Hi,

I am researching and testing to find the greenest way to mould patterns. I have already tested a few materials and now asking people on this website if they have any ideas for sustainable moulding processes.

I have access to offcuts of prepeg carbon from the automotive industry and looking into using this material instead of just throwing it away. If I can make moulds out of a green material then the product made from this reused carbon is a green product. As well as this reason my conscious will be clear : )  However, I am slowly coming to the conclusion that it is impossible to make an eco friendly mould that can withstand the conditions in the autoclave for the prepeg carbon (125 celsius and pressurized).

The first material I looked into was plaster of paris. I found plaster that also had polymer in the mix (I think this would be something similar to white wood glue) which proved to be strong under both compression and torsion, but every attempt always had problems when it came to post curing up to 125•c, such as warping or cracking. I tried different mould releases, also tried adding materials to the inside of the plaster such as chicken wire, but no success. The brands tested were Hurculite and Cassini's which I think are top of the range so cant blame the material. I've never used plaster before and really wanted this to work. If anyone has any likely ideas why this material warped/cracked after post cure I'm all ears. 

After this I looked into materials that can be used for wet lay mould making. There is an epoxy resin that has come out of the surfboard industry that has green credentials. It's called SuperSap, it uses waste material from the timber world to make some of its resin. Buuuuuuut..... this epoxy can't go over 70•c so not suitable for going in the autoclave.
Flax weave is also a material I have tested. This is a plant based material that can be used instead of glass. Although it can withstand the 125•c it did warp. The test piece for this was a plate shape, so if it was more boxed shape it may not have warped. It costs more than glass so for the larger moulds I cant use it, but might do for smaller moulds.


So I am coming to the conclusion that I will have to use the traditional materials (glass and epoxy) for a wet lay mould. 
But if I use this mould many times, then the amount of prepreg carbon used inside of the mould and not thrown away into landfill will outweigh the amount of material used for the mould. So it is still a 'green' product, but it would be much better if I did find a green moulding process.
 
If anyone knows of a material / method that I should look at please let me know.  Thanks