Sep 26, 2011)

I'm kinda likeing the effect of wet sanding with the pole sander and abrasive screen...

Going from filling to wet sanding is really blending and smoothing the surface without multiple coats of primer and glazing...(I've bondo'ed a lot of old cars up here in rust country)

I don't know if you can see it in the picture but the filler has been blended.faired down to surface level high spots are coming down and sanding scratchs are dissapearing...










All with minimal mess and from a comfortable standing position...Thanks for the tip Gary...


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## travlin-easy (Dec 24, 2010)

Glad I could help, Squid.

Gary


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## johnnyandjebus (Sep 15, 2009)

Trav

Thanks for tip on the sanding screen, I have some heavy bottom work to do next fall and will keep it in mind.

John


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## bljones (Oct 13, 2008)

Squidd, if it';s not too late- ditch the cheap Ace garnet sandpaper and get some good 3M or Norton 3x. It'll save you a ton of time and paper.


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## Squidd (Sep 26, 2011)

Yeah, not too late, but unfortunatly I won't be needing the ace paper... 

The 1/3 sheet sander "bit the dust" a minute after I started it up...I didn't even get to do a test patch..it was an old machine, been sitting on the shelf for many years (I prefer the RO) and must have rusted/corroded up from sitting so long...screeched and locked up...

The ACE "screens" seem to be holding up, I did one side the one side of the boat with 4 sheets (2 packs)... about what has been reported in some of the other "sanding" threads...

The RO is using some german made "klingspore" contractor sheets "Finish Line" brand....I only used 25 sheets to get the red off...and I bet I had 15-20 lbs of "dust" in the shop vac...

I will have more sanding to do, got at least one more round of filler to apply and fair out...


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## deniseO30 (Nov 27, 2006)

Glad your getting there! Sandpaper really varies in quality! The best seems to be available to the auto body business. But, most all auto-body sanding is done with 6" psa instead of the 5" H&L with vac holes in them. Norton bluemag and or green zirconia (3m?) is worth the cost though, I've used it. Home centers seem to sell low quality sandpaper. Also storage makes a difference, long term storage in a damp basement for example,the paper gets soft and weakens the paper's bond with the grit.


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## SloopJonB (Jun 6, 2011)

Squidd said:


> The 1/3 sheet sander "bit the dust" a minute after I started it up...I didn't even get to do a test patch..it was an old machine, been sitting on the shelf for many years (I prefer the RO) and must have rusted/corroded up from sitting so long...screeched and locked up...


Believe me, it did you a favour. That was the first sander I ever bought - it was so horrible I trashed it - I wouldn't even sell it on to some unsuspecting victim. All it did was vibrate your hand - completely useless.



> The RO is using some german made "klingspore" contractor sheets "Finish Line" brand....I only used 25 sheets to get the red off...and I bet I had 15-20 lbs of "dust" in the shop vac...


I've been using Klingspore for years on my DeWalt R.O. - they are very good disks.


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## Squidd (Sep 26, 2011)

It's coming along nicely... two coats of filler dry sand, wet sand and now starting to apply first coat of epoxy barrier coat...

Really smoothing out from the lumpy mess I started with...










And I will admit I have more "gelcoat" layer than I first thought or reported...

The light blue layer was under yet another layer of paint, but is helping me carry a smooth line...there are large "patchs" of filler from previous repair attempts and I guess maybe I was concentrating on them and blinded to how much is still solid...


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## Minnewaska (Feb 21, 2010)

Now that you've exposed a paint layer, it seems like you are back where you started. You want to know whatever you put over it will stick to it. I'm only speculating that the blue was an original barrier coat. No way to tell from here.


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## Squidd (Sep 26, 2011)

Nahh, I'm way ahead of where I started..another coat of epoxy... two biocide to keep the slime down and I'm going sailing...

Remember this is just fill, fair and seal for this year...too many variables laid down to get too excited over for now...









Seems the only way for "permenant" repair is going to be blast or grind "everything" off down to bare fiberglass matt and "rebuild hull" with epoxy and cloth and then start refinishing from there...

Dollar and time wise may be better off with a different boat...If I'm gonna put $7,000-$10.000 in a hull job on a $3,000 boat I' be ahead to sell this for a $1,000 add it to the $7,000 and buy a better looking $8,000 boat...(or a nice downpayment on a $30,000 boat...)


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## Minnewaska (Feb 21, 2010)

Fully agree with not relaying the hull.


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## deniseO30 (Nov 27, 2006)

give it 5 coats and your good to go, most likely won't need to do it again in our lifetime


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## SloopJonB (Jun 6, 2011)

Squidd said:


> (or a nice downpayment on a $30,000 boat...)


Careful, that sounds like the disease is getting a grip.


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## Squidd (Sep 26, 2011)

I know...I haven't even sailed this one yet and I got 4'-6'itus...


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## Squidd (Sep 26, 2011)

OK so I tried a second coat of clear epoxy today...

Clear over clear is still clear... I could not "see" what I was covering/missing so I stopped after a few sq/ft..

Spent the rest of the afternoon "scuff sanding" the dry clear coat hoping the sanding scratchs will guide me as I apply second layer...not totally convinced...

What i would like is to "tint" the next layer so I can "see" where/what I'm covering...

What can I add as a "tint".. I read on google a small amount of artist oil paint woiuld work, mixed with epoxy resin...I have some...any other suggestions...?


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## SloopJonB (Jun 6, 2011)

Squidd said:


> OK so I tried a second coat of clear epoxy today...
> 
> Clear over clear is still clear... I could not "see" what I was covering/missing so I stopped after a few sq/ft..
> 
> ...


Got to a fiberglass supplier and buy some tint - it only costs a few bucks.


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## Squidd (Sep 26, 2011)

WEST SYSTEM - Projects - Adding pigments to epoxy

Dry Anilines and Tempura powder also had high adhesion ratings both of which are available to me .... Better adhesion than the rit dye or the enamel paint suggestions I've read...


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## travlin-easy (Dec 24, 2010)

Don't use anything oil based--it will retard the drying process.

Good Luck,

Gary


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## Squidd (Sep 26, 2011)

I don't know why I didn't think of it eariler...Carbon Black...about as inert and you can get...










Couple drops toned a batch black...just enough to see the new coating...










Two coats epoxy abour 12 to 16 mil barrier on top of fill and fair...starting to look presentable from what I started with...



















Three days of "cureing" while I go off and watch the daughter graduate Nurseing School.. and then back to put two coats of hard Biocide paint on...calling it good for now...( I want to go sailing...)


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## Squidd (Sep 26, 2011)

Finally got first coat on...










One more coat and then a new waterline stripe...


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## travlin-easy (Dec 24, 2010)

Lookin' good Squid!

Gary


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## MedSailor (Mar 30, 2008)

Looking great! And adding the Crestor(tm) to the mix will keep the cholesterol from sticking to the bottom too!

Nice job!

MedSailor


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## bljones (Oct 13, 2008)

Pharmaceuticals, painters supplies, epoxy and a boat- You gotta love this guy's workspace.


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## Bill-Rangatira (Dec 17, 2006)

bljones said:


> Squidd,
> 
> Ditto what jfdub said.
> 
> If you want to be in the water this season, forget you saw what you saw, mix up some slightly thickened epoxy, slather it on the exposed mat, roll it out, mix up some fairing compound, slather it on, sand and shape it, cover it with some barrier coat, bottom paint and go. In the fall, soda blast it and spend the winter cleaning it up.


Agreed only thing I might add is to put some mat and roving layers or at least chopped strand in any big holes

You might want to check into a gelcoat plane? like a electric hand jointer for shaving off gelcoat not sure who makes them but I'm sure someone more knowledgeable might have the intel


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## fiberglass1 (Nov 16, 2009)

No mat. The fiber ends which touch the gel coat (porous membrane) form the "wick" which is the main cause of blisters in the first place.


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## Squidd (Sep 26, 2011)

Got the stripe painted, The Hull buffed an polished and the new lettering on....

Cleaning up nice...Won't be long now till we head for the water...


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## Me Tarzan (May 14, 2012)

Wow I skipped from the beginning to the end of the thread... Great job whatever you did!


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## Minnewaska (Feb 21, 2010)

Outstanding. Enjoy the first sail with her!


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## MedSailor (Mar 30, 2008)

Squidd said:


> Got the stripe painted, The Hull buffed an polished and the new lettering on....
> 
> Cleaning up nice...Won't be long now till we head for the water...


There's nothing lazy about this boat's skipper. I'm just sayin....

MedSailor


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## travlin-easy (Dec 24, 2010)

Really looks great!

Cheers,

Gary


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## Davenire (May 14, 2012)

Yes, it looks outstanding

Excellent Job!


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## Squidd (Sep 26, 2011)

Thanks...Took a little work but saved some boat bucks doing it myself...

Not bad for a $760 e-bay boat...

Got the trailer lights and brakes wired up...Just a few loose ends to tie up inside and out... ready to travel...










I can't believe in a week or so I might actually have to "Sail" this thing...


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