[TheForge] Welding cast iron

[Ralph Sproul]

Hi Bob, I usually preheat to 450.  I then do stitch welds about 3/4 - 1 1/4"
long and peen them to stress relieve them as I go along. The other thing is
my second stitch is opposite of the first one (if you can get to the
opposite side of the repair.  This tends to keep the stress even especially
when getting it together rugged enough to keep at it.  The other thing is if
I'm doing lots of welds I check the weldment with a tempil marker to keep it
under 750-800 degrees.  With mulitple passes - this heat can build up rather
quickly if the part is small........so I slow down - work on something else
and keep welding not allowing it to really go below 400 again.  When I'm
done, I wrap the larger parts in a piece of insulation and let it cool
slower than by leaving it alone in still air.

I find V'ing out the weld 1/3 from each side - and leaving a good reference
in the center for the part to go back together exactly where it cracked or
broke apart. (of coure jagged or shard sections need removed, and ends of
cracks if you have any should be drilled.....to keep them from traveling
further.

I hope you have some of the rod already - or hold on to your hat when you go
to buy any.......nickel rod is expensive.  There are about a half dozen
different rods for cast repair.  There is 99% nickel, 50% nickel, 2% nickel,
no nickle, and then the repair rods for oily/dirty cast, etc.   If you have
a couple types try them to see which one works best.  Some of the rods (just
to warn you - are not machineable) so they must be ground for clean up or
finish.

I also find on smaller parts that clamping them to a plate and preheating
the plate and part keeps the weldment more consistent temperature wise.

Good luck

Ralph

-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net]On Behalf Of Bob Ehrenberger
Sent: Sunday, December 04, 2005 11:56 AM
To: theforge
Subject: [TheForge] Welding cast iron


I have a need to weld a cast iron part.  What is the appropriat preheat/post
heat temp.

I was thinking around 600 deg. Am I close?

The last time (about 10 years ago) I just put the part on top of the wood
burning stove. Now I have an oven in the shop so I can use a little more
control.

Robert Ehrenberger
Shelbyville, Mo.
eforge at centurytel.net

_______________________________________________
Manage membership or unsubscribe at:
http://mailman.qth.net/mailman/listinfo/theforge
theforge mail list group photo site is
http://www.photoaccess.com
Login:  blacksmithblacksmith at hotmail.com
password:  anvil
___________