DO NOT WELD on rim with tire mounted. 

Previous thread with links to what happens 

http://talk.newagtalk.com/forums/thread-view.asp?tid=507346

Take a few minutes to read it and watch the video links in that thread. The life you save may just be your own or someone you care about.

You need to understand what happens with Pyrolysis when the heat builds within the tire itself.

http://en.wikipedia.org/wiki/Pyrolysis

Here is another from Michelin just in case your still not getting the point.

https://www.youtube.com/watch?v=pNZ4siYGkag

 And another from Bridgestone 

https://www.youtube.com/watch?v=jBUVzgCHHuA

That being said you want a quality weld on the rim so maybe taking rim to a good welder dismounted might be worth it.

You sure don't want it looking like this one.

Photo courtesy of MCatSHF from this thread about an auction item.

talk.newagtalk.com/forums/thread-view.asp?tid=575657

I sure do miss MCatSHF's informative builds, pictures and humor. Wish he would reconsider participating here.

(weld.JPG)

weld.JPG (92KB - 68 downloads)