Hi everyone

I haven’t used Fibreglass for many years so still re-familiarising myself with the process and hoping to learn about Carbon on the way. Apologies if my question is a little lame.

I recently made a fibreglass Air box (plenum) mould for my car.

I hopeto make the final air box from Carbon, but as an experiment I thought I would just hand lay Glass cloth and Polyester resin and if that worked I was going to attempt a hand layup using hightemp Vinylester with Carbon.

It’s important that its light weight as it will only be held onto  the throttle bodies using hose clamp.

Anyway, the air box has a two of very tight radius bends that go right around the bottom edge and I couldn’t stop the glass cloth from lifting away and lave a void between it and the Gelcoat.

I think I need to vacuum bag  and use air pressure to keep the glass cloth conforming to the tight corners.



I once heard that polyester would boil if exposed to a vacuum Is this correct?

Can I use a vacuum bag with polyester resin?

Any idea’s what the bag should be made of to avoid sticking to the poly?




Any thoughts and opinions would be appreciated 


Thanks in advance

Sam

i think the confusion of polyester boiling under vacuum with the fact that the vacuum is removing the trapped air in the resin liquid.

water boils in a vacuum at something like 20deg c

polyester is ok for infusion so you'll be fine for that

It's the styrene that can boil, when using vac with polyester I always use 0.8 bar, whether for infusion or wet lay