I’m looking into vacuum bagging a part I have been hand laying with a divinymat core.the consern I have is my last layer over the divinymat is 6oz cloth and I am worried the breather fabric will absorb the resin out of my 6oz cloth leaving it dry with their not being any other layers under it to pull resin to bond. Anyone have any thoughts or suggestions
Thanks
You need to have a perforated release film between the laminate and the breather to minimize the resin drawn into the breather.
As above. The use of a perforated release film/bread bag will reduce resin take-up
And the pressure. your resin viscosity, temperature, and release film are all important on how much resin you suck out of your laminate. your pressure will probably be the easiest to adjust. I usually use P3 film, a quite thick resin (Gurit ampreg 21) and about 70% vacuum at about 20 degrees to get my desired result. with slightly thinner resin like sicomin sr8500 I go to 60% vacuum. be aware not all manufacturers use the same system, P3 in my case is about a needle pinch every 10 mm, where P0 is 1mm gap every 10mm.
I will be using a low viscosity VE resin. I also have perforated film now. So if I put a bleed off valve on the vacuum line to lower the vacuum until it starts to cure. What is a sign or Indicator I should switch to full vacuum.
Don’t switch to full vacuum. Get a vacuum control valve and let that do the work, it’s way easier than trying to control things manually.
I normally pull about 75% vacuum, but you will need to experiment a bit with your resin to see what gets the best results. If you’re after cosmetics more than performance, then 60% would be better.