[TheForge] welding rusting metal

[theforge@mailman.qth.net]

Can someone recommend a good stick to use for welding rusting metal.  The 1/2 
wall 6" by 6" steel tube for the upright of the power hammer I am going to 
build has been sitting outside for a few months and now it is rusted all over.  
I am going to fill the in inside with concrete to add stability but the outside 
has to have the hammer support welded to it. Clean it?  Polish it? weld right 
through the rust? suggestions?

Dan