Anti fouling directly over glass?

[damies]

Hi All,

Background:
I have a older boat (see sig) that is constructed by the glass over ply method, in some sections it appears that where repair work has been done, the anti fouling was painted directly onto the fibreglass without any form of undercoat.

Questions:
1. Is this ok/normal?
2. When I redo the anti fouling should I apply some form of undercoat to this area before the anti fouling, if so what's recommended.
3. any potential problems / pitfalls / issues?

I'm not sure how extensive this is yet, just something that my step dad noticed and rang me about, cause it didn't seem normal to him.

any comments appreciated.

Dave.

[zz4gta]

Should be gel coat, not glass. I had mine sanded and painted. No primer or barrier coat. Not the way you're supposed to do it, but it works. This winter, I'm redoing the bottom to fair it and repaint. Havent decided if I'll use a barrier coat, but I think a primer would be called for at the very least. If you don't care too much about the boat, just sand and repaint.

[damies]

It was described to me a just fibre glass and resin, with anti fouling painted straight on, when you rub the anti fouling you can see the glass underneath. I will try to get some photo's tomorrow.

I don't remember seeing gel coat anywhere (did they even have gel coat in 1972?)

Dave.

[scottyt]

dave when you get pics you need more posts before you can post them. then you need to use a photo host site and link them here.

also yes gelcoat was around in 72. if it had no get coat the surface would be rough and you could see either the weave of fiber glass cloth or the random pattern of chopped strand mat glass. if its smooth like say your bath tub it has gel coat.

as for the paint, first they probably faired ie used a filler to fill the weave of the glass cloth because your boat is glass over wood. which may or may not be gel coat, it might just be resin that was thickened. alot of boats just had the bottom paint right on the gel coat or the fairing. it is nice to use a barrier coat under the bottom paint to help prevent water intrusion thru the glass into the wood.

if you want more info search on barrier coats

[damies]

I thought only 10 posts needed to post photos? I posted in the sunrise/sunset thread, seemed successful.

I'm told it's only in sections, probably where repairs have been done, I'm guessing that it is thickened with resin, but will know more tomorrow.

I will look into the availability of barrier coats locally tonight (I'm at work now, good thing my boss doesn't sail).

Thanks, this is useful info.

Dave.

[scottyt]

your right it is 10 but for some reason i thought you had less than 10

i dont know brain fart

[damies]

Originally Posted by scottyt

your right it is 10 but for some reason i thought you had less than 10

i dont know brain fart

NP were all human

[xsboats]

One of the reasons that so many glass over ply boats fail is the use of polyester resin in their construction. As poly does not penetrate and bond well with wood, it must be mechanically fastened to the wood [look for staples or screws]or laid up so heavily that there is a glass hull outside of the wood hull. Due to weight, it is doubtful that this was done on a tri. Most are therefore built using epoxy , which woud need an epoxy primer to get paint to adhere well.

[damies]

Ok, got some pic's, second one not so clear.

One of the good things about being in Australia, apparently polyester resin wasn't really ever used here, so almost all boats here were made with epoxy. I can't remember the reason I think it was availability, but when I was researching Wharram's I came across a thread that explained that polyester basically wasn't used in Australia. So I doubt that's an issue here.

It looks to me like it's epoxy resin that's been thickened to get a smooth surface, then anti fouled, the anti fouling has come off with rubbing. Do the photo's make it clearer what has happened?