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I Forge Iron

slightly off topic: TIG/Stick Welding Wrought

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Figured you guys might be able to answer this question.

Which works best for welding early steel or Wrought Iron? Also which alloy filler or welding rod works best?

I am in the middle of moving a coach for the Railroad Museum in Willimantic, Ct. We may have to cut off a brake hanger from the car so it can sit low enough on the trailer, to clear wires and such. Unfortunately the hanger is held on with long square head bolts that are socketed into the wood beams under the floor, so if they start to spin or jam, the floor would have to be removed to access them. Since the plan is to return the car to service, the weld needs to be near the strength of the original material. The bracket is about 1/4-5/16 thick by 3 inches wide and when made was bent 90 degrees the hard way (square interior corner with 3" radius on the outer corner), or at least it doesn't look cut or machined from plate. The coach was built in 1902, by Osgood-Bradley car works in Worcester, Ma. After looking at the part, I don't see any grain pattern in the bend area, but it could have been smoothed after they bent the part, so I am not sure if it was made out of early steel or wrought iron.


Rich Cizik
MoW Foreman
Blacksmith Shop Co-Head
Ct Eastern RR Museum
Willimantic, Ct 06226
Connecticut Eastern Railroad Museum

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A less destructive test for wrought iron:

From "Formulas for Profit", Bennett, copyright 1939, 4th printing

"To identify iron from steel"
"Mix 5 drops nitric acid with 10 drops H2O", (remember acid into water *NEVER* water into acid),"File a clean spot and place a drop on it.

If it is steel it will turn black immediatly. If it is wrought iron or malleable iron it will stay bright for a considerable length of time."

Use at your own risk!

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Summarizing to see if I understand the parameters:

1) L shaped bracket 1/4" to 5/16" thick by 3 inches wide.
2) if bracket is cut it will have to be removed and repaired or replaced
3) unknown material
4) critical part that needs to be at maximum/original strength
5) part is bolted to wood surface and can not be welded in place because of fire hazard.

My suggestion; make a replacement part preferably stronger than the original using modern and known materials. If you provide a drawing or photograph of the part we could better provide suggestions on different ways to make the part. If it is simply an L shaped bracket, you may be able to reproduce the bracket simply drilling and modifying a piece of suitably sized angle iron.

Best wishes,
Dave E. :)

Edited by UnicornForge
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Total removal of the part is not a practical option, since the oak tongue & groove floor would also need to be removed to access the top of the bolt. Welding could be carefully done under the car, after wetting the surrounding wood, installing spark shields (tin suspended from the underside of the floor) and heat absorbent gel, as the cut could be made about 2-3 inches off the wood

Here is what the piece looks like (inside the blue line), I figure it can be cut in the area of the twist, either above or below with a porta-band, but welding it back together was the head scratcher. I was leaning towards TIG, since it sparks less and the heat can be controlled better.

What are your opinions?

Rich C.

Edited by mod07
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Dave, Total removal of the part is not a practical option, since the oak tongue & groove floor would also need to be removed to access the top of the bolt. Welding could be carefully done under the car, after wetting the surrounding wood, ....... What are your opinions? Rich C.

If I were you I would first talk to whoever is overseeing the car's renovation and find out if they plan on removing the wood floor as part of the renovation. Since that is a critical part of the brake I would advise against taking any shortcuts. If they are going to be removing the floor, ask if the carpenter could remove a couple of boards prior to the move so that you can access any parts that need to be unbolted.

If they are removing the floor later, you might consider cutting the part and making a new one for installation prior to the floor re-installation.
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Sure, you can tig weld it with a steel filler rod. You must get the base metal very, very clean though, or you will get bubbles in the weld. Normaly, I just use stainless tig wire, and don't worry about it, but the paint might not stick or something. I supose you could weld it with stainless, then prime with selfetching primer, before painting.

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what size bolts are holding the bracket, do they extend past the nuts, or are they threaded into the plate?

If they extend past the plate, and sufficient size you can square the end to hold with a wrench to keep from spinning, or slot and hold with a screwdriver. Use lots of Kroil first. BTW Kroil is the best penetrating oil I have ever used, amazing stuff.

You can also TIG a setscrew to the end and hold with an Allen wrench.

Cut nuts off by splitting instead of unscrewing. Clean threads, and replace with new ones.

TIG can be used, but it will take multiple passes, and strength of weld may be an issue.

MIG CO2 gives better penetration, but more splatter than a 75%-25% mix.

Stick weld with a 7018 rod. Very little splatter, slag virtually falls off on its own, and very strong.

If you have a chunk of copper laying around-I have also used brass and aluminum-you can use it for a backing strip to keep you from blowing through. You want to put some heat to this , so you do not get any cold shut.

More pictures (closer) , or a drawing would help.

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