welding cast aluminum

[49chopper]

For starters let me say I know just enough about welding to be dangerous.
I won't be doing the welding on this project I just want to be well informed so I'm sure to get a good job done.
I have a 1949 harley panhead and both motor mounts in the front have broken off. For background the are tabs sticking out on the front of the crankcase.
Any suggestions/ help will be greatly appreciated. I really want to get my baby back on the road, but safely of course. I"m pulling the motor this afternoon and think I have a line on someone capable of doing the welding.

[Pangea]

Probably the most important two things you should consider is making sure that you have a competent welder to do the job and that the cases don't warp from the heat.

The welder will clean the parts like he is about to do brain surgery on one of his own kids. He will line up the broken edges, tack in place, then grind bevels to accommodate a fully penetrating weld bead. The finished welds should be light gray with no pinholes or black spots. The welds can be worked down and polished but they won't look the same as the parent material. I'd leave them if they looked good like proud battle scars..

[EricHSmith]

I just did a similar job and used HyloCool. As well as the suggestions from Pangea such as cleaning the fire out of it and getting a good bevel for penetration. I also used the same process last year on my 1948 Indian to repair a fin on the jug. I used .035 wire for filler on that one so I could lay a smaller bead.

[SidecarFlip]

At least it's good aluminum unlike the PDC pot metal used today.