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Discussion in 'NFA & Class III Discussion' started by Hump66, Aug 17, 2012.

  1. Sanjuro82

    Sanjuro82 Sharpshooter

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    You'd have to take the steel to critical which for 4140 or 4150 would be between 1550-1600 degrees. Then to anneal the steel you have to allow it to cool very slowly over a number of hours.
     
  2. Shadowrider

    Shadowrider Sharpshooter

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    Only to reach 100% total heat saturation. Then like Sanjuro said, cool it very slowly over a number of hours.

    Tempering and anealing are as different as black and white.

    If you are losing hardness (temper) you have gotten to critical temp. If you use a torch it's quite easy to get the surface and slightly below it (where you hardness testing it later) to critical. That may be why you've seen it happen. Also that's why almost every heat treat specification I've ever heard of specifically forbids open flame furnaces, among a myriad of other reasons. You can put the barrel into an electric oven and subject it to no more than 1100° and leave it for days. Cool it down slow, and you won't lose any hardness.

    Good idea, if you can control the heat.
     
  3. Shadowrider

    Shadowrider Sharpshooter

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    lol. I hear ya, that chit's soft and stringy. The only way to get it shiny and purdy is to use coated carbide and run 900-1100 SFPM. Damn near impossible to do on a manual engine lathe. One of the 1213s is much easier to machine nicely.
     
  4. Hump66

    Hump66 Sharpshooter

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    Well, I've tried 3 times now with the silver solder with mixed results. Each time it holds better, I guess I'm just paranoid about damaging the barrel. Now I'm wondering if the multiple heat/cool cycle could have done anything. Any thoughts?
     
  5. HiredHand

    HiredHand Sharpshooter

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    Hump66, maybe you need some TempLac or similar product.
     
  6. HiredHand

    HiredHand Sharpshooter

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  7. Hump66

    Hump66 Sharpshooter

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    I think for the $128 markers, I'd just take it to a gunsmith. Those are a cool product though. I think I may try once more and then order the tempilaq liquid.
     
  8. HiredHand

    HiredHand Sharpshooter

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    I thought you had to use silver braze for permanently attaching the muzzle device.
     
  9. Hump66

    Hump66 Sharpshooter

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    silver solder is what the ATF requires. I bought a syringe of it in paste form, just smear it around the threads and heat it up.
     
  10. tyromeo55

    tyromeo55 Sharpshooter

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    What are you using as a heat source?
     

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