[Kevin in NJ]

Get a copper, bronze will work but the tin comes to the surface, the correct diameter. Does not have to be perfect. You might need to grind it some to open up the hole so you can weld along the length. Truth is if it is thin enough you will easily burn through and fill up the void. I have used brass and bronze in the past to back welds and did not like it, copper is best!!

If you are using a MIG welder also get some TIG rods of the same metal type to help the fill rate. Run the arc on the tig rod for a better fill.

You do not need a perfect fill in, just enough to give support to the bushing you will put in place. Some voids and such are not a problem and you are likely to get them. The goal is to support the bushing properly. After you get the area nicely welded up drill to the proper diameter and make it look pretty. Press the bushing in place and you should be good to go.

I had a really bad axle housing and did a practice try after reading about this a few years ago. Pretty easy to do and a great way to save a housing.