Re-coring the fuel tank floor hatch

[awthacker]

First step was to cut around the edges of the old core with an angle grinder, then pry the bottom layer of mat off the wood core. Then used a hammer and chisel to remove the 6" plywood squares. Then cleaned it up good with the grinder.

Next was the new core. I went with standard non treated plywood, 5/8" thick. I think I could've gotten away with 1/2" and it might've been a bit lighter. Used resin to glue the ply to the fiberglass hatch, then weighted it with whatever was available. Notice the 1/4" holes drilled through the wood to allow the resin to adhere well and prevent air bubbles.

Then glass mat over the wood core.