[TheForge] Welding cast wood stove baffle

[Michael Boettcher]

At 08:42 PM 4/8/2002 -0400, you wrote:
><excellent advice snipped>
>Ralph
The part is cast iron.  During stop drilling, the chips (powder actually) 
was black.  I'm used to seeing a dark grey, but not BLACK. The first 1/64 
to 1/32" was really black as well.  We ended up brazing it.

After doing a bit of research, and talking with people, I found the Lincon 
"The Procedure Handbook of Arc Welding."  In it they said:

Castings with High-Graphite Content:  Castings having a great amount of 
large, free graphite flakes are difficult to weld, since the weld metal 
does not fuse to graphite.  Instead, it tends to ball-up and resists 
working into the melted surface of the casting.  This behavior is most 
common on castings that have been heated repeatedly, such as old furnace 
grates or exhaust manifolds.  The ESt electrodes for cast iron have a 
coating designed to flux out some of this flaky graphite, thereby improving 
fusion.

The balling up of the weld material was really evident when I tried to weld 
it.  So...  I guess the answer is to get a cast iron rod, preheat the 
entire thing up to almost dull red, and weld away.  Hmmm... with the way 
the welding went, I think it needs to be in a bed of sand to support the 
molten burn-thru.

Thanks everyone for your advice.

Michael
Madison, WI