A friend just brazed a cast-iron steady rest for me, and it appears to
work just fine. Brazing can definitely work. But to do it right is a
lot of work. Preheat for a while, and after brazing, cool it slowly.
I've read that cast iron can be welded but it's quite difficult. I
would consider instead making or buying a fitting that would connect
the pipe to the drain---doesn't it have a thread already?---- then plug
the overflow hole with furnace cement or something similar.
Regards -- Terry
You can arcweld cast iron with nickel rod, but chances are it will crack as
it cools. How are you planning to heat a whole bathtub full of lead? Heat
the tub, do the welding, and then cool it slowly.
I think it would be easier (and safer) to build a tub out of steel. The
last thing you want is a tub full of molten lead that suddenly gets a crack.
Depends on the cast iron. Some is fairly easy to weld, some is
Why don't you go in with Sierevello and me on some HTS-521 brazing
rod? That would work, and it would withstand the temperature of
I have stick welded cast iron (DC reverse I think it was) using an
oxy/acytlene torch with heating tip to preheat the part. You use
temperature crayons one on the low side of your heat range and one on
your high side. I used Eutectic nickel rods specific for cast iron and
Eutectec had a handy book at the time how to do it. I prepped the part
(a big ol' cracked power hacksaw arm) by veeing the joint both sides and
I very carefully made sure I had my mounting holes alligned properly. I
1st tack welded it to keep it together, then layed in my weld in layers.
Between passes I peened the weld to stress relieve it. I had to be very
careful not to warp it as it was a heavy section about an inch thick.
When done I let it air cool to room temperature.
What had happened was I was cutting 6 inch cored out D2 in sections of
various thickness for cold roll forming mills tooling sets. (I ran my
own deparment making up 60 to 100 piece sets (not one the same) all
freehand in an old clunker LeBlond lathe. When done they were hardened
and double tempered at 65 Rc.) This was a power hacksaw using 2 inch
wide Starret hacksaw blades. This big old clunker saw was always run in
low speed of a 4 speed gearbox. I tried to speed up the process and the
added torque sheared the hacksaw arm. I was working night shift. My
heart was in my mouth, let me tell you! At one point in my life I used
to do maintenance welding. In another department in our shop I knew the
maintenance guy used Eutectic rods so I borrowed his. By quitting time
that night I had repaired it and reassembled the saw. I never got
chewed out for it. To cost that repair job out would have cost them a
few hundred dollars.
Another time I did CNC production work in a specialty valve shop of
automatic control valves. I was told by the engineering department
there that you do not weld cast iron as a repair if the castings are
cracked in high pressure steam applications. I know we have the
engineering and scientific community also frequent here and maybe they
can add more guts to this conversation of live steam application do's
More than you wanted to know I am sure...
I would think any porcelin in the mix might make welding cast iron
Group: rec.crafts.metalworking Date: Sat, May 13, 2006, 11:43pm (EDT-3)
I have a bath tub that I want to use to melt lead in [ for a boat keel]
can a black iron pipe be welded to the drain hole? I would also like
cover the overflow hole.
Find a steel tank. I sure wouldn't want to be standing anywhere near a
cast iron tub full of molten lead when it cracks due to uneven heating.
I'd also be surprised if the porcelain didn't spall off like popcorn.
I've seen several keel pouring setups in boatyards here in Maine and all
used steel vessels. The largest was heated with 3 or 4 domestic oil
burners aimed into an enclosure under the tank.