Regular epoxy for barrier coat?

[paxfish]

I have a small area that I have repaired near my dagger boards on a boat that stays in the water all year. The boat is cored with western red cedar and has two layers of glass on each side. The non-affected area has a few coats of interprotect2000 and then ablative bottom paint.

Can you simply overcoat my repaired area (Maybe 3 sq ft) with epoxy resin before painting and have an effective barrier coating? Perhaps add a bit of cabosil to thicken it up?

[Cheechako]

It's the only thing I've ever used for the first layer on fiberglass. If it sets up completely prior to bottom coating you must sand it though.

[model 10]

Big timers seem to be using both these days. Thickened resin and then primer.

[paxfish]

Thanks Guys.

[Scout 30]

I would not thicken the first coat. If anything you want it thinner to get a really good bond with the wood. I assume you are going to glass it before bottom paint.

[first wind]

Originally Posted by Scout 30

I would not thicken the first coat. If anything you want it thinner to get a really good bond with the wood. I assume you are going to glass it before bottom paint.

i could be wrong but, it sounds to me as if the question was about using epoxy resin to replace the gel coat on a fiberglass boat. sounds like the boat is cored with wood but, fiberglass nonetheless.

...also...

i would imaging one would have to glass the bottom of a boat before bottom paint as it would do little good to put the bottom paint on and then cover it in fiberglass. that's just my thoughts on that. anyone else think that it's a pretty much foregone conclusion that you have to do glass work before bottom paint?

[tinkrman69]

If you glass with polyester and want to barrier coat it with epoxy there is no problem. Keep in mind that the reason polyester is porous, is because it has solvents in it, when they evaporate they will leave holes...small tho they may be. if you put solvent in epoxy it'll do the same. if you put cabosill in the epoxy it won't be solid and can saturate too. if you need to use thickener for fairing then coat it after sanding with a couple coats straight epoxy resin and then then lightly sand and bottom paint. barring in mind not to sand through the final coats of epoxy. Many people try to stretch their barrier coat by thinning and can't under stand why they still get blisters.

[fatherchronica]

I only use EpoxyUSA epoxy for waterproofing. He swears that it will be 100% waterproof, and I have not seen that claim elsewhere. It is also really easy to apply. I have done blister jobs on a few older boats and it seems to be a superior product to me. My current boat had been previously repaired with Interlux epoxy barrier coat, the gray stuff, and had about 3000 dime sized blisters about 5 or 6 years later. Maybe my current repair will only last that long, I will see. But if it does not you will be able to read my attacks forever after.