not sure but as far as i know epoxy is more rigid that vinylester... vinylester will be more chemical resistant and heat resistant in some ways

****Not quite sure why you would actually want shrinkage?
As this is racecar bodywork and you say weight is critical I would have waited the three weeks for the epoxy infusion resin. Result would be a stronger and lighter part with much less/zero print through.***




Well I need to lengthen my wheel base so with the shrinkage in length of the body it negated me from having to make changes. (long Story but it worked)

The reason why I'm using Vinyl Ester is the stiffness, Epoxy doesn't have the same rigidity as Vinyl Ester especially on the rear section where it is going to see engine bay heat.

Further more Epoxy seems to be silly expensive lately

UK supplier, nice guys too

No as yet, no. I have been meaning to do some more of my crude testing, just haven't got round to it. Certainly the tech data sheet makes it sound the goods. More info here:

Interesting, have you done any structural testing?

Warren

Carbon Copies Ltd

I love it. Absolutely no reason to go back to using Soric, it's better in every way. 

Polyester resins contain about 50% or so of styrene, VE contain a little less, like 35-50%. Adding 5% of styrene will give you roughly another 1% of shrinkage (volume reduction). Doesn't sound like much, considering those resins already shrink 5-10%, but it adds up.
Epoxies have a volume reduction of roughly 3-5%, which is 2-3 times better.
All numbers are only rule of thumb, don't take them as absolute.

Try to find epoxy infusion resin, or alternatively the lowest viscosity epoxy resin and a low viscosity (slow) hardener, that should work, too. No slots in the core, and use some post curing in the mold, then most problems should go away.

> Amorim Corecork

Interesting. I've seen it a few years ago at the Composites Europe trade show and grabbed a small box of samples but never used it myself.

Not quite sure why you would actually want shrinkage?
As this is racecar bodywork and you say weight is critical I would have waited the three weeks for the epoxy infusion resin. Result would be a stronger and lighter part with much less/zero print through.

I have done some tests in the past on the gelcoat verses paint argument. By the time you have have applied adhesion primer, base primer plus top coat there is negligible difference in weight over carefully applied pigmented gelcoat. In fact depending on who applies the paint parts can actually end up being heavier. Depending on the final colour wanted you can also just pigment the infusion resin.

Much depends on the number of layers of reinforcement, the size of the panel being infused and the thickness of the core as to the size and spacing of the resin transfer holes needed. It is also important to balance the number of reinforcement layers either side of the core, not only from a structural point of view but also from an infusion perspective. If you have more reinforcement on the mould side of the core the resin can infuse through the top reinforcement too quickly leaving the mould side reinforcement starved of resin.

Warren

Warren

Carbon Copies Ltd