[TheForge] Welding cast iron

[Bruce Freeman]

Okay, idea time:

I've long wondered (having no practical experience in the matter AT ALL) whether the problems in welding cast iron were due to the graphite (carbon).  Folks sometimes say that the stuff has absorbed oil or grease.  Well, castings CAN be porous, but it strikes me that if grease were the problem with welding cast iron, then it would be more of a problem in welding steel.  (You don't want a lot of junk on steel, but you don't need perfect cleanliness - the grease will burn off.)

But graphite would burn off less readily, and more would be exposed as you melted the mother metal.

So if graphite is the problem, how can you get rid of it?  

So I looked up graphite on the web and found that it's soluble in something * molten iron!    This suggests that a pure iron electrode might be a good candidate for welding cast iron.

This is all by guess and by golly.  I'd be interested if anyone has ever tried it.

Bruce
NJ

>>> gladish at cnw.com 12/4/2005 11:29:16 AM >>>
One tip that has helped me in the past is to use a file rather than a 
grinder to clean the mating edges. The explanation given to me is that 
the grinder smears the carbon that is in the cast iron (high percentage) 
and makes a dirty surface, though it's not apparent to the eye.<snip>
Andy G.\