Mr. Lyons suggested that I clean off the inside with Scotch Bright. As I did, I noticed a lot of black dust coming off of the tube. It collected as a dusty shadow on the ground. I'm glad this stuff won't be running through my tractor.
|Scotch Bright getting dirtier|
|Junk from the tube interior|
Next I took the angle grinder to all the surfaces that I was going to weld (to take off the mill scale). Then I ground a chamfer into the flanges. This is a small angle that will allow fill material to flow between the surfaces that I will weld.
|Ground and ready for welding|
It turns out that professionals assemble gas tanks and other water tight things using TIG welding. TIG is a stick welding technology that gives extensive control over a weld. You apply heat and add material separately. This means that as you weld, you can backtrack and fill holes.
I decided to use TIG instead of MIG for this job. First I welded the large flange to the standoff tube. It went well except for a mild burn to my leg and a crater from my attempt to weld without any shielding gas.
|The first section of the weld. The tip of the TIG gun is visible shown.|
You can see that the chamfer leaves a gap between the flange and tube.
|This is what happens when the shielding gas isn't turned on.|
Fortunately you can weld back over the spot pretty easily.
I finished the flange and then welded the tube to the tank. I forgot to get a picture of that. I'll include that next week. I'm pretty happy with the product, the welds look good and are almost certainly air tight and very strong.
* Timesheet updated
* Open and Closed questions updated