I started laying up the plenum tonight. I’m starting with two layers of glass because I’m going to have to narrow the inlets a bit and create little “ears” out the outer ends to attach the plenum to the baffles. I’ll layup a couple of additional layers once I’ve established the final shape.
I had been considering buying the equipment to do vacuum bagging, but it’s fairly expensive and I don’t expect to do much of it. After thinking about it a bit though, I stumbled on a really cheap alternative. This is one of those Space Saver storage bags. Most of the bags they sell are too small, but they sell some larger bags labeled as hanging bags, the “suit” sized bag was perfect for the plenum and cost around $10. The material isn’t stretchy, so you’ll have to coerce it into corners, but there’s enough slack to do this. Over the two layers of glass, I added a full layer of Dacron and a couple of layers of paper towels to absorb excess resin. I then used our vacuum cleaner to suck out all of the air. This worked surprisingly well, and the vacuum was still maintained the next morning.
