Hi SWNORRIS, Yes I weld these a fair amount of the time. I own a welding shop where I do tool welding, repair welding and custom fabrication. I do weld many of these aluminum castings along with boats, skegs, etc.. When I weld any casting or old aluminum its a two step welding project, maybe three step. I will clean with solvents, sandblast part and heat in my oven up to around 400- 500 degrees. I have welded many old aluminum & cast iron Harley Davidson castings which weld fairly well, for a local Harley restorer in my area.

During welding I'll see the black junk develop on top and wire brush it off and sometimes there's the need to even grind down the weld area, I'll also change tungsten often for it gets contaminated easily during the first weld attempt. In most situations I am able to cover area good during the second welding attempt.

I have welded many boats also and they are a pain in the but just like a casting is.

What I am wondering is if there is a solution I could make up and boil the casting in prior to welding to bring out any and all oil or etc.... Just this week I did 5 different aluminum castings and all of them like the last 50 I did during the past year needed the same two step welding process. My process is 1st cleaning , 2nd sandblasting, 3rd pre-heating, 4th welding, 5th deburring some of the weld out, and 6th welding again. I even had 2 last week that I had to grind twice and weld 3 times on to achieve a satisfactory weld area.

I have tried 2%, pure, zirconiated or ceriated can't remember which one I have tungsten box marked at shop. I ;ve tried 3/32, 1/8" diameter I have also tried varying my heat input.

Bottom line, I always say welding an aluminum casting is a 2 or 3 step welding process, so if anybody has some tricks they do I'd love to hear them. By the way what temp. does aluminum melt at.