# Welding unknown stuff



## cathead (Oct 29, 2020)

I found several of these modified clamps at the scrap yard so took them home as I could see some utility in them. 
The malleable steel was apparently welded to a piece of what looks like stainless but without any way to mount them
needed a little more modification.  I bored a 1/2 inch hole in a piece of mild steel and arc welded it on to the "stainless"
part with some 1/8 inch 6010 rod.  It looks like it will be fine as a work holder on the drill press possibly or maybe would
have some wood working applications as well.  It would work on the mill for a hold down for that matter.  It was my morning
project while waiting for some paint to dry on another project.  
	

		
			
		

		
	



These were red with rust and stuck so had to work them over.  I'm sure they came from some welding shop as they were with
a bunch of other welding related stuff.  Anyway they're saved from doom.  I'm not sure what I will do with the second one on the left.


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## rwm (Oct 29, 2020)

I would have though those were cast iron but maybe forged steel? CI would not typically weld very well. How are C clamps typically made?
Robert


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## MrWhoopee (Oct 29, 2020)

My guess is the clamps are cast steel.


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## cathead (Oct 29, 2020)

I know they are not cast iron because if one puts enough force on them, they will bend(from past experience).  The little plate
welded to the bottom is what I suspect to be stainless steel of some sort.  The smaller piece with the hole added to the
bottom is just mild steel.  I used 6010 welding rod since it has good penetration.  I have no idea if this is a common
practice to weld stainless to mild steel but it seems to be holding well enough.  But then I really don't know what that
bottom plate is made of.....


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## ericc (Oct 29, 2020)

I had a C-clamp which broke.  Actually it was a garage sale find and the PO drilled a couple of holes along the back of it.  One hole was too close to the web and it bent/cracked when it was tightened.  I used cast iron rod, cast iron canned flux and an oxy-propane torch to repair it.  By the way the weld fused in to the base metal, it looked pretty much like cast iron.  Steel would not have melted with oxy-propane.


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## Ulma Doctor (Oct 29, 2020)

commonly you join stainless steels to weldable steel SMAW with E309L or E312L if you have no idea of the composition of either steel or stainless.
carbide precipitation is an unfortunate result of using a mild steel rod to join stainless steels.
the joint may not be as structurally resilient due to carbide formation in the weld pool
the clamps may work ok, just realize the weld zone is slightly compromised.


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## General Zod (Oct 29, 2020)

Two good all-purpose maintenance alloys are Hastelloy-W and Harris Super Missile Weld.  They are great for welding unknown and dissimilar steels based on what I've read.


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## cathead (Nov 4, 2020)

I was watching a You Tube video and this fellow was welding cast iron with 6013 welding rod wrapped with bare copper
wire.  I wonder if anyone on here has tried such a thing.  It appeared to work so might try it just for fun.


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## brino (Nov 4, 2020)

cathead said:


> I know they are not cast iron because if one puts enough force on them, they will bend(from past experience).



Here's a thread where I discovered a newly purchased c-clamp wasn't straight:
https://www.hobby-machinist.com/threads/straightening-a-c-clamp.39484/

With the guidance of the group I bent it back into shape without heat.
I have never seen cast-iron act like that.

That clamp is still working great.

-brino


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## ericc (Nov 4, 2020)

cathead said:


> I was watching a You Tube video and this fellow was welding cast iron with 6013 welding rod wrapped with bare copper
> wire.  I wonder if anyone on here has tried such a thing.  It appeared to work so might try it just for fun.



That is a very interesting trick.  I wonder what the metallurgy is behind that.  I have found that the old timers trick of using an oxy fuel torch to burn the free graphite out of the weld surfaces helps a lot for those troublesome jobs when the filler just won't stick.  I'll have to give it a try sometime.  It makes me think of corten steel, but this is something else.  Maybe it is like those nanoparticle crack inhibitors for welding those unweldable aluminum alloys.


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