Now for the tricky part. Since this tank lid is far from flat, I can't just make flat stock to use for the inspection
port plates, it wouldn't fit. The tank lid has a good 1/2" low in the middle, because that was the shape of the original tank. So I must build custom inspection
port plates in place. The new setup will have a large port either side, one with all the fittings, the other strictly for inspection and a bi annual hose out. So I lay out the marks for cutting the ports
, and the marks for the new plates with 1 1/2" of overlap, on the tank lid. Then I cover the layout with cheap
packing tape as a release agent. The layout can be seen through the clear tape.