16 Mar
2012
16 Mar
'12
12:28 a.m.
On 15 Mar 2012 at 19:42, jthecman at netscape.net wrote:
Hello
I have two problems that I need help with, one is an IBM Card
Interpeter model 552 that has 3 broken legs. I think it's cast iron
and one welder told me he could weld the legs back on the unit. Does
anyone if these can be repaired or should we build a box with wheels
to set it in for museum display? The second problem is a set of Apple
MAC 20th Anv pens that have, the pen bodies have turned very soft and
sticky and help on stopping this so that these too can be part of a
display?
Cast iron's a b*tch to repair because it's brittle as glass. That's
why, for instance a pipe cutter for cast iron plumbing simply applies
point-pressure along a line and the pipe just breaks off. That's
also why you can demolish a cast-iron bathtub using nothing more than
a sledge hammer.
I've heard of repairing cast-iron machinery by brazing, rather than
welding (lower temperature), with the cast-iron workpiece pre-heated
to minimize thermal stresses. You should probably stud the parts
together to add some strength and just braze right over the studding.
I've also heard of repairing a preheated cast-iron workpiece by using
stainless filler wire in a MIG welder. There are (expensive) cast-
iron welding rods for use in a normal arc welder, butt he results are
often ugly and accompanied by workpiece cracking--and the joint is
brittle and hard as glass (because of the high carbon content of cast
iron).
Whatever you do, don't have the work done by someone who's never
worked with cast iron. It requires a careful touch; knowing what one
is doing is vital.
Good luck!
--Chuck