The basic fuel tank was fabricated in Part I. The outer top and a finishing strip around the upper edge, fill hole and outlet pipe are required to complete that tank. Rather than finish the fuel tank I decided to bring the water tank to the same point as fuel tank and then finish both.
Water Tank: I already had a good start on the water tank because all the holes in the end pieces had been drilled using the fuel tank end piece as a drilling template. The next step was to drill the holes in the side pieces. Since the two sides are identical, they were tack soldered together so that all the holes could be drilled at the same time. It turned out that one side was slightly taller than the other so that after the two were soldered together, the edge of the high one was was filed down until both were equal height.
The hole drilling went pretty well and was completed in a couple hours with only a couple broken bits. It's a good idea to get a dozen 1/16" bits for this project. Once the holes are drilled it's back to the drill press to remove the burr on the exit side of each hole. I used a 1/4" counter sink for the deburring job. After using the counter sink a sharp wood chisel was run over the plate to removal any remaining small burrs.
The next step was to install the upper and lower rows of decorative rivets on the four panels. On the fuel tank I slipped the rivets into position, soldered them and then flattened the ends. This time I tried something different ---- inserted the rivets, cut them off as short as possible and then flattened the ends with a hammer. I hold the punch with the recess for the head in a vise pointing up, position the rivet head in the punch and use a small hammer to pound on the end of rivet shank to flatten it. One of the problems I found was that it's difficult to hit only one rivet with the hammer --- the 0.2" spacing is too close. (If an adjacent rivet is struck, it'll likely be knocked out.) This problem was solved by inserting every other rivet --- it was then easy hit only one rivet at a time. Once the first set of rivets were flattened, the remaining holes were filled and rivets flattened with out interference to or from the set already flattened.
Most the rivets on the fuel tank were a loose fit in the 1/16" holes. Some of the holes on the end plates that I drilled were such that the rivets were also a loose fit. This caused a problem if a couple dozen rivets were inserted and then the plate turned upside down to cut off and flatten the rivets --- the rivets fall out. This was solved by covering the heads with masking tape and then peeling the tape back one rivet at a time to put the head in the punch.
OK, why didn't I buy shorter rivets so I didn't have to cut them off? The real reason is that I wanted to buy only one size and I thought I needed the 1/8" to join two plates. However, if one has to dive in the rivets as shown above, anything shorter than 1/8" is probably too short to grasp with the needle nose pliers. In fact, the 1/8" is really too short to join the two .055" thick plates because it leaves only about 0.015" for clinching. Hanson Rivet suggest 0.062" clinching allowance for 1/16" rivets. The length seemed to work fine for me and since I ended up soldering everything, I doubt if they're be any problem.
Another question --- why didn't I drill the holes slight larger so that I would need to drive the rivet in? Turns out the next size number drill made the holes sloppy. I was very happy with the results with driving them in, even if it did take a bit more effort.
Some 600 rivets later the top and bottom rows (except at the corners) were all in place and flattened. The reinforcing angles were then cut, clamped to the sides or ends and the sides or ends used as templates to drill the 14 rivet holes for each angle. The angles were then riveted in place and soldered. The photos above show the four water tank panels at this point. The markings on the inside of the panels in the right photo are to help me match the sides and end panels.
The ends were attached to the sides with a few #0 screws and then the rivets in the seams joining the ends and sides were installed. A half dozen rivets were done at each end of each of the seams joining the ends to the sides. The area near these rivets were then spot soldered. This was repeated this until all four seams were done. This provided stability to the unit. The remaining rivets were then installed in the seams, the seams soldered with the iron and then heated with the torch to get good flow into the seam. Next, the bends were modified at a couple of the corners by pounding on a block of steel placed on the panels so as not to ding them. This corrected the angles to 90 degrees. Next one corner was pressed to bring shape from a parallelogram into a rectangle. The width of the tank is 12 3/16", a bit wider than planned but OK since the floor is 12 7/16", slightly over the 12 3/8" specification. The length is 22 3/4", right on specification. Next time I'll move the bend lines out 1/16" on each end and cut the sides about 1/8" shorter. The final step was to install the missing rivets in the top and bottom rows at the bends.
The top and bottom were next. There will be two tops like with the fuel tank: the lower top soldered in and the upper finished top secured with a few screws. Large holes were cut in the lower top for access to the tank. Angles were riveted and soldered to the center of the lower top for additional support. The holes were cut with a saber saw --- and a little rough.
The inner top was installed first so that there was easy access to the under side for soldering. The iron was used first and care was taken to make sure solder flowed onto both the top and sides. The joint was then carefully heated the joint with the propane torch so that the solder just started to flow. This smoothed the surface of the solder and also caused it to flow into the joint. Some solder did flow through and stuck to the sides just above the top. This solder was easily removed with a burr in the Dremel running at a relatively slow speed.
The bottom was then carefully fitted with the smallest possible gaps. The tank was positioned bottom up, the sides clamped in where necessary and the bottom was then spot soldered a half dozen or so places to hold the bottom and sides in position. The tank was then turned over and positioned on a flat piece of particle board for soldering. The seams were fluxed and then soldered with the iron. The iron makes it possible to get some solder up on the sides and coat the stubs of the lower row of rivets. Next, the seam and just applied solder was fluxed again and then carefully heated with the propane torch. This caused the solder to flow into the seam and also smooth the surface of the solder. The second fluxing assured that the solder would flow into any uncoated surface. The next step was to test for leaks. There were two small leaks; one in a corner and and the other in the middle of one end. More flux, a little solder with the iron, more flux and a quick heat with the torch fixed them.
The bead was added to the water tank using the same process as used for the bead on the fuel tank. There are still a few things required such as the ladder, light and sand storage tanks for the water tank and the fuel tank must still be mounted to the cab floor. I'm leaving those till later. The following photo shows the tanks at this point.
Hindsight: Recall that I used material considerably thicker than suggested by Kenneth. The resulting tanks are very strong --- like a tank (armored vehicle). They are really heavy too. If I had it to do over I'd make the sides a few gauges thinner to ease the bending. It wouldn't hurt to make the top and bottom closer to Kenneth's recommendation either.
Update 9/23/05: Quick Connect fittings were installed on the output water lines. See More Improvements. End Update.