Help, I forgot how to weld aluminum

[Rex Schimmer]

Don,
One more comment regarding making tanks from .060 aluminum. I still think that using a tee dollie and radiusing the corners makes the best tanks from .060 and I need to add one more step if you do it this way. Once you have completed the weld on the outside you need to go back to the inside of the weld and do a back weld which really consist of just starting a puddle on the back side of the weld and moving it the length of the weld. Doing this will completely eliminate all of the weld "smegma" that you normally will see on the back side of the weld which is filler rod and excessive weld. By back welding you will eliminate this junk and greatly increase the strength and greatly reduce the potential leaks. I have made a number of gas tanks, water tanks and radiators using this method and have good success.

When I get home from vacation I will make a small tank and take some pics to post.

Rex

[donpearsall]

OK,
Here is the completed tank. Looks ugly but does not leak. I know it would be a lot better with non-corner welds like some have suggested, but I don't have equipment for that. Willie was the winner with his "turn up the gas" tip. I went by the book settings which said to run 10 CFM of Argon, but it turns out that it really needs a lot more. My gauge only goes up to 25 CFM and that is where the weld puddles were happy.

Thank you to everyone for their great tips. My next tank will be a lot better now.

Don

[Peter Jack]

Just one more tip Don. Whenever possible with an aluminum tank use saddles and a strap rather than a welded on bracket to mount the tank. If the tank is going to crack the welded on bracket is where it's going to happen.

Pete

[wobblywalrus]

Don, a suggestion from a guy at the shallow end of the talent pool.  In the days when I welded, I sometimes got my alloys and rods mixed up so I was actually welding with different materials than I thought I was using.  I had similar problems. 

[Rex Schimmer]

Don,
Looks like you had the amperage a little high and I'll bet you were using 3/32 rod. The increased gas flow cooled the weld and the high amps and big rod made the big welds, but if it doesn't leak it's PERFECT!!!!

Rex