-------The building of the fuel tank was a bit of a challenge. Somethings that shoul have been very easy, were very difficult; while somethings I anticiated to be exxtremely difficult, turned out to be fairly easy. I also had many work related issues going on, so work on the tank was very stop and go over many months. I will apply notes below where applicable and remembered.Hours: 40.0------------
My aluminum arrived slightly damaged, which appeared to come from the carrier. I informed the company I used (not mentioned here, because I really like them), who offered to replace, but I just wanted to give them the data point. I was able to use most of the sheets, and work around the bent corners. I measured everything for the main sheet parts. My idea was to make the bottom of the tank out of one piece, wrapped up in front and back. Then cut side pieces and a center baffle, and finally a top piece. I studied the side pieces for a while and studied what others had doen. Many people on line were concerned about maximizing the amount of fuel they carried, and made the outside pieces "flush" with the top and bottom, instead of having the walls recessed (for better rivetting). Its all a choice. However, after calculating the difference in fuel to be roughly about one half gallon, I thought there was more benefit to getting good rivets and a stronger tank. Also, on my Taylorcraft I have 12 gals in the main tank, whih is all I mainly use, even on cross countries, and thats about the limit of my butt. Later on I will measure and find this tank will hald just over 13 gals, and with the same engine, although it won't have the same performance, will challenge my back side about the same.
For the NPT fuel fittings and fuel neck, I decided to used weldable fittings and pre-weld them to plates that could be rievetted onto the tank. I did this for several reasons. First, although certified as a welder, I am not that good and know I would blow thru too many times. Also, it seemed a better way to ensure fewer leaks.Located where I wanted the fuel fittings to go and the filler neck. I planned to put in two fuel fittings, one fore and one aft, both on the starboard side of the tank. This should keep the line running from the forward to the read away from the head of the pax when entering and exiting the A/C. I also fitted another fitting for the stearman-like fuel guage to be installed later.Starting the pro-seal process. What a mess that stuff is, but holds tenaciously!Once all parts were made and fitted, I mixed up the pro-seal and started to rivet everything together. I did this all at one time. The pro-seal, as is well documented, is great stuff, but a little tricky to work with. I don't care how clean you try to be, this stuff gets everywhere. Its like working with malaises that runs and sticks to everything, making annoying strings that go everywhere. It doesn't set quick, so the best thing to do is taking your time, work slow, and change gloves and spreading tools often.
Once all the riveting was done, I did fashion a pair of wire cutters into snippers and snipped off the small ends of several rivets, that had broken off too high. These were going to cause a problem with the fitting. Once snipped, I covered each rivet head with a good amount of pro-seal.
Once the pro-seal had a chance to fully cure (I gave it about 3 weeks while I was travelling), I applied some gloves and pressurized the tank over night. Seemed all good.After a few more weeks, I again pressure tested the tank by filling with soapy water and again adding gloves and air pressure. Again, not leaks, and the test revealed the tank capacity at just over 13 gallons.
I then started to re-fit the tank into to center section. To find the exact place for the fuel valves to fit thru, and to see where the tank was resting on the bottom, I sprinkled bath power in the section, then dropped the tank in, it left perfect impressions where the holes needed to be cut. It also show locations of possible rubbing, so I glued in strips of nylon material to act a padding to the tank until I was satisfied with the way it fit (assuming at full capacity).Taking all measurements into account I could, the only major issue I ran into was that the finished tank was just over an 1/8" too tall. My options were to, change the center section, rebuild another tank, or make a slight modification. I thought everything looked good and was built well, so I decided not to rebuild or change the center section. Instead, I decided to make a cover for the top of the tank (so the rivets and bumps would not show or hurt the covering cloth, and this cover could also act as the tie down strap for the tank. I fashioned another piece of aluminum, bent it to fit over everything, glued to plywood to the center section for smoothness and made some tie down straps for the cover itself. With a little bit of work, the whole tank can be removed (if ever necessary). The result si that there will be a small, about a 1/4" hump on the top center of the center section, but the cloth covering should blend in well.Fuel tank cover complete, being installed.Showing the padding strips and hole alignments, and cover tie-down pieces.Final epoxying (with west marine 710 mico-balloon additive) smoothing and fairing.