I WORK IN AN AUTOMOTIVE MAINTENANCE SHOP, AND AM TASKED WITH WELDING A BROKEN PIECE OF CAST ALUMINUM STRUCTURE, SOME OF WHICH IS IN BLOCK FORM THAT NEEDS TO BE BEVELED, SO THERE'S SOME FILLING TO DO. NOBODY IN MY SHOP HAS HAD MUCH LUCK WITH CAST ALUM. BUT THIS IS A JOB WE WANT TO KEEP IN SHOP. I PICK UP WELL ON NEW PROCESSES THAT I'VE NEVER TRIED BEFORE, SO IF SOMEONE COULD GIVE ME A QUICK RUNDOWN ON HOW TO DO THIS, IS OXY-FUEL THE BESTWAY, OR ALUM MIG PERHAPS?
THANKS IN ADVANCE FOR ANYBODY'S EXPERT ADVICE!
-BUFFALO-
Lots of vairables in your question, alot of folks prefer GTAW A/C for repair of aluminum castings. Depending on the alloy type and geometry you may need to pay close attention to pre-post heat treatment requirements. Also cleaning and surface prep is critical. you will find many posts in both the Technical and Shop sections just do a search on "Aluminum"
Here is some good text on GTAW of aluminum... pay special attention to the Aluminum GTAW Squarewave section
http://www.machinist.org/army_welding/Ch7.htm#s4
The more you can tell us about the stuff your welding the more specific the responces will become.
Good Luck!
the last post is correct in saying that GTAW (TIG) is the prefered way to weld castings because it is slower. how you weld it, and with what also depends on what KIND of aluminum you have...whether it's heat treated, alloyed, or high tensile strength all matters when talking about a thick casting. it sounds like you're gonna be welding an engine block or transmission housing...is that correct? if so, you want to get it right the first time for sure so you don't leave your customer hanging somewhere in the middle of nowhere! hehehe if you can't find out what kind of aluminum it is, you can take it to a certified weld inspector's (CWI) shop and they can do some testing on it to figure out what it is.
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