Well, no replies her yet, so I made a couple of two part molds. I lay up on the inside with staggered overlap, then bolt the halves together and apply 1", 2" 3" and 4" bonding strips internally across the split line. Then I applied some perforated release film and vacuum bagged.
The part had some pretty severe wrinkles inside. I don’t care about a smooth visual internal surface, just one that has no wrinkles and/or can be sanded smooth without compromising the structural integrity.
I used an Airtech perf with the smallest holes (3/4" stagger) and Air tech tube bag film. As vacuum was applied, I pushed the film into the inside. (is that my mistake?) I think the bag film pulled the wrinkle in the layup. I also had every other issue in the book, minor bridging in the corners, a few bubbles in the bridge that did not pull out.
I was happy with the restrictive nature of the perf and although I pulled 30" vacuum, it did not overly dry the part. ((haha, maybe it is because the breather got saturated) Vacuum was held for 12 hours and the part cured in a hot box at 100F for the last 6 hours. Still flexible, it was post cured after de-molded at 220F.
How can I prevent wrinkles from bunching up the glass? Options: I have some smaller tube that can be pulled though the inside, but looking at the curve at the end, it will not be conforming well either, Just do a layup and not bag, but I want to eliminate the small bubbles in the layup, will just rolling do that? Since it is a 360 degree part, will the layup separate from the mold if I do this? Or should the layup in the mold be constantly rotated until cured?
Can some you you experts actually post a reply, please.
