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Repairing older metal parts
https://rypn.org/forums/viewtopic.php?f=1&t=49122		 Page 1 of 1
Author:  EEaton [ Wed Feb 11, 2026 3:23 pm ]
Post subject:  Repairing older metal parts
I could use some advice from someone with experience welding old (1920-1925) cast or forged steel. These parts spark test like steel and are physically malleable. I don't believe it is malleable cast iron based on the spark test. They take hardened steel bushings that have loosened and spun requiring the holes to be filled somewhat and re bored. The faces are worn and need some build up. They have been welded on the faces at least once probably 70+ years ago. Both the old weld and the base metal "fizz" when melted with a TIG torch. Preheating to 400+ does not change the results. TIG - 100% argon with ER70S-6 ends up porous. Stainless 309L works but I suspect it will be harder to machine. These parts were obviously welded before. We could TIG braze them with silicon bronze but I was hoping for more wear resistance and I'm guessing the bushings would be retained better in a steel bore. For a sense of scale the ring shaped end has 2" OD. One picture shows old weld buildup. The other shows partially ground back ER70S-6 bead that has porosity. The video shows how the base metal with no filler bubbles and becomes porous when melted with TIG torch.
Image
Image
https://youtu.be/mCZjreIRjIY
Sorry- I'm not sure why the img links above don't work. Here are the same links using the URL method.
https://drive.google.com/file/d/1Te74mCim6wCf1UIye4XHrWtWZPG4aQWw/view?usp=sharing
https://drive.google.com/file/d/1ZjCLOw9Vr2UwslbTnaHOY4C0K_6uLie2/view?usp=sharing
Author:  David Johnston [ Thu Feb 12, 2026 2:14 am ]
Post subject:  Re: Repairing older metal parts
The material could be wrought iron. Ductile like steel, but not weldable. It is normally formed and fused together using blacksmithing techniques.
Author:  Dick_Morris [ Thu Feb 12, 2026 6:13 am ]
Post subject:  Re: Repairing older metal parts
Can you bore the hole just enough to clean it up but dialed in on the current hole, then make an oversized bushing with a new hole off center in the bushing but located in the correct place to give the proper spacing on the finished part? That's what we had to do on the fulcrum for the equalizer for the lead truck. If you look closely at the photo of the rebuilt part you can see the edge of the bushing and that the hole is well below center. I think some spring hangers got the same treatment.

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Author:  EEaton [ Thu Feb 12, 2026 11:42 am ]
Post subject:  Re: Repairing older metal parts
Dick_Morris wrote:
Can you bore the hole just enough to clean it up but dialed in on the current hole, then make an oversized bushing with a new hole off center in the bushing but located in the correct place to give the proper spacing on the finished part? That's what we had to do on the fulcrum for the equalizer for the lead truck. If you look closely at the photo of the rebuilt part you can see the edge of the bushing and that the hole is well below center. I think some spring hangers got the same treatment.



I was thinking this might be less intrusive and the amount of work vs using off the shelf bushings might balance out. We don't have a very good setup for heat treating them. I still need to find a way to resolve the wear on the faces. Someone welded these in the past.
Author:  EEaton [ Thu Feb 12, 2026 11:57 am ]
Post subject:  Re: Repairing older metal parts
David Johnston wrote:
The material could be wrought iron. Ductile like steel, but not weldable. It is normally formed and fused together using blacksmithing techniques.


Hi Dave, I was hoping you would chime in. These parts look more uniformly formed than other obviously blacksmithed parts. They would have been using full shape dies like forging. Not arguing they didn't, just was thinking steel would have been used. I didn't do the spark test. I'll go back and take a look at what would be expected for wrought iron.

I realize that wrought iron arc welds are not structural. I learned this a number of years ago after grafting a end onto a vertical tie bolt because Donald C really wanted to use the original material. I did a bend test on one repair that was full cross section welded with MIG. It snapped easily at the boundary between the weld and base metal without bending the base metal. Not something you want for a structural part.

How would you deal with the worn faces? Someone has obviously welded them up in the past.

Thanks again
Author:  EEaton [ Thu Feb 12, 2026 10:11 pm ]
Post subject:  Re: Repairing older metal parts
We did another spark test and compared it to some modern steel from a piece of angle iron - possibly A-36. They look similar to the base metal on the parts. Also there is some rust pitting but nowhere does it look like wrought iron's "wood" grain. I don't think it could be malleable cast iron either based on spark test.

Several of the parts have oversized and oblong holes that don't seem candidates for boring to fit an oversize bushing.
Author:  CJKlossner [ Thu Feb 12, 2026 11:27 pm ]
Post subject:  Re: Repairing older metal parts
The old repair was likely done with an acetylene torch. Some of those alloys do not respond well to the higher heat of tig. All of the old weld metal will have to be removed in order to use an er70 type filler.
Author:  EEaton [ Fri Feb 13, 2026 11:49 am ]
Post subject:  Re: Repairing older metal parts
RE gas welding- I had wondered about how it might work. The beads from previous repairs have fairly steep sides which don't seem characteristic of gas welds. In the rather bad video I posted the area fused was ground back a bunch. I can't claim it was through the original repair bead but it would have been close. The one face I did with 309L actually machined reasonably well and "only" had a bit of porosity in one section. If you look close at the old repair there is some small bubbles too. They might have used a nickel based rod.

No one has commented on the use of silicon bronze instead of steel or stainless filler. I realize the wear surfaces would be more vulnerable but given the service it will see it seems like a good tradeoff. I'm mostly concerned about how it would hold a bushing if we used bronze to buildup the part's ID. We also suspect these did not originally have bushings and are concerned that if we over bore the existing bushing holes the structure would be compromised.
Thanks for any advice/feedback.
Author:  CJKlossner [ Fri Feb 13, 2026 10:14 pm ]
Post subject:  Re: Repairing older metal parts
For tig to work the old filler will have to be removed past the the layer where the two have mixed. Since it has no flux to carry impurity's away it just makes bubbles. Being a thin wall part build up is probably the best repair.

Stainless will work if the part is cast because it will not draw carbon out of the iron and become brittle. It does work better with some pre and post heat. If it is a wear part the silicon bronze or aluminum bronze will likely wear better than stainless. Applying bronze with a torch would wear well also.
Author:  EEaton [ Mon Feb 16, 2026 10:04 pm ]
Post subject:  Re: Repairing older metal parts
CJKlossner wrote:
For tig to work the old filler will have to be removed past the the layer where the two have mixed. Since it has no flux to carry impurity's away it just makes bubbles. Being a thin wall part build up is probably the best repair.

Stainless will work if the part is cast because it will not draw carbon out of the iron and become brittle. It does work better with some pre and post heat. If it is a wear part the silicon bronze or aluminum bronze will likely wear better than stainless. Applying bronze with a torch would wear well also.


Thanks Chris,
I appreciate the feedback.

I'm not looking forward to building up the IDs but I think you are right. There are too many that would require a lot of metal removal to get them round again.

We bought a bunch of silicon bronze missing its original packaging from a local supply house for less than 10% of its list price. I've used it on several parts - you might say it is my hammer when it comes to brazing. Local supply houses don't stock the aluminum bronze which I understand is more resistant to wear and also tig-able. I like the tig because of the control you have over where it goes and how thick you lay it down. ( know a good hand can get reasonable results with a gas torch).

My understanding is that two bronze parts rubbing on each other is not ideal. These parts attach to castings which appear to be cast iron. I was thinking I'd repair the castings with Si bronze and do the corresponding faces on the parts show in this thread with steel/stainless for that reason.

Removing all the old repair down to the bottom of its penetration would not leave a lot. If I removed the weld bead itself do you think that might be enough if I used stainless on these parts? (if we wanted to have steel wearing against bronze)

Thanks again
Ernie
Author:  CJKlossner [ Mon Feb 16, 2026 11:40 pm ]
Post subject:  Re: Repairing older metal parts
Yes bronze on bronze does not make for a good wearing surface. Cast iron is really the only reliable metal to wear on itself. We are doing some gears in a similar manner. The small gear is getting 309 stainless and the large gear silicon bronze. The only difference being it is applied with mig.

It is really hard to say not knowing what the original filler was. I have found with contaminated aluminum castings the first pass is usually dirty. Grinding it off and the next will be good.

This is an axle thrust collar I did with a torch. It will be machined and wear against a cast wheel hub.

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Author:  EEaton [ Tue Feb 17, 2026 12:49 am ]
Post subject:  Re: Repairing older metal parts
CJKlossner wrote:
Yes bronze on bronze does not make for a good wearing surface. Cast iron is really the only reliable metal to wear on itself. We are doing some gears in a similar manner. The small gear is getting 309 stainless and the large gear silicon bronze. The only difference being it is applied with mig.

It is really hard to say not knowing what the original filler was. I have found with contaminated aluminum castings the first pass is usually dirty. Grinding it off and the next will be good.

This is an axle thrust collar I did with a torch. It will be machined and wear against a cast wheel hub.


Thanks, I'm going to take a closer look at how parts interact with others tomorrow. Nice job on the brazing. Our mig machine is a toy (145amp) so I went with tig. I put down 10+ lbs on some blacksmithed truss anchors that had rusted badly where they interfaced with a wood sill beam. That was my first TIG brazing and I was surprised how nice it worked.
I'm tempted to try to TIG 309 the faces and TIG Si Bronze the bore buildup. I find it a bit more difficult to shield the bore work with the required tungsten stick-out. I think the bronze would go better. You should have a private message with my phone number should you be willing to take a call tomorrow. Many thanks, Ernie
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