Talk Composites - The Forum for Advanced Composites

first time using uni mould. potential problem.

http://www.talkcomposites.com/Topic2363.aspx

By andrewt1971 - 7/23/2012 1:08:26 PM

Hi

I was attempting to make a mould for a car hatch/boot and ran into what i presume are a couple of problems in that i applied the gel coat, catalysed at 1.5%,, after reading the instructions that indicated you should leave till tacky or overnight i was surprised that in under two hours the gel was dry to the touch in places with no tack at all.  At this time i did what was probably the wrong thing and decided to put the coupling coat on, which again went past the tacky stage in places before i'd noticed so i put the reinforcing on.

my question is, can you 'rescue' the job if you get a cure before the next layer goes on, should the job be abandoned or is it not a major problem?  in truth i will probably only ever pull two or three products from the mould so long term durability isnt an issue.

Thank you for your time
By Paul (Staff) - 7/25/2012 4:08:46 PM

Hi Andrew,

The Unimould system is very forgiving although as you identified you may have left it beyond the 'ideal' point you should still obtain a sufficient inter-laminar bond even days after application, so you should be fine especially if as you say it's not going to be used that many times.

I will add though (for other people reading this thread) that this is not true when using an epoxy mould making system, timing the 'tack' properly is vital to getting a good bond between layers.

I hope this helps.