Cast aluminum filler?

[swyman]

I have a piece of cast aluminum to weld. Can I use 5356??? If not, which type??
Thanks, Shane

[terry welds]

cast aluminum

the last time i welded cast alum. it was a tranmisson. and i used er4043 and it seemed to work ok. it is still holding today

[JonnyTIG]

You can use either 5356 or 4043. The 4043 may match the casting color better than the 5356, and is also heat treatable if that is a concern. 5356 will produce a stronger weld, however the base metal will most likely be lesser in strength, so there probably wont be any advantage to welding with the 5356.

[yorkiepap]

Casting prep....

Hey swyman,
I do agree with JonnyTIG regarding filler. 4043 is a bit more forgiving, but 5356 is stronger. I use 5356 95% of the time with the MIG process and 4043 on occasion. Take into consideration, if the casting is over 1/4" thick, much better results will be had by preheating the casting to 250-300 deg.. And the most important factor for a sound weld is the cleanliness of the aluminum. Aluminum is very finicky if there is any kind of contamination on the metal. Wire brushing with a SS brush and acetone vigorously will generally get the metal clean for a good weld joint. Hope that helps a bit.....Denny

[HMW]

I use 4043 alot [tig] on cast aluminum. Seems to work fine. i have repaired some of the coolest antique toy tractors with this rod, grant it strength is not a big issue, but it seems to weld good. Also repaired several transmission covers/cases also and seems to work good