I have my CNC milled PU foam from my 3D files all cut out and looking great.

Do I coat them in epoxy laminating resin direct onto the foam ?

Then I have a more hard wearing surface to build up my release agents to then eventually resin infusion in Epoxy FRP also. 

I'm concerned that the patterns are very valuable and wonder if the precaution of taking a mould of these as they are, would PVA work on the foam as a release ?

Any advice ?

Hi Congellous,

Do I coat them in epoxy laminating resin direct onto the foam ?

Yes, you should add a layer of epoxy and normally a layer of lightweight woven glass (we really like using 163g 2/2 Twill Light Weight Woven Glass for this purpose). The best type of epoxy would be an Epoxy Coating Resin - these cure with a harder, cleaner surface than many epoxies and so are easier to flat and polish to get a really good finish on your pattern prior to release coating and taking moulds.

I'm concerned that the patterns are very valuable and wonder if the precaution of taking a mould of these as they are, would PVA work on the foam as a release ?

PVA alone definately won't work as a release agent on the PU foam so I would strongly recommend that you don't do this. The best way you can protect your CNC machined pattern will be to coat it in epoxy and a thin layer of glass fibre to make it much tougher and more resiliant.

All the best,

Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales