Just a quick question

[jimnmad]

I put the fiberglass fabric embedded in epoxy on the outside of my hull last Sunday. I fully intended to go out the next day before the resin hd fully cured to roll another coat of epoxy on it to smooth everything out. But, due to circumstances beyond...........it's now a week later. The workspace is relatively cool and you can still feel the fabric texture. Do I need to sand this down before i re-coat it? I'm afraid of fuzzing up the fabric but since I plan on painting it anyway does it matter? Thanks in advance for the help. This is my first fiberglassing project and I never seem to anticipate these questions until right before I want to work on it.

[landlocked sailor]

I think the problem with recoating now is amine blush. If the epoxy is 'no-blush' then it should adhere fine. However, if you sand down the fuzz, you will need fewer coats to fair the surface. If you did not use no-blush epoxy, the surface needs to be cleaned first. Rick

[NormMessinger]

If it were I, I'd wash it down with water, knock off the high spots a little but not enough to get into the glass and recoat. I've never had problems doing this but opinions may differ.

[Aramas]

I've heard differing opinions on this - some say that coating over cured epoxy still produces a chemical bond, others say no, and that you have to roughen the surface for a mechanical bond.

I hope the former are correct, or I've produced some shoddy work.

[Dave Wright]

After a quick washdown, I've found that the green 3M stripping pads (Scotch Brite) do a great job of dulling the shiny epoxy surface without tearing the glass up. They don't load up like sandpaper, are flexible enough to get into most of the little indentations, and they work real fast. They're easy to wash out when you're done. Sometimes I clip a piece into a palm sander and that works fast and easy too.

Dave Wright

[Ian McColgin]

In that situation I lightly sand to get all fair and to remove any blush. The fuzz won't hurt at all - actually increases adheasion - and won't diminish the strength. After a water wash and drying, I tack with a rag that has acetone in it, which will certainly do in any lingering blush.

It's almost always a mistake not to sand between layers of anyting, even things that 'don't require sanding' because, like the moguls on a ski run, the bumps just get bigger with each application.

G'luck

[Wild Wassa]

Aramas, would you be using BCP's epoxy? A quick test is; on a small bit of scrap put two or three unsanded coats of epoxy. Coat at about a day and a half apart. Then after they have cured, (for about 4-5 days), drop a heavy screw driver point, or adjustable spanner onto the test sheet, from about a metre. With a Stanley knife blade, try to pick-off the paint within the indentation, and around the edge of the paint fracture. You will then see whether BCP's non-blushing epoxy has chemically bonded.

Warren.

ps, You probably won't even have to use the Stanley knife blade, the interfaces will describe what happens.

[ 12-29-2003, 04:46 PM: Message edited by: Wild Wassa ]