[AT] Spam> welding aluminum

[John Hall]

Not tractor related but it's 60 years old. Need some advice welding cast 
alum. Appears to be good quality casting--no sign of porosity. The guy 
trying to weld the part for me slightly preheated the part and then started 
Tig welding. About 5 seconds after he would stop, the weld would crack. 
After he welded and let the part cool for 2 hours I could pull it apart by 
hand. Besides the hairline cracks the weld looked great--no signs of 
contamination or air pockets. Oh yeah the parts had been degreased and then 
bead blasted.

Any suggestions?

John Hall