One way to repair cast iron.

[jwmorris]

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.

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

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.

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

Sand it, if you want it to look pretty.

 

[California]

Looks good! What is that part?

 

[jwmorris]

It’s the eccentric cam that operates the clamp on an 8ft brake. This is it installed.

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.

 

[big bubba]

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

 

[etpm]

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

 

[California]

It’s the eccentric cam that operates the clamp on an 8ft brake. This is it installed.

Thanks for the update. That brake looks like it's been in service for a while.

 

[yomax4]

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.

 

[rScotty]

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

 

[jwmorris]

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.

 

[SailingMaster]

Looks sharp!