1450 Diamond Station Road, Ephrata PA 17522
After reading the article in the Readers Write column of August
GEM on welding cast iron, it prompted me to share a procedure that
works well for me. We have a metal working and machine shop and
have yet to have a piece come back to us.
I agree with Mr. Larson on grinding the crack out far enough,
because the more area you have for the weld to knit to, the better.
The next step is to tack weld the pieces together properly. No
preheating is required.
We use 1/8 nickel welding rods and run
them at 110 or 120 amps AC. Have a small ball peen hammer handy.
Now lay down about a ?’ long weld bead, weaving back and forth
to get a good hold on both pieces. Immediately peen the weld in
while it is still red hot. The idea of peening the weld in is to
relieve the casting of any stress caused by the weld shrinking and
cooling thus replacing the preheating process. When you have it
peened in well, repeat the welding and peening cycles till the
entire weld is complete. If the crack is quite deep or wide to fill
up, make more than one pass. Take your time in doing this; you will
not be disappointed with your efforts. Make sure you get enough
weld on it. Any excess can be ground off.
We feel this is a much simpler way to weld cast iron than trying
to preheat it in a forge, which can be quite a major undertaking
with a large casting. Operating a forge properly takes quite a bit
of practice and learning.