Talk Composites - The Forum for Advanced Composites

Is a surfactant needed for polyurethane foam mould to reduce air bubbles?

http://www.talkcomposites.com/Topic6543.aspx

By FiftyPence - 6/16/2013 10:49:33 PM

I am trying to make a mould out of polyurethane foam LD40.  It is very similar to expanding foam you can buy from the DIY stores but this comes in two parts and you mix it up yourself.

My first attempt resulted in foam which had alot of air bubbles in it and not nearly as solid and sculptable as the example I had seen which was the basis of my method.

Do I need to add a surfactant such as silicone to the mixture of part A and part B to reduce the air bubbles in the cured foam?

Thanks in advance for your feedback.
By FiftyPence - 6/24/2013 1:31:53 PM

As an update on this, I was originally using LD40 two part polyurethane foam but it was low density rated at just 2lb per cubic foot.

I've since switched to trident foams tripor 224 which is classed as high density two part polyurethane foam and it is much better as it creates a solid much more dense foam which can be carved.