# balsa core repair



## dorourke (Aug 11, 2006)

I just posted a thread for moldy teak, I found that to be the least of my problems today.

I found a soft spot on the starbord bow of my boat that has a balsa core sandwich. I read a while ago about drilling several holes from the inside of the cabin about the size of surgical tubing and rigging a shop vac with the tubing to vacumm or suck the moisture out of the core. What I don't remember is what to use to replace the saturated balsa's fiber to recondition the core. I know once balsa is rotted you can't do anything to repair it, I did hear of a technique that saturated the balsa with a sort of chemical to reconstitute the core itself and not the balsa.

Did anyone here of such a thing? I guess the way it goes is; 

you leave the vacumm going for several minutes in one hole (thirty to fortyfive minutes) then go to the next hole and repeate until all the holes have been vacummed, then you use surgical tubing with one end in one hole and the the loose end in a container of this very thinned epoxy or something of that nature while still vacumming until you see the fluid seeping thru to the tubing.

Sorry for the long winded description, I wish I was paying more attention when I read the article a few years back. I am bent on getting this fixed and all advise will greatly be appreciated. Oh yea!, I did find the source of the problem and am on the path of fixing that too.

Dennis


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## brak (Jan 5, 2007)

Looking at a picture I see you have S2 9.5, if I am not mistaken? I really liked their design back in the day (still do), "well carpeted boat" reputation notwithstanding. But every single one of them I looked at had significant core problems in the deck. What this is attributed to I do not know. 

In any case, I can tell you that I saw quite a few where exactly this type of repair was attempted - drill, dry, seal. It clearly failed every time, leaving an ugly deck that is still all rotten and wet. 

I am not sure what to suggest, but I'd say that the drill-and-dry way isnt going to do much for you. There is now rotten wet paste in between two layers of fiberglass. When I had to repair a small area on my old Beneteau (which did not even register too wet on the moisture meter), I opened it up completely from inside. As I did, water started leaking out. What I found inside was the consistency of tuna from a can - whitish soft chunks, and lots of water. There is no way to repair that, dry that or bring that to any decent condition. In my case I had to fully scrape that stuff off until I got to outside layer of glass (which was pretty thin), replace with new core (I went with marine plywood, thoroughly epoxied, which was ok for that situation but I wouldn't do that for a deck), and then reglassed from inside. It was a hell of a job, though a good learning experience for me  

Anyway, YMMV, I am not a pro.


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## lharmon (Jul 26, 2005)

Brack is right open it up and be certain you have it fixed. He is trying to keep you from wasting your time, money and from making a mess.


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## wchevron (Oct 19, 2007)

i haven't tried it but there is a product called smiths cpes epoxy which is supposed to soak into the rotted epoxy and restore its strength. you can find it at rotdoctor.com


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## dorourke (Aug 11, 2006)

The boat is an S2 8.0B and not well recognised by the S2 community, although I am flattered.

I fear the method of pealing back the interior combing and re coring for the labor intensiveness of the project. Never the less, this boat would be worth the effort to me, I value this thing, the handling as well as the stability makes any passage a compfortable one.

I have heard many of the end of the road comments on this topic, but what can it hurt to try one more thing before gutting the core. Even if this is a failed attempt I can then surelly say it can't be done.

I do have a plan 'B', and that is to gut the aria involved and re-seal it with a stable foam replacement, I'm trying to do this the cheepest way first. If I don't ask then I have no leads.


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## brak (Jan 5, 2007)

ah, I know 8.0 as well, they are essentially a smaller sistership to 9.5 I beleive (a cruising version).

If there would be no harm in drilling - I'd say go for it. However it appears that drilling the deck weakens the laminate, which very well may be detrimental to any future repair.


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## TSOJOURNER (Dec 16, 1999)

Prior to doing anything, you should decide on what your plans are for the boat. Is this something that you have invested a significant amount of money in and want to be able to resell without incurring much loss ? Or is this a boat that you have purchased very cheaply and are willing to walk away from eventually ?

If you want to maintain the value of the boat, don't drill holes in the deck. Don't drill holes in the underside. The reason that I say this, is that 99 times out of 100, that type of fix is not successful for more than a few weeks. You end up with a boat that is weakened and also scarred. Any prospective buyer who retains a surveyor will know that there was a deck issue, that it was repaired on the cheap, and that this type of repair doesn't work that well.

It will take more time and money to repair (or have it repaired) properly, by cutting out the wet core, replacing it and reglassing the area, but the end result will more than justify the expense.

If this was not a big investment for you, and you want to experiment, by all means go ahead and pour potions into the core and see if they do the job. I haven't heard of anyone who has been satisfied with the results, but there are new products coming on the market all the time, and it is conceivable that some manufacturer has come up with something that works.

Good luck and let us know what happens - particularly if this stuff you mentioned does work for you. A lot of people would probably be interested in it.


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## TomandKarens34 (Dec 4, 2007)

Respectfully Sir, half a fix is no fix at all. As a wretched junior member I probably have no right to speak with authority on the subject, but I have re-cored a deck. Personally. I will direct you to my members gallery. Alas I took no "during" pictures, but I did about 20% of the deck. I went through the top, cut out the bad core, and reglassed. It took two years. I believe you'll find that balsa is cheaper than foam and works very well as long as you follow Casey's instructions in his book. His method totally seals the balsa so it can never get moisture in it again, so using expensive foam is not necessary. One of the disappointing aspects of doing a re-coring job is there is always more rot than you think. In my case at least 4 times as much. On the bright side my 33 year old '75 O'Day 25 looks almost new. It's resale value is squat but I really don't care. I regret missing two years of sailing. So it remains a personal decision, but it will be a huge amount of work and time. If you're 34 and used to hard work, it won't be a problem. If you're 58, a smoker, have a passion for good whiskey, and work behind a desk, you're in for a trial.
Now for the "suck out the moisture" method. It requires an industrial grade vaccume pump, the one the HVAC guys use. It works on the principal of lowering the vapor pressure of water till it will boil at room temperature. Under ideal conditions it might work, but it is likely there will be an air leak that will prevent you getting a deep enough vaccume for it to be effective. You'd probably have to have it under a deep vaccume for at least a few days for the moisture to migrate through the balsa to effect a complete drying, if you could get that 29' vaccume in the first place. You'd still have bad core which has broken away from the fiberglass layers and is no-longer structurally sound. In my opinion, you've gained little but the knowledge it won't get worse. You still have the problem of a soft, compromised deck. Pouring epoxy through those holes you've drilled it the deck works for bubbles in the deck that are from delamination only where the core is stable and dry and this fix is not suitable for rotten core.
Best of luck.


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## dorourke (Aug 11, 2006)

Sailorman,

I do appretiate your insight. I payed little for this boat and I do want to keep it and care for it, it would still be worth more than the nominal investment.

Tomand Karens34,

I just talked with someone at the boat yard today and you echoed exactily what he said, "there is no Holy Grail for this but to cut it out and replace it with it's origional balsa core, just seal it as you go and you will likely need to replace more balsa than what it looks like from the stains", he also said "sucking the moisture will take longer than just doing the repair and even then you may not get all the moisture out, just do it if you want it fixed."

I am not afraid of work as it is a labor of love for me. Never been behind a desk and only sip whiskey once in a while, but I do smoke (I accept all your prayers for me to quit). 

Never the less. I put this question out to all of you to get the streight up on my delima, honesty is always better than a misleading compliment. Thanks to all of you I am focusing on the correct way to do this.

Dennis


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## brak (Jan 5, 2007)

That said, if I were faced with an issue like that right now, I would start by sailing a season, and begin repairs in fall. It will get worse in this time but not by much and I think doing repairs like these while everyone else sails - is just not fun   Winter is there for that stuff.


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## camaraderie (May 22, 2002)

I agree with Brak but add the proviso that the water is coming from somewhere and you need to find the leak and kill it.


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## Maine Sail (Jan 6, 2003)

*Some insight..*

Having done a few re-cores in my day and having removed the god awful messes left over by "injection" I can say this: DO NOT INJECT YOUR DECKS!! At best it will make you feel better but it will DO NOTHING. Unless you have some small pockets of DRY delam don't bother injecting. I've actually seen what it looks like after the fact, It's not pretty and it's not repaired! Buy some balsa let it rot then inject it with epoxy and let me know how far it gets or "penetrates". Having ripped this type of repair apart I can tell you it WILL NOT penetrate the way these "penetrating epoxy" companies say it does. Water takes years to migrate rot & penetrate balsa and epoxy cures in about 8-24 hours.. Think about it??

Removing this mess after the fact is labor intensive compared to cutting away skins & balsa and requires lots and lots more grinding (epoxy is very tough stuff)!

Do yourself a favor and wait until you are prepared to do it right..

Repairing from the top is the best method unless of course you're well versed in the art of vacuum bagging. Think gravity and know that it works against you upside down..

For more on the subject read this:

Glissando's Deck RE-Core


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## brak (Jan 5, 2007)

The part about vacuum bagging I could never understand. I know it results in less resin use, and probably in tighter and neater laminate, but it is underneath and, probably, hidden by upholstery and the like (in case of S2 - carpeting is glued onto it, so it's all nice and fuzzy).

I reglassed a few things upside down (including that core repair I've mentioned, though it was not hugely extensive. Depending on how the deck is built, the upper layer of laminate above the core might be thicker (or thinner) than the lower. In my case, the outer laminate had a few more layers (like 2) where the inner had essentially one. 

The only true inconvenience of working upside down is the need to cover everything underneath - but lots of drop cloth or paper would achieve that. Well, and use old or disposable clothes  Other than that, decently mixed epoxy seems to stay on (I used medium viscosity resin and medium hardener, though now I would have gone with a fast hardener, probably). The cloth seems to stay in place even without tacks or other fasteners (though I used masking tape occasionally).

As time consuming and dirty as this job is, it is not all that hard. The upside is - your decks continue looking nice and undamaged. And not having to repaint the deck (and restore the antiskid and the like) is probably saving more time and effort than had gone into upside down work.

Disclaimer: I've done exactly 5 things upside down - the core repair, a few fixes for previous fixtures on deck and some work for windlass installation. I can't say it was fun (but then again none of glass work is) - but I am essentially a complete newbie and still could do it. 

So, FWIW my vote is for the inside repair.


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## NOLAsailing (Sep 10, 2006)

I read this thread when I had a brief moment over the weekend and really wanted to type out a long response. Coincidentally, I'm concluding precisely this project on my boat (and I've done it on others).

Fortunately for me Halekai and Brak have said just about everything I wanted to.

On my first boat - a Pearson Triton like Glissando - I did it both ways. First, I tried the drill and fill method and, when that failed, I did a proper recore. So, I understand the reluctance to cut open the deck and start grinding away. Likewise, I understand why we encounter this question so often here. As daunting as recoring seems to those who haven't done it, it's an indication of sanity that you'll ask if there's an easier way.

The rub is that properly recoring _is_ the easier way. By the time you drill all of those little holes and painstakingly inject resin, you could have the skin off, the core removed, and the area prepped for new core and laminate. If you drill and fill you'll end up with a ruined upper skin and a lot of small epoxy plugs. The deck will still be very weak.

If the deck is flexing, it means the balsa is soaked and completely deteriorated; it must come out.

I prefer to do it from the underside. On this most recent project, I repaired a large area in my foredeck and a smaller one on my sidedeck. I've spent three full days on the project and I've removed the old core, replaced it with new balsa, relaminated the bottom skin, and re-fiberglassed the seam. I have two more evenings of work to rebed the hardware and I'll be ready for sailing. I'll paint later (both sections, conveniently, are in lockers). This does not have to be a tremendously time consuming process.


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## mikehoyt (Nov 27, 2000)

I also tried both ways.

My dock mate had a soft area on coachroof. He drrilled holes, let it dry as best it could and injected West Epoxy. Then he rolled on gelcoat in a stiple pattern to match the non skid area. His repair workd fairly well but after 5 years a few of teh expoxy plugs are visible.

That same year in the fall I attempthed to repair my cockpit floor in this fashion. I drilled A LOT of holes and tried to dry out. Then injected epoxy (Industrial Formulations Cold Cure). As I was refinishing entire deck anyway this was the time to do it. Floor felt less bouncy and looked very good with the new finish. It held up for about three years but was not the best cure. There was still some water in the core which would seep out around three of these epoxy "plugs" on really hot days when the deck was warmed by the sun.

Two years ago I cut out the top latyer of glass and chiselled out the core from the cockpit floor. Taht took about 1 day. The epoxy did indeed make a mess and was a bit difficult to remove. Of course since the area was never sufficiently dried it did not adhere all that well which made removal easier. I then spent the next day cutting out new core sections (wood) and put in several layers of cloth and matt and then resin followed by core material. Day three I built up the surface over the new core with more layers of matt/cloth/resin. Day four was resin with West 407 sandable filler. Day five it was sanded and then ready for primer and paint. 

Actually for the floor I used Polyester forfaster cure times so the entire project from cutting out old core to applying primer was ONE WEEKEND. Around th chainlplates I used epoxy following same method and it took A LOT longer.

The repair around chainplate areas has held exremely well and looks no different than rest of deck. Repair/recore of cockpit floor is more recent but is solid and looks great with no problems.

The water you dont get out will freeze and expand and cause problems. With teh recore method you get rid of all that. And yes - teh removed core was disgusting and thoroughly saturated and far more extensive tahn at first thought.

Recoring of decks is very simple procedure and one I would not hesitate to do again.

Mike

Formerly Full tilt 2 and now Nut Case


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## zz4gta (Aug 15, 2007)

brak said:


> That said, if I were faced with an issue like that right now, I would start by sailing a season, and begin repairs in fall. It will get worse in this time but not by much and I think doing repairs like these while everyone else sails - is just not fun   Winter is there for that stuff.


Exactly what I plan on doing, weather is too nice to have a boat and not use it right now. My decks don't have noticable soft spots, but the laminate on the inside is cracking and leaking water inside the boat. The water that is coming in is red/brown and disgusting. Can't wait until this fall when I get to fix all that. Also want to re-bed all the deck hardware and chain plates.


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## dorourke (Aug 11, 2006)

Wow!!

Lots of good advise and I'm glad to hear of so many others who have done core repair, I'm encouraged. I am going to sail this summer and while sailing I am reading Casies book on repairing it, I am taking notes on those of you who have tackled this job yourselves. I might pull her out early for the job. I also have found the leak and temporarily sealed it from the deck side.

As far as any scars go I am leaning strongly on going with my origional thought of getting it from the inside as the carpet will cover the evidence.

Dennis


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## TSOJOURNER (Dec 16, 1999)

see don casey's book, "sailboat hull & deck repair". i tried to save my deck by a few other methods only to finally give in & do it by the book. 
p.s. there are several interesting looking deck coatings out there now like durabak or grizzly grip which would work well as no skid covering instead
of sand paint etc.
jim, s/v mello moon


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## merttan (Oct 14, 2007)

I have the same problem on my 22 footer reinell... I'll share what I plan to do after a looong research on it... Repair it from inside if possible... Cut deep enought not to damage the top skin, then remove the balsa core and inner fg with a razor... Knowing the extension of the rotten area is upmost important issue. I was told to start cutting about 1-1.5" far into the undamaged core to create a reliable bond ... Since balsa is sold in precut 1"x1" pieces held together with a mesh, cutting rectangular or square pieces should ease the project a bit... 
Unfortunately, I haven't heard any reliable results on chemical agents that rebonds the rotten balsa, yet.
As some mentioned, don casey has the fairly easy to follow instructions on his book. 
Good luck, i feel your pain...
PS: It's fairly easier to figure the damaged area after a heavy rain or washing the deck with lots of water... Once you drill small holes, it'll start dripping... Keep drilling until no water drops... That's one of the ideas given to me by a fg repair guy...


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## sailingdog (Mar 19, 2006)

Brak-

The comment halekai made about vacuum-bagging is because if the repair is vacuum-bagged, the fact that you're working on the underside doesn't really matter, since the vacuum bagging will hold the repair in place until the epoxy cures.

Merttan/dourouke-

Cut in from the top... it'll be a lot easier to properly repair the deck if you're not trying to work against gravity. I would bevel the cut into the un-damaged balsa, so you can scarf the new balsa in with the old balsa and make the repair as seamless as possible.

If you try doing this from the bottom, getting a good bond between the balsa and the upper laminate layer will be difficult, since gravity will then to cause the balsa to pull away from the upper laminate, and that will leave you with voids, weakening the repair considerably. *For a cored deck to function as designed, the two laminate skins must be tightly and completely tied to the core, so the core acts as a stress web, and the laminate acts as an "i-beam". *

Don't drill holes... even if you're going to do a re-coring job. It will make doing the repair more difficult than it would be otherwise.


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## mikehoyt (Nov 27, 2000)

I just completed recoring sections around several stanchions. I have photodocumented the process at this address J27 #150

Four areas required approximately 30 hours of work. This includes cutting, cleaning, layering, recoring, fairing, sanding and refinishing

Mike


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## Gary M (May 9, 2006)

I have an S2 9.1, which all have deck coring issues. I cut out one section around my starboard chain plate when I was replacing that bulkhead and had a professional come down and do the final work on both. 

I cut out a section of the side deck from the bottom about 1 foot square. What the pro did, and it looked pretty easy, was to set the new coring in place and hold it there with a slightly larger piece of 1/4 " plywood which was held up with a 1 by 1/2" board kinda wedged in. He put waxed paper over the plywood so it would not attach to the underside. Same support for the two layers of glass that came next.

I have 4 more spots to do in the main cabin area and I plan on doing them all this fall from the bottom, using the same method. I wil be removing the carpet that S2 is famous for in the entire main cabin and covering with a nice marine foam. 

Good Luck
Gary


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## Maine Sail (Jan 6, 2003)

*Having done ..*

Having done a fair number of core repairs and re-done previous owners "drill & fills" I can assure you of a few things:

#1 Working from the TOP is the ONLY way to avoid voids!! It's called gravity!

#2 The water took years and years to penetrate and rot the deck you will NOT dry it sufficiently in even a month or more. you need NEW balsa!

#3 These "Ginsu" equivalent "penetrating epoxies" are BS!! Period and end of story! As I stated before it took the water years to penetrate that much core. Epoxy begins to kick in as little as an hour or two at which point it begins to thicken and or NOT penetrate!! Having cut open my fair share of "drill and fill" short cuts I can assure you the epoxy penetrates balsa all of about 1/16 of an inch if that!!

Try this experiment. Take a piece of balsa and drill a 1/8" hole. Now inject that hole with "penetrating epoxy" and let it kick. Now chip away the balsa around the hole until you find it solid and hard where the epoxy "penetrated" it. I've done this and I think you'll be amazed at the snake oil BS you've been sold!! Again, years for the water to penetrate but an hour or two for the epoxy?? Can you say "Ron Popeil salad shooter" ten times fast..

Unfortunately, there is NO easy way to do this job and going at it from underneath will get you a sub par repair unless you have serious vacuum bagging experience and remove the entire inner skin then completely rebuilt the lamination schedule for the inner skin..

Unless your deck is soggy at a key structural location like a mast step, chain plates or stanchions sail it until winter then tackle this job from the top..


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## CrazyRu (May 10, 2007)

halekai36 said:


> Having done a fair number of core repairs and re-done previous owners "drill & fills" I can assure you of a few things:
> 
> #1 Working from the TOP is the ONLY way to avoid voids!! It's called gravity!
> 
> ...


Having done a fair number of wooden boats repairs I would say that penetrating epoxy ARE NOT BS. They will not set three to 7 days, they have very good penetrating properties, they are great product.

And they are not designed to fix large structural panels, as balsa core.

First of all - roted wood mast be dry before applying penetrating epoxy. It is not possible to dry out wet roted core, period.


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## Maine Sail (Jan 6, 2003)

CrazyRu said:


> Having done a fair number of wooden boats repairs I would say that penetrating epoxy ARE NOT BS. They will not set three to 7 days, they have very good penetrating properties, they are great product.
> 
> And they are not designed to fix large structural panels, as balsa core.
> 
> First of all - roted wood mast be dry before applying penetrating epoxy. It is not possible to dry out wet roted core, period.


With all due respect I think you are confusing "working time/pot life" with "full cure time".

Smith & Co's CPES is the most widely known of the penetrating epoxies. At 68 degrees it has a max pot life of 8 hours! That means it essentially STOPS penetrating at about 8 hours many have shorter pot life time. With epoxies the longer the pot life the longer the full cure. Full cure and workable pot life are totally different.

For a truly dry rotted piece of non-encapsulated wood, like you referenced, CPES works ok. Encapsulated balsa is NOT dry rotted it's wet rotted and CPES or similar products don't work well for THIS application. I've torn it apart many times and seen it's failings and lack of penetration..


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## TSOJOURNER (Dec 16, 1999)

*Couple o' blogs with pics*

ttp://mangomadnessj30.blogspot.com

ttp://sailrattleandhum.blogspot.com/search?updated-min=2007-01-01T00%3A00%3A00-08%3A00&updated-max=2008-01-01T00%3A00%3A00-08%3A00&max-results=27

add the "h" to the front of the links


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## mikehoyt (Nov 27, 2000)

Mango

Nice job. Looks similar to my process on Nut Case (J27)

Intersting similarities. My first section I cut out too large an area because I thought the wet would have spread further. (of course the next sections I had to cut out more than I originally intended because it has spread). 

The deck appears flat but is actually sloped and to different degrees as you move fore or aft. The pain would be with what I called the levelling coats. thickend epoxy (I used West 407) which would sag downhill. This meant the next layers there were always small areas to build up from this. I found after glassing in the new core material that two layers of thickened epoxy that I called levelling layers were required followed by two skim coats to fill in holes from bubbles, etc.... Always one more skim coat than expected and usually when running out of time.

As for rain. I have found that so long as the epoxy has kicked and the area is sealed to keep water out of the core it usually is OK if the rain is light and several hours later. I found the biggest pain with rain would be during refinishing process. It seems to always cloud over and start to spit just as i am about to roll on new paint.

I love the interior pic of the J30. When compared to J27 it is a castle.

Mike
J27 #150
Nut Case


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## TSOJOURNER (Dec 16, 1999)

Three years ago I had to replace a 3'x3' section of my cabin top due to rotten core. I cut through the top and dug out as much rot as I could find. I cut 1/4" x 2" strips of marine grade ply and lay them fore and aft and the second layer port to starboard. I pored epoxy over each layer filling in all of the gaps. After the epoxy hardened, I epoxied fiberglass matte over the plywood to match the rest of the deck. I haven't had a leak or any visible problems since. This project took about 2 weeks. If you want to see the pictures I took during the project, let me know.


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## sailingdog (Mar 19, 2006)

RVRDGN-

Not a big fan of marine plywood as a core material. it's a lot heavier than balsa or foam and has the worst characteristics of both. IMHO, you would have been better off laying in balsa or foam, rather than putting in two layers of plywood.


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## fredmole (Nov 28, 2002)

I am going to be soon joining the recore group and it is always interesting to see how others deal with this problem. For my 2 cents worth, unless you are very good with resin and fibreglass, I would recommend going in from the top. Gravity works with you not against you, you have a fraction of the fumes (even if you do have a double cartridge organic vapor mask). Even from the top i would recommend vacuum bagging as it inevitably makes for a better cure and helps eliminate any trapped air or voids. Drilling, nope, not going to work, it needs to be DRY in there. I would take a zip disc and cut around the rotten area to expose the rot and remove the surface laminate. *my question is ---- if one can get the surface laminate off in one or more pieces (obviously there would be a size limit), and if it is not compromised, can you resin it back on to the new core and then only be left with a seam to fill?? *And under the mast step would I be best to use just laminations and no core? Will that give it more strength in that area or will it compromise the flex (I think that it would work) Also I would think that an iso formula of resin might be stronger and/or better than the general purpose or layup resins. The general purpose of course would also have to be sanded before each layer of glass to remove the curing wax.
Glenn/fredmole


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## jnj (Sep 22, 2002)

*Repairing the core*

Just a few years ago there was a sailing magazine article concerning a deck core problem. The boat owner addressed the repair from underneath the deck in the forward berth: carefully scoring the edge of the entire skin under the deck, removing same in one piece, scraping out the offending sludge and replacing it with some sort of honey-combed synthetic core with glue or fiber-glass. The skin which was removed was then glued-up and replaced. It was then temporarily pressed in place with a labrynth of wood and plywood supports to secure the sheet to the core and upper deck. Only the cut edges where the removed sheet met the fixed part of the forward berth ceiling needed refinishing. The result was complete satifaction: providing a large solid deck with no evidence of drilled-hole repairs on top.. The drilling and filling method is OK for attaching hardware and such where you need a solid bolt through surface but unless you can see the damage underneath you'll never know where the trouble ends.


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## sailingdog (Mar 19, 2006)

Yes, but you'd need to grind and glass over the edges anyways.

Having solid fiberglass, instead of cored laminate, beneath the mast step is probably a very good idea. Also a good idea to have solid fiberglass at any high load hardware mounting points-winches, cleats, line jammers, windlasses, etc. 


fredmole said:


> I am going to be soon joining the recore group and it is always interesting to see how others deal with this problem. For my 2 cents worth, unless you are very good with resin and fibreglass, I would recommend going in from the top. Gravity works with you not against you, you have a fraction of the fumes (even if you do have a double cartridge organic vapor mask). Even from the top i would recommend vacuum bagging as it inevitably makes for a better cure and helps eliminate any trapped air or voids. Drilling, nope, not going to work, it needs to be DRY in there. I would take a zip disc and cut around the rotten area to expose the rot and remove the surface laminate. *my question is ---- if one can get the surface laminate off in one or more pieces (obviously there would be a size limit), and if it is not compromised, can you resin it back on to the new core and then only be left with a seam to fill?? *And under the mast step would I be best to use just laminations and no core? Will that give it more strength in that area or will it compromise the flex (I think that it would work) Also I would think that an iso formula of resin might be stronger and/or better than the general purpose or layup resins. The general purpose of course would also have to be sanded before each layer of glass to remove the curing wax.
> Glenn/fredmole


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## TSOJOURNER (Dec 16, 1999)

*Spongy Deck*

 Oh God, I am so confused on this subject, I don't know what to do! Have read Don Casey's book, and would rather go from the top side to cut out the bad spot on the foredeck. However, we have some sort of old rubber coated non-skid, that can't be removed or painted, so I just ripped out the headliner underneath, planning on seeing what's what under there.
I was thinking of cutting it out and using thin layers of marine plywood to coating each with epoxy, but now I really don't know what is best. The guys in the marina are all telling me to just inject epoxy, but how do I do that from the bottom up anyway. We have a 1978 Mariner 28 and I have been putting this repair off for quite a while, but it is getting a bit crackly under there, so I thought it was time. Help!

I am in the process of reading all of the old posts on this subject, so maybe I'll get some more ideas from there as well. Thanks.


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## US27inKS (Feb 6, 2005)

I did mine from the bottom up, as the interior needed to come out anyway. To say it's a big chore is an understatement. Since I had no idea what I was doing, I didn't save the original interior skin. You can't imagine how much fun it is trying to lay up a 50x60 inch piece of resin soaked biaxial cloth. Going from the inside isn't a bad deal if you already have to pull the interior out, or have a very good compelling reason not to cut the outer skin off. Either way, save the skin. Much easier to reattach the skin than make a new one.

As far as coring material goes, it really depends on what the loads are in that area of the boat. My boat came from the factory with balsa, foam and plywood. Since I'm not an engineer or a naval archtect, I stuck with what the factory put in there. Of the 2 materials I had to work with (the foam was good) the balsa was much easier to work with.

FWIW, I saw a chart somewhere a couple years ago comparing the strength of different coring materials. Plywood wasn't on the list, but most of the structural foams and honeycombs were there as well as balsa. Balsa was the strongest by far. Go figure.


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## NOLAsailing (Sep 10, 2006)

*Here's a post I made on another forum - you may find it helpful:*
_____________________________________________________

I know this topic has been covered a bit, but I spent last weekend in my anchor locker and I'll be spending much of this weekend in the same place. So, I thought I'd hit this horse one more time and reiterate the importance of properly sealing hardware.

I knew about these spots when I bought the boat last year, but I've waited until now to repair them. A good section of the foredeck forward of the bulkhead needed to be replaced, as did a smaller section near the anchor locker. The foredeck was inundated with water from a deck plate and the waste pumpout fitting. The area around the anchor locker was damaged by the hinge screws.

Here's the cross section of deck with the deck plate removed:










I did this from below so as not to ruin the deck finish. Here's the first cut:









Here's the exposed core with the lower skin removed. Note the two pieces of wood right in the middle of the deck. This came from the factory as there was no indication of a previous repair in this area. An old foredeck cleat had two fasteners through the wood (see the epoxy plugs), but the other two were through regular balsa. It's strange and I'd love to why these two pieces are here. Did TPI run out of balsa?









I don't have any photos showing the new core exposed as I laid up the new core and replaced the lower skin in the same operation. I wasn't about to touch my camera. So, the two photos below show the lower skins replaced. In the anchor locker photo, I put that brace back for the picture. There were three braces in place while the epoxy cured.



















Since these photos, I've water washed the repair to remove amine blush, sanded the area, and solvent washed it.

This weekend, I'm going to grind the seam back several inches on each side and reinforce with two layers of tape. Eventually, I'll repaint both lockers with Bilgekote, but that will be done later.

This work could have easily been avoided if the core was isolated from these fittings with thickened epoxy. Before the new hardware is installed, all fasteners or through-deck hardware will pass through the epoxy, not the new balsa. I omitted a lot of the core in the area where the deck plate passes through and I'll ream out the area around the waste pump out fitting. Fasteners will be installed in the standard way - potting the overdrilled holes with thickened epoxy and drilling and tapping the holes for the fastener.

The first time I did a recore from the inside I made a few mistakes. The largest mistake was not sufficiently preparing the braces for shoring up the new core. This time around, all of the braces were cut and set near by, so that went much, much easier.

Another difference is that I was able to reuse the bottom skin. On the Triton, the skin was not salvageable so I just laminated a new lower skin. I had some issues with trying to install pieces (particularly the biax) that were too large and therefore were a real challenge to keep from falling back off the overhead surface. It went a lot easier when I started using smaller bits of glass.

This time, the old skin was replaced. However, I'm not convinced that's really the best way. You still have to clean and prep the old skin, it has to go back in precisely the same location (meaning your going to hold in place until the epoxy kicks and you can add the braces), and you'll still have to grind and glass the cut seam. It seems that with that much effort, it may be easier just to lay up new glass.

The only minor downside this time was gluing myself to the drop cloth. Last time I stuck the back of my head into fresh glass, so things are improving with practice. No haircuts needed (yet).


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## NOLAsailing (Sep 10, 2006)

The project above is finished (except for paint, which I'm putting off as these repairs are in lockers). Here's a photo of the isolated deck core. It doesn't do any good to recore, unless you solve the source of the water ingress. If balsa stays dry, it will stay good indefinitely. I've seen 45 year old core that is bright and dry.


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## TSOJOURNER (Dec 16, 1999)

I have worked on my Able 20 for 4+ years. The previous owner glassedn 1/2" marine plywood under the foredeck and other areas with 1/4" plywood. I also cot it out from the top and laid glass and marine plywood in the deck. At other places I drilled 1/4" holes in the top and it looked like a pegboard. I dried it with time, fans and acetone and injected epoxy w/ a large syringe. I spent eons fairing it w/ fair 
results. 
This is the most tedious project I've ever undertaken


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## sailingdog (Mar 19, 2006)

NOLASailing-

It was a fairly common practice to replace the balsa core with marine plywood in areas of high load, like where cleats would be mounted. Not a great practice, but fairly common. That's probably why there was those two pieces of plywood there. However, they look like they were put in the wrong place...


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## [email protected] (Jul 26, 2000)

Hi Dennis,

I have used Smiths CPES Epoxy system, which I purchased from Jamestown Distributors in RI.

". . . there is a product called smiths cpes epoxy which is supposed to soak into the rotted epoxy and restore its strength. you can find it at rotdoctor.com"

There's a number of articles around on how to do it, but in my search, the ONLY epoxy (I did call West Systems Applications) which claims to work in damp (not wet) environments.

In my case, I had mushy balsa core near my mast step, but I think under the mast step I had plywood core. No matter. First off, I began the project in the fall in central Massachusetts after I had it fully covered.

I used a moisture meter to determine the worst spots. In a 1 foot pattern around the mast step I drilled 1/4 inch holes (using a drill stop) 1/2 inch deep. Sucked out as much moisture as I could with a baster.

I tried the suction with a vacuum cleaner with very limited success. I think next time I'll investigate the "vaccum bagging" technique for this purpose.

I left an oil filled type heater on inside the boat under the mast step area, and left for a 2 months vacation. We came back 5 months later, giving the whole thing 5 months of non-freezing drying out.

I used the Smiths CPES (two parts, I recall). One part is very thin, gets soaked up by the rotted and consolidates the wood into something hard that will mechanically hold the fibers and epoxy. I did that. After curing was done, I sealed the whole area with epoxy, smoothed it down and repainted the area with skid proof paint.

CPES is sold by "Temperature Range" of use, so be sure to get the one thermally designed for your temperature zone.

The traditional method, and perhaps the best method, is to strip the fiberglass back, cut out the offending core, and replace the same with either more end cut balsa or man made 'honeycomb' material.

(Also see West System materials for "How To .." ) Also see "GitRot" for similar material. But neither claimed any fame to working on 'damp' wood. Only dry material.

The CPES system is similar to what "Old House" restorers use to repair well rotted timbers and deco pieces. I had used the home restoration stuff by Minwax to repair one of my older single hung window sash, so I had some knowledge of what kind of repair might work.

If you ask me, now is two years later, how well is the repair holding up, I would be at a loss to say how well, unless I ran outside and drilled a couple of holes to investigate (which I am not). <smile>

My coach roof system appears to have plywood core under all major fittings (grab rails, mast step, hatch slides) and balsa core under the rest.

I also have a double, or what appears to be a double core system. Perhaps what I have is the "coach roof" of two fiberglass molds with the core in between them. Then a void between the inner salon coach ceiling and the coach roof. Hmmph that makes sense.

btw I have a 1978 Hunter 27

Bob

Here's a couple of web pages I found along the way: Unforunately, this system won;t let me post them until after I submit 10 posts! Desolee'

Just search on the following terms. ( For every rule there is an equal and opposite workaround. Hah!) OK, these searches both work
</smile>*"Smiths Warm CPES Epoxy"*

<smile>"Restoration of Rotted Wood with Penetrating Resin"

</smile>


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## TSOJOURNER (Dec 16, 1999)

Here's my experience with the balsa core repair from the top. In case anyone wants to read or see pics of the process.
Replace "XX" with "tt" (can't hyperlink, friggin forum nazi's.)


hxxp://mangomadnessj30.blogspot.com/2008_04_01_archive.html


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## jbondy (Mar 28, 2001)

This is an important thread, with lots of good info for folks faced with this kind of repair. Having done this both from the top and from underneath, I add my vote to the "it's better on top" crowd. Maybe if the area is open enough to allow good bracing, or you're already into the equipment needed to do vacuum bagging it makes sense to do from underneath, but for most of us, that's not the case. hen working from above, you're not fighting gravity and everything you need to access can be gotten to easily.

I totally botched an underside repair, which I atempted to try to preserve the non-skid. Because it was where the chainplates pass through the deck, I decided to make it solid glass so that there would be no core to rot in the event of future water incursion. I used thickened epoxy expecting it to hold each layer glass in place until it set. The glass sagged, and while I was trying to smooth and it up from below, the epoxy hardened, leaving voids. So I ended up filling the voids from above with epoxy, drilling holes into the non-skid I was determined to preserve. The uneven nature of the glass I had laid in from underneath allowed the thin epoxy used to fill to run down into the cabin. I had to take an epoxied piece of plywood that I covered with very thickened epoxy to put a layer underneath to seal it all up so I could fill from above. The space was so constrained that I could not block the plywood in place from below, so I had to drill through the deck and use screws from above to hold the plywood in place until the epoxy cured. Now I had more holes to fill. I should have ground out my sgged glass and started over, but by this time I was too far along. It eventually worked out, but I'd have been done days earlier if I had just gone in from above.

The above story was for a 10" by 16" section of deck. I recored the entire fore and aft decks of my Typhoon from above in less time than this small repair took from below. But individual results may vary.


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## OrangeOwl (Jun 13, 2007)

Gary M said:


> I have an S2 9.1, which all have deck coring issues.


I happen to be looking at an S2 9.1 and the survey turned up some soggy spots in the deck. Does anyone have a recent idea on cost for these repairs (especially if done by the yard - between work and small kids the spare time for a few recore jobs isn't really there). Looking for an idea on how much to negotiate off the price.


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## sailingdog (Mar 19, 2006)

OrangeOwl-

You're a bit OT and probably would be much better off starting a new thread asking about repair prices... it ain't gonna be cheap. It would also help if you said more about where the soggy spots were, since if they involve removing and rebedding hardware, the costs are going to go up. It would also help if you said where you were located, since someone may know of a vendor that can do the work or who to avoid.

I'd highly recommend you read the *POST* in my signature to help you get the most out of your time here. It has tips on searching sailnet, writing a good post, etc..


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## camaraderie (May 22, 2002)

Orange....walk away. You can't possibly know the cost if there are multiple spots and to fix professionally will be a large portion of the total boat value in this case.


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## US27inKS (Feb 6, 2005)

OrangeOwl said:


> Looking for an idea on how much to negotiate off the price.


Almost all of it.


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## timangiel (Sep 8, 2006)

If you recore from the top, and the area to be repaired is an area with non-skid, can the non-skid be restored or are you forced to make it smooth and cover with a non-skid paint?


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## NOLAsailing (Sep 10, 2006)

It is possible to restore the molded in non-skid pattern. Not easy and perhaps not perfect (a disclosure: I've looked into it but never done it). There's a company called GibCo Flex Mold. They make the non-skid patterns placed into the molds when boats are laid up. They also sell sheets of their pattern material and directions for how to do the repair.

Essentially, you complete the recore and fair the area. Then you securely tape of the area you'll be reapplying the pattern to (excess gelcoat will squeeze out). You pour color matched gelcoat onto the area and press the mold pattern securely into place after spraying it with a non-stick agent. You let the gelcoat cure, remove the pattern, and voila.

One very cool thing is that the company will send you a pattern kit for the asking. You bring it out to your boat, match the pattern to your non-skid, and place the order.

_edit: here's a link to their basic webpage: Gibco Flex-Mold - your pattern source_


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