Hi guys, I was wondering if someone could clear something up for me as I've read conflicting information and now  I have a project where I need to know

First, when you say "made using polyester resin" is that the gelcoat or tooling resin?

My answer concerns gelcoat.

Maybesomeone else will state the opposite, and that will only be good for the discussion,
but I say it will work fine as long as the moulds are not brand new, if all the styrene has "evaporated"
and you use a suitable release agent it will work.

Maybe my opinion is flawed coz I have only done this on small parts / molds (20 -30cm2),
and huge parts have more "stick".
But I had no release problems and no surface damage in the molds.

http://motoform.blogspot.se

Very good question, I would imagine he will have used a gel coat. The situation is he is very experienced with fibreglass components but doesn't have the equipment to vac bag carbon parts which is why I've been involved. I'm going there Tuesday to get all the info.

I'm interested in the answer to this as well. I'm using EL2 infusion resin and PVA as the release. It's tough to get the part out with PVA and I'd rather use easy lease and or wax but not confident without one of the guys here saying "yes that's ok"

It will be fine.  I routinely use polyester (general not tooling) to make molds that I've used with EL2 under vacuum.  polyester molds usually need conditioning or sealing prior to first proper use.  I've used both wax and easylease with these molds both with excellent results.  You will run into issues if you bake the mold though

These side scoops came from a polyester mold and are EL2.

Cheers, nice looking parts.

I think I'll easylease then wax and see how I go on. the PVA is a real pain. I don't need a high gloss finish anyway for this and I can always polish a little.

Plenty of coats of easylease (about 10) prior to waxing.  Just to make sure

Let us know how you get on.

Hi Ajb

All of my molds are polyester and I have absolutely no problem making epoxy parts, or polyester parts. I have wet layed up and vacuum bagged and infused in the same mold.

Sometimes I wax and use PVA, other times I just wax. I also use a release agent called ChemTrend which I think is about the same as the EZ lease.

One error I used to make in waxing was that I never read the instructions. You must wax buff and then wait for the wax to cure hard before applying the next wax coat. I would wax, buff and right away put on more wax buff and so on until I had 6 coats, or so I thought. What I really had done is wax buff and then when I applyed the second coat on right away I was removing the uncured first coat and so on. When I thought I had six coats, I really only had one coat. This made the part a little hard to release but it would release.

Hope this helps.

Fred

Thanks for that Fred!

listen man at my country casting epoxy clear doesnot exist so i do polyester molds and polyester casting , the best thing to use ever is pva, i always do , if i want to bake it and if im afraid that it wouldnt demold cause its going to be hot due to the fast cure for some special parts, i use 2 or 3 layers of pva , and go for it with a 100% guarantee that nothing will happen

here is a pick for a part i made using this method



best regards mhd alghoul mhdghoul@hotmail.com youtube channel :atmospherejo link is http://www.youtube.com/user/atmospherejo?ob=0&feature=results_main