This evening I finalized the assembly of the fuel tank. What a messy and smelly project. I am glad I will not need to mix up too much more Pro-Seal. The stuff is messy, gets on and sticks to everything and really has an unpleasant odor. I started by checking and prepping the mating surfaces of the tank lid, the tank top filler flange, the holes at the return line clip attachment points, the sending unit and the sending unit support ring. I discovered I had not prepped the top of the edges of the tank lid. Because I will be putting Pro-Seal under the rivet heads I determined I should prep the top of the lid so the Pro-Seal would adhere a little better. I have been cautioned by my co-pilot that the fuel tank had better not leak! After making sure all of the surfaces had been properly prepped, I wiped down all of the mating surfaces with MEK. I set everything aside and proceeded to mix a batch of Pro-Seal. I used the bottom portion a paper cup for mixing the stuff in. I used the digital scale to portion out the sealant and the accelerator. The Pro-Seal has a very distinct odor and it is strong. I could have made this final assembly last Friday evening, but because he had our monthly family dinner and a temple preparation class at our home Sunday evening I didn't want the house to smell bad, as it does presently. From past experience the smell will linger for days.
My first step was to attach the tank top filler flange to the top of the tank lid. I then spread Pro-Seal on the top flange of the tank sides and placed and clecoed the lid on the tank. The Pro-Seal is really messy and it was not really easy to get the first couple of clecoes in place, but after I got the lid aligned they went in fairly well. I installed rivets on the forward edge of the tank lid and took a picture. It didn't turn out too well. I finished installing the rivets in the lid and took another picture.
You will notice from the picture that I installed the clips holding the fuel return line to the top of the tank with rivets. The end of the fuel return line is now centered in the filler neck.
The next step was to attach the sending unit support ring and the sending unit to the front of the tank. Before doing so I spread Pro-Seal in all of the upper corners of the tank to make sure they were all sealed. Next I installed the sending unit to the support ring and then attached the support ring to the tank, Following the advice of several RV-12 builders I attached a ground wire to the sending unit. I put Pro-Seal under all of the screw heads attaching the ring and unit to the tank. However I did not put any sealant under the head of the screw attaching the ground wire. I put Pro-Seal in the nutplate and I hope that sealed the screw well enough. I don't want to have a leak problem, but I also want to make sure I have a good ground for the sending unit or it will not work. I now need to let the Pro-Seal cure for a week and then test the tank for leaks. I am keeping my fingers crossed.
