[jroark]

Hey guys. I'm not an expert so take this with a grain of salt but in my experience of late welding cast aluminum I found that spool gunning it works pretty good. I fixed a skag on a friend of mines boat a few weeks ago. Wasn't sure if the spool gun would work but we brushed the paint off, acetoned it, and the spool gun worked great.
After that little job I picked up a little fix on a old light fixture and it worked out fine. I got a picture of that.

Not sure I would use this method on something that would be under much stress but on something like these things give it a shot. I guess the spool gun doesn't put as much heat in the part as a tig weld would and maybe that helps it. Any experts feel free to chime in and correct me or agree if possible

[RamboBaby]

Did you do each joint with one shot or did you give it a shot, slick it of and shoot it again?
I've never welded on castings or done aluminum mig but, in my estimation, that came out really good.
I've seen so many aluminum mig welds break right down their centers that I've never even wanted to try it. It just seems to me like they're more brittle than tig. But with castings that are brittle anyway, that might be a good thing.

[jroark]

I just did all the welding first then smoothed the top side and the bottom. I left some weld on the sides. I dropped it on my table after it cooled just to check it out. I was skeptical about it working but I was pleasantly surprised.

[schaefer_don]

I've been struggling with TIG welding cast aluminum for a while, adding fuel injection bungs to an old-school Offy intake manifold. All the recommendations from Jody's videos (to keep your welds from looking like "Fido's butt") are a must: clean the part thoroughly; pre-heat; use aluminum prep cleaner; 50/50 Argon/Helium or pure Helium; etc. Here's another trick I discovered when I was about ready to give up on the entire project: Polish the cast aluminum to as bright a shine as you can. I used progressively finer Scotchbrite abrasive discs on my die grinder until I had nearly a mirror-like finish. Then, after cleaning and pre-heating, I struck up the TIG torch. The arc barely wandered and I was able to get a good puddle going. The TIG rod deposition was nearly as clean as welding steel. Give it a try the next time you're welding cast aluminum.