It's been a while since I've made a log entry. Free time has been elusive. Progress on the tank has been steady. Most of my limited time has been spent leak testing the tank; filling the tank with water, marking seeping areas, and re-welding. Most leaks were at the corners, where sides and bottom meet. The most effective way I've found to eliminate a leak is to grind down the weld and re-weld.
The tank has been full of water and leak free for three days, so it's time to install the top and fittings.
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The top is welded to the tank body. After cooling, I pressure tested the tank. A 3/8" hole is drilled in the top at the approximate location of the closet flange fitting and a piece of plastic tube is inserted. The tank is pressurized with air to 4 psi, and a soap and water solution is sprayed along the seams. No leaks were found.
With the tank pressure tested and leak free, the fittings are welded to the tank. Fittings used are 1.5" slip fitting for the vent, 3" female fitting for the closet flange, and 3" slip fitting for the dump drain.
The tank is almost complete. I plan to add a deck plate to the top of the tank for cleanout access, and several fittings for installation of a hands-free rinse system. For now though, I'm finished with the tank.
That's all for today.