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Forge Welding resist


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Strange question I know, but I will be taking a class shortly where we will be forge welding sockets made out of real wrought iron as one element in a larger project.  I have been doing a little research and found that most folks who forge weld sockets or tubes use an inner mandrel during the welding process to keep the crossection stable and allow hammer blows to be concentrated on the welding plane.  To avoid sucking the heat out of the stock, the mandrel appears to be heated up with the stock to something approaching welding temperature.

So the question is: How do you avoid welding the mandrel  into the socket?  I know that a layer of paint containing some titanium dioxide (White-out) is reputed to work well as a weld resist, or a significant layer of scale, but are there other alternatives that folks have used?  Specifically I was wondering if spray-on dry graphite lubricant might be effective.  

I do have a mandrel and matching bick that I forged out to use in the class, so I may try it this weekend.  However I would appreciate some guidance from smiths more experienced than I am with forging sockets or tubes.  I may be overthinking this...

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Steve,

That is a great idea, and I can't believe that I didn't think of it.  We will be using coal forges, so there should be plenty around.  Of course at home I don't have my coal forge setup yet (struggling with getting a proper thimble for the roof penetration), so I will either need an alternative or get myself a can of coal dust next time I'm at our local group forge.

Thanks!

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The old damascus shotgun barrels as well as early flintlock rifle barrels were made by forge welding around a cold mandrel.  I suppose cold is a relative value but there has been a bunch of pattern welding/forge welding done on a cold anvil.  

 

 

 

 

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I recently watched a video where the smith forge welded a socket on a cold mandrel and I've forge welded wrapped axe eyes with a mandrel in place. Maybe the heat sink isn't as significant as one would think. Coal dust sure can't hurt. 

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Sorry late to the party..  

There are actually several different ways..   

the one that I use often is to use stainless steel as the mandrel..  

If I am doing barrels or the like the mandrel is kept inside the barrel as its coming up to welding temps just shy of the are being welded..  Then just before the tube is brought out it gets driven in some and the weld is made, then mandrel pulled out and trued and put back in..   

This mandrel job is done by the helper.  Pulling the rod out and straightening and truing it cools it and allows for oxides to form on it before being put back in.  Wrought iron is super easy since it's got flux in it.. 

2 people knowing the job this can work very quickly..  Very, very quickly. 

And lastly Using the welding flux can work and is one of the primary things done making hinges..   The hot flux once it oxidizes won't weld to itself..  You can also use clean sand. 

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Thanks Jen.  Very helpful as usual.

Here is the bick I forged up to help with final shaping (and possibly the forge weld, depending) as well as the rough forging on the mild steel mandrel I forged out.  The latter is now ground clean and polished up to match the bick.  Both made from 1 1/2" stock.  Bick was 4140 and has been heat treated.

finishedbick.thumb.jpg.7b31456f70dfa0bfa7726fb89932d765.jpg

roughforgedmandrel.thumb.jpg.03e3166c6dbf015d1f6d0358bb27b6e1.jpg

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I'm just guessing here, but I suspect that since the success or failure of a forge weld is determined in the first couple of hammer taps, a room-temperature mandrel isn't going to be in contact with the socket long enough to suck out enough heat to jeopardize the weld. Just make sure you're using the magic welding hammer. ;) 

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Hi Dan can you be more specific as to the tube or socket that you're actually trying to weld?

Hi Tomahawk sockets are very easy to do because of the size of wrought iron.

Depending on the wall thickness will determine what method is best utilized.

 

1/4-in wall thicknessing up is super easy.

 

1/8-in size and down is kind of tough.  The heat reserves just aren't there for the smaller sizes. If using smaller sizes really the mandrel does need to be heated with the item when welding or else you really have to be fast to get it on the mandrel and be sure to preheat your mandrel. 

By the way it's nice that you're thinking about these things before the class or before the activity.

 

More than likely the instructor will have a method that they want to use. 

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I also suspect Emiliano will have everything all worked out and I will follow his direction. However, it is a full class and I am trying to bring extra tooling for myself so I won't experience a holdup waiting to share tools from a limited stock.  Of course, Emiliano might pull a Jim Austin (fantastic teacher BTW) and bring enough tooling for each student to have a set, but this way if I have guessed right I'll be prepared to make more sockets at my home forge.  In any case it was a good exercise to make the bick and mandrel.  I'm really excited about forging socketed tools (everything from wood working chisels to shovels).

This will be the Viking Pattern Welded spear class at NESM.  I strongly suspect that we will be using wrought iron for the sockets and the initial thickness will be somewhere in the range of 1/8" to 1/4", but can't be sure.  I agree that the thinner stock will be tougher to keep at the right temperature long enough to get to the bick, so that is why I also made up a mandrel and was asking about resists.

42 minutes ago, JHCC said:

magic welding hammer.

Already packed.  Don't leave home without it...  

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Welding socketed tools is a lot easier than most people think.

 

Where most people run into problems is at the junction between whatever the tool is and then the fold over and then not having adequate scarfing or too much scarfing for the weld.

 

That answers a lot of questions but you're also going into one of the easiest types of welds.

 

Everything is held in place for you while you're welding The biggest thing you have to remember is that you have to undersize the socket for whatever your finished socket size is.

 

Also with modern grinders today belt grinders once your sockets welded you can just clean it up on the belt grinder with a slack belt.

 

Forge to finish is what I prefer if possible. 

You shouldn't have a problem at all. 

You'll have a great time for sure. 

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