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Heat Treating a Revolver

Discussion in 'Handguns: Revolvers' started by Tallball, Mar 25, 2015.

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  1. Tallball

    Tallball Member

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    In addition to my regular job, I also make knives. I have plenty of experience in heat-treating them properly. I heat them up in my kiln until they will no longer stick to a magnet, then I plunge them into oil. None of my knives has ever broken (as far as I know). I use high carbon 1040, or 440C stainless steel for the blades.

    I have an unusual situation. My FiL is my shooting buddy. His Dan Wesson revolver has developed a small crack in the frame, and since he his not an idiot, he no longer shoots it. I found a terrific bargain on a DW revolver and he is going to transfer the "guts" and barrel(s) of his into it, and thus have a safe and functional DW 357 again.

    I will thus have the leftover "innards" of a DW 357, a 4" barrel, and a frame with a tiny crack developing in it. My question is...

    If I heat up the frame enough to hammer the crack shut, then do my regular knife blade heat treatment on it, will the frame be okay to use?

    I am not willing to try this without expert advice, and THR is the best place for that, IMHO.
     
    Last edited: Mar 25, 2015
  2. dogmush

    dogmush Member

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    Short version: probably not. Almost certainly not.

    One could, theoretically, weld the crack up then re-heat treat and harden the frame. But you'd want to know a whole bunch of specifics about the alloy DW used, and how hard they got it. Then I'd want to have a hardness test done to see how close I got.*

    *I guess that also depends on where the crack is. There are less critical area's of the frame.
     
  3. tekarra

    tekarra Member

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    Heating the frame and hammering the crack shut will not repair the crack. The crack needs to be fused by some welding method. However, the heat input from welding will distort the frame to some degree. You will also need to know the frame composition to select the welding process and filler metal, if a filler metal is used. For me, repairing the frame would not be worth the time nor the expense.
     
  4. DPris

    DPris Member Emeritus

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    NOOOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!!!

    The cracked frame is junk.
    Denis
     
  5. Jim K

    Jim K Member

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    Where is the crack? It might not matter at all* and the gun can safely be fired with the crack. But as far as welding it or heating it white hot and hammer welding it, that would definitely be a bad idea; don't try it!

    *I recall a poster who reported a cracked frame on his brand new S&W. The crack ran from in front of the hammer, down back of the recoil shield and around under the cylinder and down in front of the trigger.

    Jim
     
  6. Tallball

    Tallball Member

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    I don't recall exactly where his crack is (lol), but my FiL is an engineer who researches everything he runs across, so I will take his word that it is not safe to continue shooting.

    And I will take everyone else's advice not to try another of my hare-brained schemes. :)
     
  7. Snyper

    Snyper Member

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    A good TIG welder could likely fix the crack without over heating the rest of the frame
     
  8. Tallball

    Tallball Member

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    Thanks for the welding suggestion. I will mention it to him Saturday (at the gun show).
     
  9. WestKentucky

    WestKentucky Member

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    In a word...no. please don't blow yourself up.
    Keep that extra gun basically as a parts kit. It is nothing more at this point. I would even go as far as to spraypaint it red to distinguish it from a serviceable gun.
     
  10. BCRider

    BCRider Member

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    From my understanding about welding it COULD be welded. But it's not an easy one pass over the crack sort of thing. It would need to be V'ed out and multiple passes used with the correct filler rod to fill in the crack. Along the way the frame would need to have the weld peened to correct for shrinkage by cold forming the weldment out to the right size.

    Then when it's all finished you need to get the repair machined back down to the right shape. Only then is it ready for a proper heat treating of the whole frame. And not just the hardening. The tempering back to the right spring like qualities needs to be done correctly to avoid further warping. If it's even possible.

    Your knife making has given you part of the equipment and skill set. I'm in the same boat. But when I looked further into all this stuff for heat treating I quickly learned that it gets a lot more specialized in a hurry when looking beyond simple knife making or machining cutters from drill rod like I typically do.

    All of this is a costly and time consuming repair which will likely cost more to have done than the frame is worth.
     
  11. Snyper

    Snyper Member

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    That would mean it's one HUGE "crack"

    What you're describing sounds more like joining a complete seperation
     
  12. BCRider

    BCRider Member

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    Cracks in something like a gun frame don't just appear on the surface. By the time it cracks it WILL be deep. And the weld will only penetrate about 1/16 to 3/32 inch. So that's why it would need to be V'd out so it can be fully welded from very near or at the apex of the crack and then back out to the surface. Otherwise the weld is just a bandaid over the remaining separation inside the frame.

    If the crack is so shallow that it could be filled in one pass then it suggests a crack which is so narrow that it would only be found with a dye penetrant test or with some other NDT method. Anything I've ever seen in metal of any sort which is visible to the naked eye is deep enough that it would not be fully repaired with a single pass.
     
  13. glove

    glove Member

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    "In addition to my regular job, I also make knives. I have plenty of experience in heat-treating them properly. I heat them up in my kiln until they will no longer stick to a magnet, then I plunge them into oil. None of my knives has ever broken (as far as I know). I use high carbon 1040, or 440C stainless steel for the blades."



    At what temperature do you draw the blades back to? Do you temper "Draw back" the blades after heat treating. What is your final RC scale hardness on the blades? If the blades are not drawn back they will be to brittle and prone to cracking.
     
  14. kwhi43@kc.rr.com

    [email protected] Member

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    I have heat treated several Ruger frames . They are made from 4140 and you
    want them to Rockwell 43 on the "C" scale. As I remember and this has been
    40 years ago, I put the frame in the oven at 1500 degrees for a hour then into
    oil. After cooling back into the oven at 400 degrees to draw it back to Rockwell
    hardness of 43. Hope this helps.
     
  15. marv

    marv Member

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    I did some welding in a past life. In my experience a gun frame is so small and the metal so thin that the mere act of striking an arc would blow away half of the gun. And I wouldn't let a torch near a gun.
     
  16. Tallball

    Tallball Member

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    Thanks for all of the good advice. I am not going to attempt this project. It was just a (bad) idea I had for a few moments. My FiL will just keep have to keep his eyes open until he runs across another frame at a reasonable price.

    After I clean the blades up I heat them to 400 for a couple of hours, let them cool back down to room temperature slowly, then do repeat it once. I don't have proper testing files, but I just now tested one of my 440C blades. The Rockwell 45 file doesn't seem to mark it, but the 50 does.
     
    Last edited: Mar 29, 2015
  17. Snyper

    Snyper Member

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    You're describing "stick welding"
    TIG is much more precise and easy to control
     
  18. BCRider

    BCRider Member

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    Marv, it sounds like all the welding you did was with big bad welders, heavier sticks and bad torches.

    I think you'd be amazed at what can be done even with stick welding with the right electrode choice in the smaller 1/16 sizes. And then TIG raises the bar on the possibilities to a whole other level. Check out You Tube with the search terms "tig pop cans" to see what I mean. It's an eye opener that'll make welding a gun's frame seem pretty simple by comparison.

    There's also one from Larry Potterfield where he TIG's some build up on a Parker shotgun's barrel hook that again shows how TIG can be a gunsmith's friend.
     
  19. TimSr

    TimSr Member

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    JB Weld!!!
     
  20. PapaG

    PapaG Member

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    Unless you know the chemical composition of the frame, have access to the heat treat specs for the frame and can duplicate the process to get it the same and have a way to keep the frame from warping while welding, I think you are peeing in the wind on this one. Heat treating a knife is a little different in that it doesn't have to contain thousands of pounds of pressure repetitively.
     
  21. JDBoardman

    JDBoardman Member

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    If the crack is in the frame, and not in the area under the barrel (where revolvers typically crack), a repair is possible. First, do a Rockwell hardness test to get the basic frame hardness, then weld, remachine, and heat treat. Rule of thumb is 1500 degrees F for 1 hr. per inch or less of material thickness, oil or brine quench, and draw at 300 to 400 degrees F and cool to final hardness. GTAW (TiG) is the only welding process practical, and it would be best to anneal the frame before welding to minimize warping. It is absolutely essential that you know the alloy the frame is made from so you can specify the proper filler material (autogenous welding is not a likely candidate); what the heat tratment and stress relief regimens are, and verify the weld integrity through X-ray to get a successful repair. Oh, yes - a refinish will also be required. Like I said, the repair is technically possible. Possible; yes... feasible; without specialized tools and knowledge, not likely.
     
  22. BCRider

    BCRider Member

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    Adding to JD's post is that when heat related warping needs to be minimized it's also normal to pre-heat the item so that the heat of welding isn't adding as much and it can all cool and shrink together. The shrinking of the weld that causes the warping comes from it being so localized and because it melts into the base metal and then shrinks as it freezes again. Pre-heating both aids in a little more penetration as well as expanding the frame before the welding is done so the freezing of the weld pool isn't as big a shock and it can then all cool and shrink more evenly.
     
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