Bulkhead Replacement and Resin Coat - Buccaneer 295

[jboswell]

Hey all, I am almost finished with the teardown (to the hull) of my Buccaneer, and I am planning to start the rebuild here in the next couple days, hoping to finish a majority of the interior before the summer ends, or at least get it up to a sail/liveaboard ready state.

First thing is first, everything inside was rotten, water damaged, or had termite damage, all that stuff has been pulled out. I have ground everything down to the hull except for the last two mast support bulkheads, I plan on redoing those after I get the other 4 bulkheads cut, sealed and put back in.

I want to seal all the wood going back into the boat to prevent much of the same damage that caused all this work to be necessary in the first place. I want to seal the bulkheads (structural) and all the benches/vberth/cabinets that I put back into the boat.

From what I have read so far I am still not sure that this is a good idea, I was concerned about moisture density in the plywood and possible cracking or other issues from the heat and cold affecting the water in the wood.

The end goal is to put a few coats of poly resin (the first being thinned with denatured alcohol) and then a gelcoat, sand it down really fine and get a nice glossy professional looking surface out of it.

I don't necessarily think I need to completely seal them, a few coats of resin should still allow them to breathe a bit while not allowing enough water to get in and form mold/rot, and also keep the buggers out, effectively solving all my concerns.

Am I headed down a bad path? The wood is 3/4" hardwood ply, by itself it is plenty strong, I am not planning on adding glass to increase the strength of the bulkheads, just giving them a few coats, bringing a shine out and then tabbing them in...

Thanks for any help you can give me!

Joe

[Landlubber]

Joe,

I would suggest that you do not use poly resin on the wooden bulkheads. Epoxy resin is a far superior product and will protect the wood veneers better. There are epoxy solutions, such as Everdure (International) that have anti fungicides in them, they really do work and will toughen up the surface, but not suitable for gelcoat coverage (it should be flow coat (waxed gelcoat) anyhow mate, the gelcoat will not go off exposed like that).

I would suggest that over the base coat that you use a high build primer (epoxy again) and primer surfacer...nice easy products to sand smooth. The final top coat would be two pack urethane (linear) sprayed, or rolled and tipped.

[jboswell]

Here is my concern with using epoxy... The people who I bought the last batch of epoxy I am also testing with told me that you can't lay poly resin over epoxy. Now, I am not sure I will be attaching anything to the bulkheads, but if I am, doesn't this kinda force me to use epoxy everywhere on the boat from here on out? Or was the vendor I talked to uninformed?

I am planning on sealing all the wood I put in the boat, every piece, VBerth/cabinets/engine compartment/etc and literally every other piece of wood going onto the boat, which would mean I would have to use epoxy for the lot of it, since the plan isn't to glass this stuff anymore the cost really isn't too much of a concern I suppose though... Hmmm.

The anti-fungicide is a pretty nice addition though, seems like a really nice longevity factor.

Right now I am just using the regular poly resin with a waxed topcoat with some white additive in it, was planning on just putting it on thick and sanding smooth and polishing. As per the surfacing stuff you mention, oh boy I think I have some reading to do tonight lol.

Thanks for the info I will start doing some more research, see if I can get my costs and timetables established.

Is there any place that you recommend (preferably online) that deals in all of this? Does Everdure have an online store or will I have to find dealers/resellers?

Speaking of dealers resellers, from the insulation post on here I have been looking at getting a roll of Armaflex from Armacell (to kill the condensation problem during winter months here in LA) and boy, it is hard to get them to call you back...

[Landlubber]

....correct about the poly not going on over epoxy.

....sometimes a tie layer of vinylester resin will allow epoxy to go on over it....but try a sample first as the epoxy may not go off.

[jboswell]

will protect the wood veneers better.

Just to clarify btw, this coating is mostly for looks, I would rather have a glossy white opaque bulkhead than a plywood edged one, I don't even want to see wood. I want a little extra protection from termites and the occasional water splash, but I am not expecting a whole lot of water just sitting on these for prolonged periods of time. If that did happen I think there would be bigger problems at hand.

I understand epoxy is a better product but I am not really sure how much better I really need, after all the boat was build in 78' out of what is very likely a much less technically sound Poly resin than we have today and it is still, mostly, in good working order. The problem was what Bayliner cheaped out on, if they had simply put a line of poly resin around the hull/balsa sandwich where it met the windows, we wouldn't even be talking about this, the boat would be in pristine condition.

My concern is more with the expanding contracting nature of the wood involved and whether or not the resin, be it poly or epoxy, will be able to handle that, stronger in this situation isn't necessarily better, flexibility would be I think what I am after.

J

Originally Posted by jboswell

Just to clarify btw, this coating is mostly for looks, I would rather have a glossy white opaque bulkhead than a plywood edged one, I don't even want to see wood. I want a little extra protection from termites and the occasional water splash, but I am not expecting a whole lot of water just sitting on these for prolonged periods of time. If that did happen I think there would be bigger problems at hand.

I understand epoxy is a better product but I am not really sure how much better I really need, after all the boat was build in 78' out of what is very likely a much less technically sound Poly resin than we have today and it is still, mostly, in good working order. The problem was what Bayliner cheaped out on, if they had simply put a line of poly resin around the hull/balsa sandwich where it met the windows, we wouldn't even be talking about this, the boat would be in pristine condition.

My concern is more with the expanding contracting nature of the wood involved and whether or not the resin, be it poly or epoxy, will be able to handle that, stronger in this situation isn't necessarily better, flexibility would be I think what I am after.

J

As far as I understand you the coating is much more than cosmetically, when you point towards mold, insects and water ingress!

Epoxy is not the better product in your case, it is the ONLY one to solve your problems easy and proper.
Vinylester is not worth a thought, because it is still not as good on wood, but almost as expensive as Epoxy.

Flexibility is not what you want in a bulkhead, you want it to stiffen the structure, but that is a minor concern here. From a technical point of view there is no difference between polyester (if it would stick on the ply) and the epoxy, when it comes to the flexibility of the sheathed ply.

Gelcoat is a nonsense on any interior surface and sure not the way to go for your application. It is not easy to apply, does not give the shiny surface you ask for (you do´nt build a waxed and polished mould for a bulkhead, do you?), is NOT as watertight as you might assume, and of course sticks to wet poly only which you cannot use.

You get a much better surface when you encapsulate the wood in EP, and primer, sand, paint to the glossy surface you want.

Regards
Richard

[jboswell]

As far as I understand you the coating is much more than cosmetically, when you point towards mold, insects and water ingress!

Again though, mold/water ingress is gonna show up if there is water just sitting on the bulkhead, and if that is happening then I have done something drastically wrong. As far as insects go, I would think anything I put on the surface will stop them, a simple coat of paint would do for that..

Flexibility is not what you want in a bulkhead, you want it to stiffen the structure, but that is a minor concern here. From a technical point of view there is no difference between polyester (if it would stick on the ply) and the epoxy, when it comes to the flexibility of the sheathed ply.

I don't mean flex in the bendy sense, I mean flex in the expansion/contraction of the water in the wood from the atmosphere, it's 3/4" plywood, it's definitely going to stiffen the boat from a bulkhead standpoint. But when the temp goes up to 95 degrees down in Oaxaca or when I am sitting in the slip and winter in CA drops it to 40 degrees at night I want to be sure that the wood isn't going to crack the resin coating the bulkhead.

Gelcoat is a nonsense on any interior surface and sure not the way to go for your application. It is not easy to apply, does not give the shiny surface you ask for (you do´nt build a waxed and polished mould for a bulkhead, do you?), is NOT as watertight as you might assume, and of course sticks to wet poly only which you cannot use.

You get a much better surface when you encapsulate the wood in EP, and primer, sand, paint to the glossy surface you want.

Gelcoat is primarily used in molds, in this case I am just rolling on a coat over the base coats of poly and sanding it down smooth and going over it with some wax to buff it out. This may be a terrible way to go as I don't know the long term effects of the process, but it is easier for me than painting since I would need to purchase or rent a sprayer in order to get the same gloss finished quality.

Originally Posted by jboswell

Again though, mold/water ingress is gonna show up if there is water just sitting on the bulkhead, and if that is happening then I have done something drastically wrong. As far as insects go, I would think anything I put on the surface will stop them, a simple coat of paint would do for that..


No no, you do´nt need "standing" water to build up mold or to get moisture in the wooden structure.

Simple paint does not stop insects, that is proven.


I don't mean flex in the bendy sense, I mean flex in the expansion/contraction of the water in the wood from the atmosphere, it's 3/4" plywood, it's definitely going to stiffen the boat from a bulkhead standpoint. But when the temp goes up to 95 degrees down in Oaxaca or when I am sitting in the slip and winter in CA drops it to 40 degrees at night I want to be sure that the wood isn't going to crack the resin coating the bulkhead.

That is no issue, the wood (ply) you use will have a moisture content of about 12%. When you encapsulate that completely in EP (and there is no other material for a homebuilder) it does never crack, no matter how different the temperatures may get.

Gelcoat is primarily used in molds,
No, exclusively!
in this case I am just rolling on a coat over the base coats of poly and sanding it down smooth and going over it with some wax to buff it out. This may be a terrible way to go as I don't know the long term effects of the process, but it is easier for me than painting since I would need to purchase or rent a sprayer in order to get the same gloss finished quality.

You do´nt get a gloss finish with gelcoat! Just a expensive mess.

Obviously you do´nt understand what Gelcoat is? Nothing but poly resin and pigment, to make it simple.
It gets so nice because we polish and buff up our moulds before applying the stuff! That makes mass production easier and cheaper. But from a technical point of view it is a worthless crap.

A good filler, fairing and paint job on Epoxy gives you a better result.

Regards
Richard

[jboswell]

Ahhh, ok, definitely clear now, many thanks for your patience sir!

I am headed off to go lookup the epoxy stuff, is there any online stores you recommend by chance?

Originally Posted by jboswell

Ahhh, ok, definitely clear now, many thanks for your patience sir!

I am headed off to go lookup the epoxy stuff, is there any online stores you recommend by chance?

Sorry no idea about US suppliers, I build in Turkey and live in Germany, that does not help you.

Regards
Richard