balsa core repair

[camaraderie]

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.

[Maine Sail]

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

[brak]

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.

[NOLAsailing]

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.

[mikehoyt]

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

[zz4gta]

Originally Posted by brak

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.

[dorourke]

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

[westerly84]

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

[merttan]

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...

[sailingdog]

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.