epoxy moulding

[nedgrater]

Hi. I want to create an epoxy moulding but am not sure the best way to go about it. I have made polyester moulds and mouldings in the past, but am wondering if I can use a polyester mould for an epoxy moulding, and can I just use an epoxy resin as a gel coat?
Many Thanks Mark

[wet feet]

You should have no problems using a polyester mould for an epoxy component.You could use an epoxy gel coat,but there is only a small range of stable epoxy pigments available and the whites I have seen tend to go yellow quite quickly.The alternative is to use a two pack paint to act as a barrier and provide the colour of your choice.

[nedgrater]

Hi Wet feet, Thanks for the reply. I have also been advised a polyester mould may not be suitable for an epoxy moulding because of the shrinkage of polyester
but i'm not sure how much of a problem this would be. Maybe by heating the mould I could get rid of most of the srinkage by super curing the mold first.?.
As far as gel goes colour is not a problem, so I was thinking lam directly onto the mould, good idea? Thanks for your help. Mark

[wet feet]

It would definitely be a good idea to ensure that the polyester has fully cured before using the mould.I would doubt that an ambient temperature moulding process would cause any problem with the relative shrinkage of the materials if a new mould is used.The use of heat needs to be approached with due regard for the resin manufacturers recommendations for ramp and dwell.Direct lamination onto the mould ought to work.Good luck.

[Submarine Tom]

Nedgrater, I've done this, it should work fine.

The usual rules apply. How big are you going?

Are you using West System epoxy? Have you used it before?

Are you indoor or out? Have you considered vacuum baging your project?

Look into it if you want quality.

Tom.