Well, that got your attention.
I have a number of questions and a mixed bag of results over the last couple of months working backwards -

I have and epoxy mould, surface prepared sanded to 1200 grit wet and dry Polarshine'd coated with 5 coats of easy lease and 5 coats of Canuba wax, I thought this morning it would jump off the mould.......

Didn't stuck in various places, the gel coat stuck fused to the mould in patches delaminated from the Diolen, mould Frigged panel frigged

Can easi lease go off, I've made 12 different parts and I've never had so much pain as the last few where I have taking extra precautions, drying times between coats on the easi lease and the wax ???

I've changed to the epoxy infusion resin ??
I might have tipped a bit more hardner in there ??

Could it be curing times, did I pop it out to early ??

The mould had a talc mixed gel coat ???

Can I repair the mould with filler and sand it back down ???

Also, I'm thinking of using a 2 part silicone or latex mould with a GRP backing as my shape has complex corners.
Is there any issue's with this and epoxy infusion resin in a Resin infusion method ?

Hi Congellous,

I have and epoxy mould, surface prepared sanded to 1200 grit wet and dry Polarshine'd coated with 5 coats of easy lease and 5 coats of Canuba wax, I thought this morning it would jump off the mould.......

Didn't stuck in various places, the gel coat stuck fused to the mould in patches delaminated from the Diolen, mould Frigged panel frigged

This is a real suprise. The combination of materials you are using is fine so something else must explain the release problems. The only things this could be are:

1. Something on the moulds contaminated the release agent. Cure: On any mould that has had any other form of release agent on (wax, PVA, a different chemical release agent etc.) use a Mould Cleaner before you apply the release agent.
2. Something in the mould (or used to reinforce the mould) has leached solvent or styrene to the mould's surface. This could be if you've painted the back of the mould, reiforced your epoxy mould with polyester resin somewhere or if you've made a gelcoat repair to the mould's surface using a polyester resin, gel or filler.
3. You're trying to release the part before it's fully cured. Cure: Ensure the part is fully cured (feels very hard and has a 'ring' to it rather than a 'thud') before releasing. Trying to release parts when they're not fully cured can be incredibly difficult and can damage the mould and the parts.
   
4. You're post-curing the part in the mould at elevated temperature and melting the wax (you don't mention this and it seems very unlikely if you're concerned that your parts are under cured).
5. Finally, there is the possibility that the release agent has gone past its use by date. The main thing that effects this is how many times you've opened the containers (the release agent is high hydroscopic and will absorb moisture out of the air each time you open the container). You could try testing the release agent on a sheet of glass (ruling out any mould problems) to see how it behaves. It's almost unheard of for customers to have release agent going bad but you don't mention how long you've had it or whether it's been kept tightly sealed so these would be things to look out for.

I've changed to the epoxy infusion resin ??

This should make no difference. We use the infusion resin all the time on this release agent combination and it's bomb-proof.

I might have tipped a bit more hardner in there ??

There's the scary bit right there! The mix ratios for epoxies are not to be followed approximately, they are to be followed exactly. It's essential that you're aiming for 1g accuracy on your mix ratios, just the phrase 'tipped a bit extra' makes me shudder. If you've got extra hardener in your resin then for one it will not cure properly (contrary to some people's assumption that extra hardener will make it cure faster - this is simply not true!) because you will be left with a surplus of uncured hardener in the resin. This itself might attack your mould surface, cause the part to no cure and explain your part sticking in the mould. Get some digital scales if you don't have some already.


Please mix resins to hardeners at the stated ratio, as acurately as possible. We get countless stories of people 'adding more hardener' to cure things faster or 'just to make sure' and it really is the worst thing you can do.

Could it be curing times, did I pop it out to early ??

Possibly although the extra hardener sounds like the biggest sin. Release too early will cause problems however. See above.

The mould had a talc mixed gel coat ???

This is unlikely to be the problem unless the ratio of talc was so high that the mould surface became almost porous. I would suggest using a specific epoxy tooling gelcoat rather than a home-brewed one if you've not made this and had success with it before. Is the talc pure (for composites) or is it scented/modified medical talc? As stated, I'd avoid the home made gelcoats if you're having release problems.

Can I repair the mould with filler and sand it back down ???

I don't know what you mean by filler but if you mean polyester bodyfiller then no, certainly not. You can repair it with epoxy tooling gelcoat though, this should be no problem.

I hope this helps. There do sound like quite a few possible problems in there. The home-made epoxy/talc mould surface, early releasing and particularly the over addition of hardener all sound like on their own they could cause release problems.

All the best, Matt


Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Thanks Matt, I didn't realise the hardner was down to the gram and did think as long as it had more it would be OK