Talk Composites - The Forum for Advanced Composites

Help - casting didn't release from mould !

http://www.talkcomposites.com/Topic36325.aspx

By ChrisC - 4/22/2020 10:41:42 AM

Did a casting using filled epoxy into an aluminium mould. Used plenty of coats of Easy-Lease but it was well and truly stuck and had to chisel / grind it out. A few queries if I may : Has Easy-Lease got a shelf life ? This was several years old. Because it was cold and I was in a hurry I used a hairdryer to speed it up - and I didnt leave it for an hour before casting - wish I had now. Should I persist with Easy-Lease (is it suitable for aluminium) or swap to PVA ?

By Warren (Staff) - 4/23/2020 4:09:37 PM

Yes that also wouldn't help. If the resin is slightly green, it really can grip the mould making demoulding difficult. You might find the large aluminium volume compared to the cast wicks out a fair bit of the heat that normally builds up as epoxy exotherms.  In doing so, it will slow the cure down so you can end up accidentally demoulding too soon despite following recommended demould times.