Plastic sheet that epoxy doesn't stick to?

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mikes
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Plastic sheet that epoxy doesn't stick to?

Post by mikes »

I make precured topsheets on a sheet of glass prepped with three coats of mold release wax. I wet out the outer skin of light weight fiberglass on the glass, then wood veneer strips, then a layer of peelply, then vac bag the whole thing.

Basically I'm just looking for something that doesn't need waxing and I want to stop tossing out peelply so I could use this non-stick material on both faces. Does anyone know of a plastic sheet material that epoxy will NOT stick to? Looking for something stiff like formica or thin plexy glass with as smooth a surface as possible.

Thanks
Mike S
mark
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Post by mark »

I've had good luck with Formica and Wilsonart laminates. The matte finish works good and is the cheapest finish. Not sure how it will hold up to multiple uses though.
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endre
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Post by endre »

Try out Mylar. Nothing sticks to it and you can get it in pretty stiff qualities. I have pressed skis with mylar towards the top fibreglass (no topsheet) and it peels right off leaving a mirror smooth surface.
mikes
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Post by mikes »

endre wrote:Try out Mylar. Nothing sticks to it and you can get it in pretty stiff qualities. I have pressed skis with mylar towards the top fibreglass (no topsheet) and it peels right off leaving a mirror smooth surface.
I've heard that people have used mylar so I bought some mylar from Fiberlay in Seattle and the QCM resin I have bonded to it. Where did you get the stuff you used?

Mike S
mikes
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Post by mikes »

mark wrote:I've had good luck with Formica and Wilsonart laminates. The matte finish works good and is the cheapest finish. Not sure how it will hold up to multiple uses though.
Yes but you wax it correct? I've used formica but I wax it just like I do on the sheet of glass. Wax is fine for the other skin but I don't want wax on the side that is going to bond to the core. I'll stick with peel ply if I have to but I creating waste. I don't want to apply wax, it's a pain, and I hoping to avoid that step.

Mike S
G-man
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Post by G-man »

Either UHMW or HDPE will work well for this purpose, as long as neither has been treated for bonding. HDPE is less expensive. I bought a bunch of 1/8 x 12 x 96 inch HDPE sheets on ebay for $3 each. They are very smooth on both sides and leave a very smooth finish. No release agent is necessary.

I'm not at all well versed in vacuum processes, but I was under the impression that peel ply is pretty much a requirement for surfaces that will need to be bonded at a later time... either that, or lots of coarse sanding prep that can damage composite fibers (although it sounds like your bond surface is veneer without composite, so sanding would probably be okay). Also, I thought that peel ply was somewhat reusable. Do I understand correctly that this may not be true?

G-man
mikes
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Post by mikes »

I'll try to find some, thanks for the heads up!
G-man wrote: I'm not at all well versed in vacuum processes, but I was under the impression that peel ply is pretty much a requirement for surfaces that will need to be bonded at a later time... either that, or lots of coarse sanding prep that can damage composite fibers (although it sounds like your bond surface is veneer without composite, so sanding would probably be okay). Also, I thought that peel ply was somewhat reusable. Do I understand correctly that this may not be true?
G-man
Peel ply works great but it cannot be reused since it absords resin. In my experience it's not a requirement (though it does work really well). Most epoxies will chemically bond to within 24-48 hours (according to QCM and System Three) so that's why I want to try an alternative. If I do use a plastic that will release from epoxy I'd still feel better abrading it so it wasn't shiny
mark
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Post by mark »

mikes wrote:Yes but you wax it correct?
Nope, no wax.
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endre
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Post by endre »

mikes wrote:
endre wrote:Try out Mylar. Nothing sticks to it and you can get it in pretty stiff qualities. I have pressed skis with mylar towards the top fibreglass (no topsheet) and it peels right off leaving a mirror smooth surface.
I've heard that people have used mylar so I bought some mylar from Fiberlay in Seattle and the QCM resin I have bonded to it. Where did you get the stuff you used?

Mike S
Not shure actually, I got an old roll of unknown origin. I can try to trace it.
mikes
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Post by mikes »

mark wrote:
mikes wrote:Yes but you wax it correct?
Nope, no wax.
Never tried laminate without waxing it, I wonder if there's a risidual release agent on the laminate from the manufacturing process? Have you ever used a piece more than once?

I use scraps of formica all the time for mixing up little bits of epoxy and fillers, once it's cured it never comes off, so that's why I assumed it needed to be waxed. I'll have to test it I guess

Thanks
Mike S
hadley
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Pealply reduces weight

Post by hadley »

Fiberglass Supply www.fiberglasssupply.com sells 2 weights of peelply. The light weight stuff is thinner and less expensive. It works well as long as the breather material above the peel ply is not really saturated. The other advantage of peel ply is that it reduces weight by removing excess resin. Good luck
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