Hardpoint Layup Part I

This weekend I decided to do some work on the LG bulkhead hardpoint layup. I cut 5 more plies to get to the total of 22 plies needed for the layup. I laid out the paper template, the plastic and the peel ply prior to the first layup. I had used masking tape to hold the edges when cutting each ply, so I was confused when I started having a hard time getting the fibers lined up with the paper template. The second ply was even worse. I stood there scratching my head (figuratively - you don't want epoxy covered gloves anywhere near your hair) before I realized that I had cut the last 5 plies to 8" by 12", the exact dimensions required for the finished layup. I knew it was going to be almost impossible to get the edges to line up correctly with the undersized pieces, so I switched to using the bigger plies that Steve and I had cut earlier (with a 2" margin on each side). They were a LOT easier to keep the weave lined up on.
A lot of builders ended up with layups that were too thick on their first try, and I wanted to make sure that didn't happen with mine. I made sure I used the hair dryer with each ply I laid up, and let each ply pull up epoxy from the ply below.


I started to see a ridge running down the layup, and noticed that it was directly over a crease on the 4 mil plastic I had laid the layup over. I couldn't believe that a small crease like that would show up all the way through heavier plastic I had used over it, as well as through the peel ply and several layers of heavy wet fiberglass. I cleared off another section of the work table and moved the layup over to it to get away from the crease.




I was baffled by some funky looking round spots that kept showing up on the workpiece before I realized that they were simply where I had pressed my fingertips into the glass doing the layup.








When I finished laying the oversize plies, I decided to trash the undersized plies I had made and cut and laid up new oversize ones. I laid peel ply and plastic over the top, then laid a square across two 1/4" plates to check for thickness. I was surprised to see that the layup was bit too thin instead of too thick. I added the another oversized ply and checked again. It still looked too thin, but I saw that the square was resting on the tape around the edges of the layup (I didn't scissor trim the plies) and figured that I was probably the cause.



When I cut the edges off the layup the next morning, though, I found that it was just shy of 1/4" thick.