Progress on the Port Fuel Tank

Made good progress on the inside bulkhead for the port side fuel tanks. Started the morning grinding the rough spots off then released it from the Formica and cleaned all the edges up. I was very pleased at easily it came free from the Formica I had layed it up on.

The bottom surface which will be the inside turned out very smooth.Here it is with the inspection port covers in place. After lining the covers up where I wanted them I drilled 1 hole though the fiberglass at opposite corners. Then I threaded those two holes in the aluminum and put the studs in. Returning to the bulkhead opening I inserted the two studs in the holes I had drilled to hold the plate in exact alignment. Then I drilled all the rest of the holes though the fiberglass.
 



There are 30 holes in each plate. The method I use to align those holes makes sure that they are all lined up right. The first holes I drilled though the plate are smaller than the bolt diameter. I enlarge the first two corner holes to 1/4" so the studs will fit though tight thus holding the plate very steady while the rest of the holes are drilled. The final size for the holes in the fiberglass is 5/16" there is not very much room for error. if the plate were to move even a little while you were drilling those holes it would not fit when you have all the studs in. Been there done that....
After drilling all the holes though the bulkhead, I cut and glued the gaskets on to the plates. Then I threaded all the holes in the plates ready to bond the studs in. The cordless drill comes in very handy when threading all those 120 holes in 4 plates.

So here is the inside bulkhead in place with all the foam strips in ready to glass. I am putting the top on this tank last. On the Starboard tank I put the inside bulkhead on last, thinking I could get better bonds on the top with the inside bulkhead off. But fiberglassing the top on from inside the tank and then having to glass the bulkhead on though the inspection ports was a real nightmare. I got it done with good joints all around but swore I would never do that again. I have a better plan, which you will read about as I proceed.

  One of the inside corners with the polyurethane foam fillet in place. I found these a whole lot easier to make than the resin and saw dust ones are. The strength is in the fiberglass not the fillet.

Hope to get the inside corners all glassed in tomorrow.