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fill coat answers (just 1)
By:Paul Jacobson
Date: 8/22/1999, 9:19 pm
In Response To: fill coat questions (3) (Ashley Goddard)

> I am building a Pygmy Coho and have fiberglassed the outside of the hull
> and completed one fill coat. When I did these coats, however, I had a lot
> of bubbles come up and although popped them all with a foam brush, the
> outlines of the bubbles remained. I think perhaps these are called
> craters. These will likely fill in with my final coat of epoxy, but my
> first question is: should I use a Surform to knock down the edges of the
> "craters" before I do the final coat? I can't sand, of course,
> because there isn't enough epoxy on top of the fiberglass to do so without
> cutting into the cloth.

> I am going to wait to do the last fill coat until this evening when the
> temperature begins dropping in hopes this will prevent more bubbling in
> the last coat.

> Also, I put on a "sacrificial layer" of fiberglass tape along
> the keel with my first fill coat. It looks fine, but I had some trouble
> getting it to lay flat over the keel and had to paint on more epoxy than I
> think I maybe should have. It began dripping down the sides a bit and I
> kept it fairly clean, but there are a couple of drips that I missed. My
> second question is: should I worry about these drips now, or just do the
> final fill coat and hope it evens out? Or will it even out or is there
> going to be unevenness that will have to be sanded out before varnishing?
> Basically,when is the best time to address this problem?

> Finally, where the keel begins to curve up, there is air beneath the
> fiberglass tape that I should probably fill with epoxy. Should I drill a
> hole through it and do that now, or should I simply cut the tape back to a
> spot before the keel begins to curve up. I guess I don't need a
> "sacrificial layer" where the boat probably won't be hitting the
> beach anyway.

> Thanks for reading. Sorry such a long message. Pygmy not open today :)

The general answer is one you have probably heard before: Fix the problems now and the won't continue to annoy you later.

A surform is overkill. Wrap a sheet of fine grit sand paper around a block of wood, and gently go over the rough spots and craters by hand. You'll knock down the sharp edges and raised areas, and the runs will show up as solid matte lines that are a bit higher than the fabric. Lghtly sanding by hand, it is unlikely you will cut through enough to even reach the actual fabric, which is already pretty well encapsulated in the resin. Knocking down the peaks at this time, and between each successive coat, keeps them from telegraphing through two or three more coats of resin. A light sanding like this should take barely twice as long as the time you will spend sponging off the water and grit after each paddling outing. I'm not talking about spending a lot of time on this. A couple of gentle passes with that sanding block and go on to the adjacent area.

The runs won't even out by themselves. Take care of them before you put on an additional coat of resin, or you will have to later sand through that 2nd coat as you work on leveling the run -- and then you'll end up doing a touch-up job with more resin in that area.

The spot where the keel curves up is going to be a `high wear' area. Don't uncover it if you already have it covered. Fill the void now. Your regular resin is fine, or if you want a quicker setting repair, get a 5 minute epoxy glue in those siamese tubes from the hardware store. Fill the gap tonight and sand it smooth in the morning.

If you have to open up a spot to get resin into a void, it is better to do it now, while you only have to cut or poke through 1 layer of resin and glass. If you put off doing it you will have to poke through 3 layers of resin and 1 of glass, and then sand it and refinish the spot.

Solve your porblems as you find them and you won't have them waiting to bite you as you get to the end of the project.

Hope this helps.

Paul G. Jacobson

Messages In This Thread

fill coat questions (3)
Ashley Goddard -- 8/22/1999, 3:47 pm
Re: Getting rid of drips
Tom Farre -- 8/23/1999, 2:20 pm
Re: Getting rid of drips
Hank -- 8/23/1999, 10:23 pm
fill coat answers (just 1)
Paul Jacobson -- 8/22/1999, 9:19 pm
Re: fill coat questions (3)
David Bryson -- 8/22/1999, 4:20 pm