GF14 glassing and sanding questions

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Rumdoctor
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GF14 glassing and sanding questions

Post by Rumdoctor » Sun Jun 10, 2018 11:34 pm

I have 3 of the 5 bottom sections inside the boat glassed with tape and cloth. I worked wet on wet but did not put the plastic sheeting over the cloth when curing. I think my glass job is okay, but there is a corduroy effect from the "threads" like a fresh groomed ski trail. Is that okay? Im guessing that doesn't happen if I use the plastic sheeting over top. When ready to fair and prime, do I just sand down the corduroy texture first? Guess I'll try the plastic method on the next 2 sections before tackling the outside hull.
Thanks



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pee wee
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Re: GF14 glassing and sanding questions

Post by pee wee » Mon Jun 11, 2018 9:08 am

The corduroy texture you see is the cotton binding threads, sand those ridges down but don't sand into the glass. Plastic will leave a smoother finish, but I wouldn't bother using it because you're going to have to sand anyway, and it's more sanding if you're sanding both epoxy and threads. The plastic won't make the threads sit lower, it just allows the resin to sit higher, not sure that's a plus in areas you're going to be fairing.
Hank

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Re: GF14 glassing and sanding questions

Post by Rumdoctor » Mon Jun 11, 2018 1:12 pm

Thanks pee wee. After sanding the ridges, would it be advisable to roll on a thin coat of epoxy before the finish work or is that just a waste?

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Re: GF14 glassing and sanding questions

Post by Reid » Mon Jun 11, 2018 2:41 pm

Rumdoctor,

Pee Wee is right. The pattern you noticed is perfectly normal. If you didn't see that pattern that would mean that you put way too much Epoxy on your fiberglass (Epoxy Rich). The goal is to use the least amount of Epoxy to wet out the fiberglass and squeegee out the extra. Too much simply adds unnecessary weight. You will then mix up some fairing compound (Epoxy mixed with Microballoons and Silica) (we sell it as "Blended Filler") and use the cotton fibers as a guide for your fairing compound as you are spreading it on. You then come back and sand to your desired smoothness being careful not to sand into the actual Fiberglass fibers. It is ok if you sand into the cotton threads.

Best of Luck,
Reid
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Rumdoctor
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Re: GF14 glassing and sanding questions

Post by Rumdoctor » Tue Jun 12, 2018 11:20 am

Ok thanks Reid. So leave the texture there and just apply fairing compound over all the glass first before any sanding. What's the advantage of using the plastic sheeting method I read about then? It just results in using less fairing compound? Curious as this is my first go, so trying to learn the intricacies.

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Re: GF14 glassing and sanding questions

Post by terrulian » Tue Jun 12, 2018 11:54 am

Peel Ply is probably what you're talking about. Some builders use it, I didn't so can't help. Google it; there are a lot of suppliers although I'm not seeing it on the BBC site. Maybe just buy a yard and try it.

On perfectly flat surfaces you can use mylar which will leave a flat, glossy surface, but peel ply will follow the curvature of the boat.
The peel ply cost isn't too bad but it isn't that cheap either. My guess is that you're going to be sanding no matter what you do. Sanding is the pretty much universal complaint of all builders but I got into it. You don't really have to sand anything too much; if you don't, the boat will float but will look crappy. :? :roll:

You do want to sand down the ridges of what you just did, as pee wee says.
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Re: GF14 glassing and sanding questions

Post by Jeff » Tue Jun 12, 2018 11:58 am


terrulian
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Re: GF14 glassing and sanding questions

Post by terrulian » Tue Jun 12, 2018 1:09 pm

Thanks, Jeff. I didn't think to look under "tools."
Tony
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