Induction Annealing???

Discussion in 'The Ammo & Reloading Forum' started by Gearheadpyro, Nov 4, 2009.

  1. Gearheadpyro

    Gearheadpyro New Member

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    I recently purchased a heat induction tool for use both at work and in reloading. I use it in reloading to anneal my brass. There has been some skepticism as to whether or not a readily available heat induction tool would be able to heat a cartridge enough quickly enough to anneal only the neck and shoulder area of a cartridge. Let me put that to rest; it works. Not only that, it works very well.

    I am using a tool called the mini-ductor which is made for auto mechanics. Somewhat common tool for us, although it is usually a piece of shop equipment and not something the tech owns.

    I did an experiment tonight to show just how well it works. I took 7 pieces of unfired .308 Winchester brass of Winchester brand and put each piece into the coil for a different amount of time...

    [​IMG]

    I timed the heating with various counts, counts were probably 3/4 of a second on average.

    #0- Did not put into the coil, for reference only

    #1- In coil, power on for a count of 1. Very slightly made the neck more golden.

    #2- Power on for a count of 2. Starting to have spots that got hotter, slightly lighter in color
    than the rest of the cartridge.

    #3- Power on for a count of 3. Neck just ever so slightly turned pink at the very last instant of power on. I think that this one is just perfectly annealed.

    #4- Power on for a count of 4. Neck turned dull red for the last 1/2 count. I think this one is overdone but I could see where this one is what we are looking for.

    #5- Power on for a count of 5. Neck was bright cherry red, temperature started creeping down the case. After removing from coil a glaze formed on the neck (from overheating). This one definitely got too hot.

    #6- Power on for a count of 6. Neck, shoulder, and top of case body all bright cherry red. Heat moved even farther down the case body, same glaze as number 5. This one is cooked. I can deform it in my fingers.

    The verdict is that using a heat inductor is a very good way to anneal. Results were extremely repeatable and very fast. Cartridge #3 took about 8-10 seconds total between grabbing the case with pliers and heating it. I will be tinkering around with how to set it up to run automatically next. I'll be posting on my blog and on here with updates.
  2. woolleyworm

    woolleyworm Active Member

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    Nice and well laid out report. I've always thought about that as an option; I use inductance heating quite often and it does work very well; very consistent, repeatable and controllable heat patterns. I'll check out the mini-ductor and see what I find.

    Thanks for the post !
    Last edited: Nov 4, 2009
  3. JLA

    JLA Well-Known Member

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    3 and 4 are magnifico. Muy bueno. Whered you get the little dandy?
  4. Gearheadpyro

    Gearheadpyro New Member

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  5. Gearheadpyro

    Gearheadpyro New Member

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  6. Gearheadpyro

    Gearheadpyro New Member

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    I've put together another video showing my induction annealing setup, now with a timer. The timer was easy to build, and cost only about $15. I took the switch off of the inductor and plugged the wires into the timer. Now I hit the button to activate the timer, it turns the coil on, after a set amount of time it goes off. Simple as that.
    The schematic for the timer is in the video.

    http://www.youtube.com/watch?v=a_ohUknmaq4
  7. jdon72

    jdon72 New Member

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    Got to ask... why would you do this annealing process? Does it make the brass last longer? I do not use this process and therefor know very little about it. Good videos though...I have learned how to do it but still need to know why.

    J
  8. Gearheadpyro

    Gearheadpyro New Member

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    Annealing's primary purpose is to soften the neck and shoulder of the brass. This does many things;
    1. It makes the brass last longer, this to me is the primary advantage. As a case is shot and resized it work hardens, eventually enough that the case just can't take it any more. This is when the neck splits. Annealing softens the neck to prevent this splitting. It may still happen eventually, but it is a much longer life cycle.
    2. It improves neck tension. Correctly annealing a case makes all of the brass in the neck and shoulder area of the same hardness level, and therefore allows the bullet to be gripped the same on all sides. This prevents the bullet from being thrown off center when shot, and therefore improves accuracy.
    3. It improves cartridge sealing in the chamber of your gun. Because the brass is softer it is more easily able to expand to chamber dimensions. This results in cleaner fired cases, and a cleaner chamber in your gun.
    4. Annealing is also very useful if you are into wildcat cartridges that must be re-formed from other brass. Annealing softens the metal and makes resizing those cases much easier to do.
  9. jdon72

    jdon72 New Member

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    thanks for the info. You put everything into perspective.

    J
  10. JLA

    JLA Well-Known Member

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    stroke of genius my friend... I like it;)
  11. Gearheadpyro

    Gearheadpyro New Member

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    I've put together a slideshow/video with tempilaq on the cases. It shows how hot the cases get, and how localized the heat is. With the timer on the induction heater all of the cases get to the same heat.

    http://www.youtube.com/watch?v=Uasv-Pyxu4g

    Other than that...

    The automatic induction annealer is coming along well. I've ordered many parts for it and should begin construction within a week. I decided to go to a flashed chip for controlling it, that should help keep the cost down as I won't need a whole bunch of expensive electronics for it now, just the one chip. As always, I keep the updates coming on my blog, http://www.rifles-shooting-reloading.com/Reloading-blog.html.
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