One way to repair cast iron.

   / One way to repair cast iron. #1  

jwmorris

Veteran Member
Joined
Oct 3, 2007
Messages
1,033
This is a method I use fairly often for cast iron repairs, using a TIG welder and silicon bronze filler rod. Broken part is sand blasted, with most attention on fracture area.

56066AC6-F425-4C44-8137-C6A3EDE36829.jpeg


Set up parts so fracture is aligned just "sitting there", a clamp and shims can help.

BAB67344-E06C-432E-A233-99C17D41BC3D.jpeg


Grind away material to gain surface area for the silicon bronze to adhere to but leave enough for the parts to be perfectly aligned at the cleave.

615B3F42-D710-44D7-925A-B4B95C0CC967.jpeg
66E23F6A-F428-4AB4-8BCD-4A0BECC86257.jpeg


Tac either end, top and bottom, make a root pass and come back with a few more to fully fill the joint.

5F39E622-6447-4465-8AEA-475EAFA841E8.jpeg
207C1D1D-6BA7-4819-89FB-33F1DDD945D7.jpeg


Sand it, if you want it to look pretty.

ACF00C3A-4B88-4249-B011-731DB026B568.jpeg
 
   / One way to repair cast iron.
  • Thread Starter
#3  
It’s the eccentric cam that operates the clamp on an 8ft brake. This is it installed.

F06C47CB-3035-4EA8-B093-67D56E94AC75.jpeg


It is a fairly decent repair method due to ease (no pre/post heat) and the other side has been knocked off twice and it failed at a different spot than where the first repair was, up into a thicker section of the arm.

3613C0E9-CC14-49C4-B000-D304A3470299.jpeg
 
Last edited:
   / One way to repair cast iron. #4  
structurally, wonder how the weld would compare in strength to old school brazing. yours probably stronger w/the penetration. looks like a carefully done repair, regards
 
   / One way to repair cast iron. #5  
On small parts like yours pre-heat is often not needed. For large parts I will build a temporary "oven" out of fire brick and/or ceramic wool made for kilns. A few years back I needed to repair a large drill press table and pre-heating while it was on the weld bench and then TIG brazing did not prevent cracking upon cooling. So I laid down fire brick on the weld bench, then stacked more bricks on the ones already down to make walls. The walls were a close fit to the drill press table. After heating to the table to almost a dull red with a weed burner I TIG brazed up the cracks. I used ceramic wool to cover to cover the table except where I was brazing. After brazing I covered the whole thing and let it cool overnight. No cracks. I have repaired other stuff the same way. Sometimes with a torch and brazing rod but mostly using TIG and silicon bronze rod because itworks so well.
Eric
 
   / One way to repair cast iron. #7  
Nice repair. You can use SIB with gas too but Tig will be slightly stronger @50K. LFB brazed has a higher tensile @65K. Both are great ways to fix this but if you plan to use oxy-fuel I like the Nickel Silver rods. 95K tensile and is all position. It's all good actually. I enjoy messing with Cast Iron repair.
 
   / One way to repair cast iron. #8  
Nice repair. You can use SIB with gas too but Tig will be slightly stronger @50K. LFB brazed has a higher tensile @65K. Both are great ways to fix this but if you plan to use oxy-fuel I like the Nickel Silver rods. 95K tensile and is all position. It's all good actually. I enjoy messing with Cast Iron repair.

Yes, nice repair work. I enjoy torch work - and do quite a bit with the nickle/bronze and sometimes use nickel/silver. I would love to hear some more about Tig brazing work - especially with with nickel alloys on stainless, hastelloy, Ti & others.

I was all set up to look into that myself, as a retirement project - but a pacemaker made me change those plans. I just recently sold off all that tooling and am back to the torch.

Tig is clearly a cleaner source than the torch- though I'm constantly surprised at what a torch can do.

rScotty
 
   / One way to repair cast iron.
  • Thread Starter
#9  
Thanks for the update. That brake looks like it's been in service for a while.

It was, went down hill in storage at our farm though and broken (again). I am in the process of cleaning it up now. Becoming functional again is the first step, after getting it back home.

I also had to straighten the arms for the counter weights but that’s a different forum.

There are a number of ways to fix broken cast iron parts, what one I choose depends on a number of factors but the method above is an easy one. Certainly not the most difficult and I try to not complicate things, if I don’t have to.

A TIG gives me more control than a torch without all the extra flame.
 
Last edited:
 
Top