Induction Annealing???


November 4, 2009, 08:25 PM
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...

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.

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November 4, 2009, 08:57 PM
I would say that #4 would be the proper annealing temp. You need the dull red briefly to change the metal.
That is a neat tool, but too much $ for me. I'll just use my torch and the pan of water like I have for the last 40+ years.


November 4, 2009, 09:20 PM
well now I learned something new and can call it a productive day....

thanks for posting your discovery

November 4, 2009, 09:40 PM
I like #5, it looks like the Old PMC stuff I used to shoot.

How did you cool the necks??

November 4, 2009, 09:56 PM
Air cooled the necks. #5 got too hot, although if I wanted to have the heat go a little farther down the body I could just lower the coil or spread it out some more. That would be easy enough to do.

November 4, 2009, 11:16 PM
That screen name fits you. How is the induction unit powder? 110V I assume.
The link doesn't show much, but I am searching on the net.

Pretty cool stuff. I'll be looking to anneal some brass in the future.


November 5, 2009, 06:55 AM
WNTFW, thanks.
110V, 1kw.
google "heating inductor" for videos. There's lots of them out there although most of them are for large scale commercial units.

Ed Harris
November 5, 2009, 09:28 AM
That is how they do it at LC. 3 seconds on a 7.62, 2 seconds on a 5.56, 4 seconds of a cal. .50 BMG

November 5, 2009, 11:15 PM
Now that you mention it, I think I saw that listed in an article on S.C.A.M.P.

November 5, 2009, 11:18 PM
Does LC have a website? Or does Federal have one for LC. I can't really find any information on them other than on forums and the like.

November 6, 2009, 09:30 AM
I don't think Lake City does, but I never even thought to look. I found some info on SCAMP on line. IIRC they were going to anneal the neck using lasers but went to induction for whatever reason. It was either time or even heating.
The flame is easier to implement quickly but the induction method seems like it would be better in the long run. Open flames aren't always cool (no pun intended).
Thanks for posting you findings. Or a sarcastic "Thanks" because now I am becoming obsessed with using induction heating to anneal. Never mind I have a torch and hav not annealed any brass yet anyway.

I am also interested in your "Load Code" or whatever you had on one of your targets. Do you have a method and if so has it worked out well. Pros & Cons of your method would we appreciated.

Thanks again.

November 6, 2009, 04:55 PM
# 3 looks good. Good tool if you already have it but you could build an automated annealer for less cash.

November 6, 2009, 07:16 PM
jmorris: I am working on development of an automated induction annealer that I will hopefully be able to build for ~$400, in the same ballpark as the other commercially available propane annealers.

WNTFW: Your welcome, seems like you were bit by the bug too huh?
I don't know what SCAMP is? do you have a link?

The load code written on my targets is how I know what is in the bullet. It is something I came up with very similar to a vin number or part number on a car part. The load code has a master worksheet that I have made...

It just makes it easier for me to keep track of what I've loaded and its performance. All of my records are in that notebook. Each lot of 50 pieces of brass I have goes into a labeled plano ammo box (my "lots"), and each lot of ammo gets a load card filled out for it. That has all my information on it like the load code, the number of times it's been fired, etc...
Each range card has a place to put the load code and lot number, together I know everything about that bullet.
It's a system that works for me, and it is what I am used to. I could see where some are sitting back and saying Why? To them I will say, because I am entirely anal about perfection, and that's just how I roll.

November 7, 2009, 01:13 AM
Google this:
"Small Caliber Ammunition Modernization Program"
Has about 15 page of acronyms

No big deal really I just ran across it while researching some .223 headstamps. I didn't read a whole lot on it & probably forgot a lot of what I read.

Your "Load Code" is cool. I'd rather be positive and I'm pretty live & let live, so no negativty from me. I also have had nightmares about developing a truly great load and not documenting it. In reality I develop OK loads and don't lose the documentation. Having a code, conventions or at least a set way is good.

On a similar note my neighboor & I both reload .223 & .308 and compare notes. We have had the same findings & work together on "Stuff". We go to the range together often.

November 7, 2009, 07:34 AM
jmorris: I am working on development of an automated induction annealer that I will hopefully be able to build for ~$400, in the same ballpark as the other commercially available propane annealers.

Thats going to be pretty tough when the Mini-Ductor in your link is $370 by itself, or is there a better source?

As for your automation project I am always interested in projects like that. The one I built uses the torch method but is "hands free".

November 7, 2009, 02:34 PM
Jmorris, I've seen the videos of your annealer. That is awesome.
I won't be able to use the miniductor in my annealer as it is too expensive, I will be building my own induction heating circuit. The circuit itself is fairly simple, so I'm not expecting major issues there. Hopefully by building the circuitry myself I will be able to get it into the correct price range. All of that is in the works.

November 7, 2009, 10:48 PM
Oohh... I gotta keep on on this!


November 8, 2009, 08:40 AM
I won't be able to use the miniductor in my annealer as it is too expensive, I will be building my own induction heating circuit.

Now you have to provide more information along with some photos.

November 8, 2009, 11:30 AM
Plenty of info on the net. Neat. Might have to play with this some.

November 8, 2009, 12:29 PM
New Mini-Ductor II

This looks good -


November 8, 2009, 01:37 PM
Not good... AWESOME. Wish I still turned wrenches with a tool like that!


November 8, 2009, 03:33 PM
I put together a short video showing my setup and how I do it.

Induction annealing video (

November 25, 2009, 11:10 PM
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.

November 26, 2009, 11:55 AM
My mind just dances with ways to make it automated.

I'll be waiting for video of that! :D


November 26, 2009, 09:11 PM
Very nice set up. Making me re-think my desire for a Ken Light BC1000 :)

December 20, 2009, 09:41 PM
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.

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,

December 20, 2009, 11:59 PM
I sure hope this turns into a product that you can market....


December 21, 2009, 12:59 AM
The inductor tool for heating stuck bolts comes with one free "miniductor" coil. Runs on 110V and 1KW power. Fellow over on said he sets the induction "On" time for various calibers using the temp-laq sticks to calibrate, then operates in batch mode using an old photo enlarger timer. Anyway, the complete rig new is $475 MSRP. I wonder what a group buy would be. I am going to check with my friendly Fastenal store nearby and see what Chinese version is available. I like the quick clean heat, no open flame idea.

December 21, 2009, 01:44 AM
Looking at the video, it looks like you're going too hot.
Get the heat crayon from a welding shop to get the right temp.
I've found that if I get the cases hot enough to see red, the brass is almost dead soft, something you don't want.
You might check it.
It does look fantistic, now just figure out how to automate it and I'm sold.

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