Introducing - Voodoo Auto Kits.

[AshG]

Originally Posted by MikeB

its less labour as Mark says, I'm no expert but with a traditional mould you have to apply the resin by hand then layer the FG then layer etc, very messy.

Where as with bagging it you lay the FG in the mold seal it in a big vacuum bag and use a pump to suck all the air out. The difference in pressure between the atomosphere and zero pressure vacuum is used to pull resin through the FG. If you get it right it can save time and up quality.

yep thats all well and good but you need a significant amount of heat to set of the curing process on prepreg, the nature of its design is that you warm it up to make it flexible to shape into the mould then you bag it, stick it in the oven which starts the curing reaction. the epoxy is already in the matting the vacuum have very little effect on pulling the resin through as its already in the matting, the true reason for vacuum bagging is that it pulls the matting right into the mould and eliminates all the micro air bubbles in the resin. (epoxys are very prone to bubbling). if you don't need the ultimate strength in the part you are much better off using a polyurethane resin as its a lot less prone to problems.