Hi all,

I have a mould that I made with CS25 Silicone rubber of a headlight part,  I'm hoping I can apply a coat or two by brush of EG60 Epoxy Tooling GelCoat in the mould,  and then back it with EMP60 Epoxy Mould Making Paste to a thickness of 2cm,  to harden the structure.  Have any of you tried this?  Do you think this will work?  As the CS25 Silicone is quite pliable and Silicone ( as silicone doesn't stick to anything! ),  I should on theory be able to de-mould my mould.  But would there be some sort of reaction between the two products?

I just need a temporary prototype mould for testing purposes.  This is the mould I'm hoping to apply the EG60 in,  and then the EMP60 mould paste  >>



Usually I would use 'Vac Cast Epoxy Casting resin', but I haven't got any of it in stock right now ..........  but I do have the EP60 and the mould paste.
Besides,  I think that this would be quite an interesting way of making vacuum forming plugs,  as the plugs themselves would be hollow.  Which is great for vacuum forming as you need to drill air holes in your moulds.  A solid block of Vac Cast resin is quite difficult to machine holes in!


TURK
T4 Concepts

MY concern would be movement during the process. If you apply the gel nice and thick and do a couple of coats and are careful not to press too much on the putty, then you should be ok.  However be prepared to chase fisheyes all over the place - silicone although great to release from, is very hard to get a coat of gel onto.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Many thanks Warren,  I always respect your input  
I find the CS25 quite firm actually,  and the mould is in a solid wooden box right now,  but you've mention just about the same thing as Matt did when I phoned my order through this morning.  So I'll try to be as gentle as I can while pushing the mould paste in.  Very good point on brushing the GelCoat onto the silicone mate,  hadn't thought of that!

Would there be anything that I can brush onto the silicon first to make the application of the GelCoat easier?
Liquid soap,  for instance  ( washing up liquid ),  as it's quite good at removing surface tension.

Anything's worth a try for the correct results.  I'll give it a go mate  


TURK
T4 Concepts

Its the lack of surface tension that causes the issue so soap wont help.  You want surface tension to help the gel stay in place.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant