Talk Composites - The Forum for Advanced Composites

Best molds for PU without silicone

http://www.talkcomposites.com/Topic15277.aspx

By S Dexter - 2/27/2015 12:23:16 AM

Hi,

Im fairly new to this. Whenever I see polyurethane cast, it appears that silicone molds are used. Is there any alternative because I am trying to cast a large shape that is only 1cm thick. The overall PU content would be 2litres, but the volume the mold would take up would be 86litres (which makes using silicone very expensive!!). I can machine the molds from polystyrene. Could this be covered in epoxy and then used as a PU mold?

Cheers,

Markie
By matthieutje65 - 2/28/2015 12:42:18 AM

Like warren says, use a good release agent, silicone is selfreleasing (which is nice if you want to cast a lot of PU parts) 
Silicone has the advantage as well it is flexible, making it possible to release locking parts due to their shape in the mould. 
But if you have release agents, and nice moulds it shouldnt be a problem