Dan C
I'd like to use my Oxy/Ace torch to weld tong jaws onto the reins.  I used Crown #2 rods, and filled in a V shaped valley between the two.  When I tried to forge the weld area (brought to yellow hot in forge) it cracked apart as soon as I struck it.  Should I be able to do this, or is forging a gas-welded area not a good idea?  Any thoughts or info would be greatly appreciated.  Thanks!
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Skarzs the Cave Troll
It's possible to work arc welded welds up to a certain point, but even those will give out eventually. It may have depended upon how hard you hit it; I'm not sure what gas welds are like compared to arc welds in that area. Overall, one shouldn't work machine welds very much. However, if you don't want to do a lot of grinding, giving a weld a few hits to blend it to the two pieces should be fine.

Hopefully some other members can give a word or two.
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jmccustomknives
I have a very old book published in 1917 on welding with oxy/acetylene.  In that book it recommends forging all welds.  It is a good practice to forge even arc welds, high carbon steels benefit the most from using this technique.  Forging your welds is a technique that is all but lost now days. 

I had to check that alloy, the Crown #2 is a 70-s2 which is a tig rod.  You should be using a rod like RG-45 or RG-60.  I believe this is the root of your problem.  You also want to make sure your not running to much oxygen as that will weaken the weld.

This is the method for forging your weld.  After welding, heat the weld area back to no hotter than an orange heat.  Use a light hammer and refine the weld.  The idea is to refine and compress the grain growth that occurred during the welding process.  Work the weld down to dull red heat and stop.  This should make the weld very strong.

In that book I mentioned there is a picture of a guy torch welding a Model T's crankshaft. 

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Dan C
Thanks for your responses!  Very interesting!  I've only done a little gas welding, and I've never been happy with the puddle I was getting with the Crown 2 rods I was using.  I figured it was my lack of experience, but now I'm wondering.  James - Thanks for your very detailed comments.  I'm off to get some RG 45 rods, and will be giving the process you describe a try later today.
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jmccustomknives
Were you able to get that weld to set?

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Dan C

Here’s a progress report of sorts.  First, the RG45 rods made a HUGE difference in the quality of the weld bead I was able to run – for the better.  So that, in itself, is a giant step forward for me.  The bead I ran (right angle butt joint between two 6” long pieces) looks very decent.

 Next, using the RG45 rods, I welded a butt joint between the ends of two pieces of ½” square stock.  I ground the ends so that, when the two ends were pushed together, there was a V-shaped valley down to the center from two opposing sides (probably about 45 degrees).  The welding process seemed to go OK (but what do I know).  I ground away most of the excess and then lightly forged the joint as you described for a couple of heats.

 The joint looked fine.  I decided to see if I could forge it more aggressively, since I might want to do that in attaching reins to jaws.  I tried turning the ½” square bar around the weld joint into a round rod (with orange/yellow heat).  At first it seemed to be responding OK, but then I could see a crack developing, and then it cracked in two.

 So the question in my mind at this point is whether the weld failed because welds don’t like to be forged aggressively, or did it fail because of my lousy welding technique.

 Is the process I described a good one, or is there a better way to do a butt joint weld?

 Next step:  I’m going to do the weld again as I described above, but this time I won’t forge it.  Instead, I’ll cut it in two with a hacksaw to see what the weld looks like.  That may tell me something.

The learning process continues!

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jmccustomknives
What is the parent material? If it is a high carbon steel this could cause some problems. What did the grain of the steel look like at the break?  For forging the weld you don't really need to get it that hot unless the whole piece is brought to welding heat and proper forge welding procedures are followed.

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Dan C
The parent material is low carbon steel.  I just looked at the break more carefully and I think I made a cold weld.  I think I can see the unmelted surface of the parent metal.  This really surprises me, because I thought that I had really melted the metal in the joint.  Clearly I need to work on the welding process itself, which will start tomorrow. I'll keep you updated.  The broken weld material in the joint had a somewhat porous surface texture.
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Skarzs the Cave Troll
Looking forward to seeing your progress.
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Dan C
Here's a picture of my latest attempt.   (Still struggling with how to use the forum, so I hope this comes out alright.)

I cut through the weld I made with a hacksaw on a diagonal so I could see the internal structure of the weld.  As you can see, there is an internal fault.  The weld material was bright and shiny and looked the same as the stock material.  I'm quite happy with that.  

I'm thinking that the fault problem might be due to my setup process.  I ground a valley in to the middle of the bar on two opposing sides, filled one in, flipped the bar and then filled in the other valley.  On my next attempt, I'm going to make one valley all the way through the bar from one side and fill that in.  So, the learning process goes on...

half inch square bar 3-20-16.jpg
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jmccustomknives
I pulled this pic out of that old book.  Since it is 100 years old the copywright has expired.  Further down in the book it goes into more depth as far as procedure and such.  One thing it says about inclusions, too much oxygen.  You might also preheat the material before welding, this is suggested in the book.

I have only attempted torch welding a hand full of times as I have mig and stick welders.  DSCN4352.JPG 

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Dan C
Nice picture!  The torch is called a blow pipe.  Interesting.  I always preheat and use a neutral flame, so I think I was OK there.  Going to try making one valley all the way through the bar and see how that goes.  Each time gives me a little more practice and I think things are shaping up.
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Dan C

Latest update:  I made another butt joint with the valley going all the way through and when I cut it open it looked pretty good, so I'm feeling pretty good about being able to attach the reins to the jaws of a pair of tongs using my ACT/OXY torch.

What I did next was to make another butt joint, and then I tried forging it.  Using gentle blows on red hot steel I tried forging the 1/2" square bar into a round rod.  The joint failed almost immediately.  It just broke right in two.  I'm thinking, based on the limited experience described in this thread, that it's not a good idea to forge such a weld at all.  I think the weld is nice and strong, (based on the shiny steel I saw in the joints I cut in two) but hammering on it at all will weaken it severely.  My plan will be to grind and file the joint to finish it.

Thanks to Skarzs and James for your contributions to the conversation!  It's been an interesting process to go through.

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jmccustomknives
I'm not sure what's going on within the weld and why forging it is causing problems. 
Post some pics of what your making, we are interested now.  [wink]

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Skarzs the Cave Troll
Well, last thing I can think of is that the alloy is red hard and gets problems when forging at low heats. Thanks for sharing, Dan.
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Dan C

Yeah, actually it was yellow or what I would call a normal good forging temperature.  James!  Glad you're interested now![smile]  OK, so these will be my next steps.  I'm going to try again with a 1/4 in rod.  That will answer the forging question just as well, and will be much easier to weld correctly.

The other thing would be to have someone else on this forum try making the weld I described in detail above using an ACT/OXY torch with an RG45 rod - a good welder that could manage this weld.  And then see what happens when they forge it.  I think it's a good question to have an answer to.  We'll see how that develops.

Also, very important, I'll be out-of-town through next Monday, so I won't be doing any follow-up work on this till early next week.  I will have my computer with me however, so I'll be in touch with the forum.  Thanks for your continued interest!

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jmccustomknives
I think you may be getting it too hot.  Get a magnet and slowly heat a piece touching it as you go.  When the magnet stops sticking that is the hottest.  You want to start your forging just below that point.  Use light hammer strikes.  Your not trying to move any metal, just refining the grain.

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Hank Rearden
I'm following this.
code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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Dan C
Since I got back 5 or so days ago, I've tried doing a butt joint weld on two pieces of 5/16" rod (a couple of times).  For me, it's been a difficult process.  The whole joint area becomes liquid or semi-liquid and the liquid steel runs out and is lost.  I have no confidence that I've created a good weld.  What I've figured out is that this is not how I'm going to attach the reins onto a pair of tongs.  If someone else tries this and is successful in forging such a joint I would be very interested in hearing about the experience.  For me, I'm going to move on and work on such a joint by forge welding the pieces together.  I have a natural gas forge, so getting the steel hot enough is an issue, but I know I can forge weld with the forge, because I've done it a few times.  Thanks to all for your interest!
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jmccustomknives
There's more than one way to skin a cat.  There's other joinery methods you might explore.  Of course, there have been great advances in metal joinery in the last 100 years.  A little mig machine could speed up that learning curve. [wink]

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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anvil
My suggestion is to forge it to near final shape then do your weld. Grind or file the excess weld away but leave a little proud. Take nearly a forge welding heat and lightly forge to final cross section. This will get rid of all signs of your gas/arc weld and shouldn't break.

The probable reason you are having problems is you may not have a 100% weld. Any voids become cold shuts and will cause it to break.
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