Induction heating for case annealing?

[6bg6ga]

I don't know if this belongs in here or not but since this is a case forming/reforming section I thought it would fit right in.

anyway.....

Looking at making an induction heater to aid in annealing case necks of rifle cases. Anyone else used this process? Any thoughts? I've watched the videos of those automatic annealing machines and I'm not really impressed with them. One thing I don't like a torch or a dual torch setup because of the possibility of a torch falling over and starting a fire.

My idea is to construct a simple induction heater with a timed cycle that one can set. Annealing as I understand it is a simple yet understood process. Too much heat and you turn the neck cherry red and possibly case damage to the metal and too little heat and the time you have spent doing the process is wasted. If I understand the process you want to heat the neck to 700-750 degrees. There is a compound out there that can be put on the cases and it burned at this heat point showing that the case is heated correctly. Anyway I'm thinking of a simple unit that would allow one to position the heater above a single stage reloading press and put a case in the case holder and simply run the case up into the heater coil to expose the neck to the heater and cycle the heater and adjust the run to in order to get the correct temp reading. Once that happens you simply lower the case and remove it. The second idea is to construct a simple machine that you load with cases and it anneals them and spits them out.

[ubetcha]

I like that idea. Sounds like it could be done fairly easy. The down side is, of all the induction units I have seen from the automotive tool dealers ( Snap-on, Matco, Cornwell, etc), they are expensive. At least for me anyway. $300 to $400 dollars. But if one could put it on a timed circuit like you stated, the consistence of applying the heat would probably work out great . Some one with electrical circuit knowledge can come up the a timer design I'm sure. I will watch this post with interest.

[btroj]

Even a coil you could just insert the neck into by hand. I prefer to do it that way. Lights off, watch for a hint of glow and pull the case. Once I know the time for that I simply count. By holding the case with my fingers I also ensure the head never gets beyond warm.

How much would a coil run? Is this a battery thing or plug in?

Interesting idea.

[ubetcha]

The ones I saw were plug in a/c voltage.

[6bg6ga]

Even a coil you could just insert the neck into by hand. I prefer to do it that way. Lights off, watch for a hint of glow and pull the case. Once I know the time for that I simply count. By holding the case with my fingers I also ensure the head never gets beyond warm.

How much would a coil run? Is this a battery thing or plug in?

Interesting idea.

This will be a plug in 120vac power supply. It will be a 120 primary transformer with a secondary of 12-24volts with will be rectified to provide DC voltage to run the heater.

[ubetcha]

I was watching some videos that showed induction heat treating and it take just seconds to heat an object in the coils magnetic field

[TheDoctor]

http://youtu.be/a_ohUknmaq4

Just found this. Would be way cool if it could be set up on a presa with a automatic case feeder.

[ubetcha]

There we go! Some one beat us to it. I think it worth a try. But need to get the timer schematics.

[Love Life]

I looked into doing this a year or two back, even started a thread on it in the projects sub forum, but didn't follow through. The price of an induction heater paid for a whole lot of MAPP or Propane and I have been happily and safely annealing ever since.

Here you go: http://castboolits.gunloads.com/showthread.php?215173-Annealing-brass-with-an-induction-heater-tool

[texassako]

It looks pretty cheap to make one if you know your way around a soldering iron. Here is a pretty simple one: https://www.youtube.com/watch?v=pVYMLnXW9uo and the write up: http://www.rmcybernetics.com/projects/DIY_Devices/diy-induction-heater.htm I might have to add this to my list of future projects.

[dragon813gt]

Neat idea but that's a lot of upfront cost. I wonder what the duty cycle is on the heater? Can't be more than 50%. Most likely a lot lower.

I like the idea and w/ the right jig setup you will have consistency. Basically create a floor that slides out. Drop the brass in from the top. Slide the floor out at the end of the timed cycle. You'd basically just be moving the coil up and down for different case heights. I don't want to stick my hands anywhere near the coil.

I've been eyeing up one of those BenchSource annealers. They're proven, this is not :(

[Love Life]

Yeah, I just bought some MAPP, 900 degree Tempilaq, 400 degree tempilaq, and went to town. Dumping into a bucket/coffee can of water/citric acid mix removes any scaling and tempilaq and after tumbling you can barely tell the brass has been annealed.

[Doc Highwall]

Here you go with the latest and greatest.

http://www.ampannealing.com/

[GRUMPA]

I think for there $1K asking price.....I'll stay with my Ken Light annealer.....

[dragon813gt]

That's directed at the Benchrest shooter since it only goes up to .338. Price tag will keep most from buying one. It's twice the price of flame annealers. And unless you're shooting for thousandths of an inch I don't see how any added consistency would benefit you.

On the other hand if you don't want to deal w/ open flames and don't mind the cost. Then it seems like a good option.

[s mac]

A diesel eng glow plug would be another possiblity, 12V, relatively inexpensive. Figure out how to duty cycle it, shim the end to fit snugly in the case neck.

[country gent]

We had them available in the tool rooms I worked in to heat bearing to swell them and intall on shafts. Worked good for that and was quicker more consistant than a tourch or oven but they were very expensive units. I think the one was around 600.00 or so. Also keep in mind they dont discriminate between bearings cases rings watches metal chips. Its an interesting Idea and I thought about it once and never went any farther.

[6bg6ga]

Guys it doesn't cost $995 or 600 or even $300 to make this. I've already thought on the timer circuit and have the problem solved. Worried about duty cycle? Don't be because the coil can be cooled via a set of cooling lines a pump and a radiator.

[6bg6ga]

A diesel eng glow plug would be another possiblity, 12V, relatively inexpensive. Figure out how to duty cycle it, shim the end to fit snugly in the case neck.

A diesel glow plug isn't going to work.

[6bg6ga]

It looks pretty cheap to make one if you know your way around a soldering iron. Here is a pretty simple one: https://www.youtube.com/watch?v=pVYMLnXW9uo and the write up: http://www.rmcybernetics.com/projects/DIY_Devices/diy-induction-heater.htm I might have to add this to my list of future projects.

Your part way there. This unit is crude but will work when coupled with a correctly designed cooled coil with a timer and a decent power supply rated at 6A or more.

[s mac]

A diesel glow plug isn't going to work.
Why not?

[texassako]

Why not?

They are toast in as little as a minute of being on, depending on brand. Plus it is going to take a lot of time for the heat to cross that air gap to the case.

[s mac]

They are toast in as little as a minute of being on, depending on brand. Plus it is going to take a lot of time for the heat to cross that air gap to the case.
I don't want an argument, I've never timed on out in the open to know for sure but I work on diesels everyday and would have thought that they were more durable than that.

[6bg6ga]

I don't want an argument, I've never timed on out in the open to know for sure but I work on diesels everyday and would have thought that they were more durable than that.


Read up on induction heating and you will have your answer.

[Ballistics in Scotland]

I lathe-turned a hollow copper bit, chamfered to approximately fit the case shoulder, for a large electric soldering iron.

[6bg6ga]

I lathe-turned a hollow copper bit, chamfered to approximately fit the case shoulder, for a large electric soldering iron.

Your large soldering iron may work but its not going to be as fast or accurate as induction heating. In induction heater acts to heat up the metal that is inserted inside the coil. This happens very fast. Placement inside the coil doesn't need to be accurate either and generally a coil that will do the job is in the neighborhood of 1" inside diameter.

[kencha]

I built an induction heater based on http://www.rmcybernetics.com/projects/DIY_Devices/diy-induction-heater.htm a couple of years ago. It is not the most robust setup but will work within its limitations, and water cooling is a must, even with a low duty cycle.

Then built a case feeder like shown on many youtube videos, used a couple of stepper motors, a gripper, and an arduino inside an old computer case to build a functional automated annealer. More of a proof of concept and playing with an arduino type thing than something production worthy. In other words, it works but is borderline Goldbergian and isn't going to win any beauty contests.

[s mac]

Read up on induction heating and you will have your answer.
I defer to you sir.

[6bg6ga]

I built an induction heater based on http://www.rmcybernetics.com/projects/DIY_Devices/diy-induction-heater.htm a couple of years ago. It is not the most robust setup but will work within its limitations, and water cooling is a must, even with a low duty cycle.

Then built a case feeder like shown on many youtube videos, used a couple of stepper motors, a gripper, and an arduino inside an old computer case to build a functional automated annealer. More of a proof of concept and playing with an arduino type thing than something production worthy. In other words, it works but is borderline Goldbergian and isn't going to win any beauty contests.

As I pointed out in a prior post the coil is going to need to be cooled. This means a pump, coolant lines, and a radiator. Also the work coil needs to be redesigned. These improvements along with a decent power supply and a few circuit modifications WILL result in a workable induction heater.

[texassako]

As I pointed out in a prior post the coil is going to need to be cooled. This means a pump, coolant lines, and a radiator. Also the work coil needs to be redesigned. These improvements along with a decent power supply and a few circuit modifications WILL result in a workable induction heater.

The bottom of that website has a taking it further section with a cooled coil using a repurposed cpu cooler as a pump and radiator.

[6bg6ga]

A cpu cooler isn't going to do it

[nanuk]

Guys it doesn't cost $995 or 600 or even $300 to make this. I've already thought on the timer circuit and have the problem solved. Worried about duty cycle? Don't be because the coil can be cooled via a set of cooling lines a pump and a radiator.

I didn't think the coil got that hot...

I watched a video on Savage actions where they used induction to heat treat the receivers. FAST! only seconds to get the receiver glowing! Heavy coils and HIGH Power!

[nanuk]

They are toast in as little as a minute of being on, depending on brand. Plus it is going to take a lot of time for the heat to cross that air gap to the case.

on my Uncles IH tractor, I'd hit the glow plug and count to 300 before hitting the starter. On my 560, I'd count to 200. Never had one burn out.

[6bg6ga]

I'll bet the glow plug would take a long time to try to heat anything up.

[WRideout]

As a certified skinflint, I am always looking for the cheap way to do things. When my wife wasn't home, I tried using the flat glass-top stove to anneal cases. I just stand them upside down on the burner, turn it on high, and let the cases cook until there is some color change just to the base of the neck. It happens much faster than you would think, and takes some careful observation. One time, I had a batch of 30-06 cases I let go too long, and they changed to a bluish color, all the way to the head. Reluctantly, I consigned them to the scrap bin, since I couldn't trust them to have the strength they used to.

Wayne

[GREENCOUNTYPETE]

timers are not that hard , but no point these Aduino http://www.amazon.com/UNO-Board-2012-Mega328p-atmega16u2-Cable/dp/B00CW3R0BA/ref=sr_1_4?s=electronics&ie=UTF8&qid=1423071768&sr=1-4&keywords=arduino+uno+r3+board
open source controllers are so cheap and easy to program that my 11 year old son had his first program written in 30 minutes and allow for .001 second adjustment just by changing the value in your program , plug in the usb cable re-download and change is made you can also use sensors and automate it , it is all very low voltage but you just use it to control the relays that handle the real power , some delay in relays but much less than the variation limits you will need.

you find a coil that will heat the brass to the desired temp , figure out how long that takes automation isn't hard probably can even make it with a solenoid so that when the heat cycle is over it drops it into the water as part of the timed event

I did a lot of relay logic stuff back in school then learned Alan Bradly programmable logic controllers they were awesome you could do just about anything with them , obviously that was their point to control prossesses through electronic input output switching of industrial machines , but they were cost prohibitive , these UNO boards program a lot like an Alan Bradly PLC but are under 20 dollars you have limited input outputs but enough for simple tasks

my brother got me started on these he uses one to control his automatic beer bottle filler

[bangerjim]

An induction heating coil runs on AC power not DC. Most circuits floating around the net show converting higher amp DC to pulsed AC for the coil. 200Hz or so seems to be good.

Sticking a neck in a glo-plug is NOT induction heating. No different than sticking it in a toaster or putting in on top of a stove heating element. Any heating there is by radiant transfer, not induction.

A transformer is an induction device and, as you know, will not function on DC power. Same with the induction heating process. The alternating field created inside the coil excites the molecules of the brass (or whatever you stick in there) to a higher temp. You don't really even need a timer. Just a pushbutton for the oscillator circuit power and count 1001 -1002 - 1003 until you get an idea of how long to hold the button down for annealing required. Now that IS cheap!

What's next? Someone trying to heat brass necks with one of those induction cook tops? Not gonna work. Those require ferrous metals in the pan to trigger the circuit and then heat it up with AC induction power.

The small circuit and coil in the web link above is about the best I have seen for very little money. And the coil itself should not get overly hot if the thing is designed right. No need for fancy liquid cooling loops, radiators, and the such. After all, the whole idea is to put the EMF power into the thing you are heating, not the coil.

I have not tried brass annealing in a home-brew induction heating coil. Since brass is non-magnetic, some experimenting will probably be in order to make it work efficiently. But there are videos showing home-brew set-ups doing it quite well. Commercial induction soldering of non-ferrous metals works very well.

banger

[6bg6ga]

The circuit that was posted relies on a transformer whos output is rectified and filtered to power it. To go past that is to confuse most here. The circuit inputs a single 15vdc supply and ground. The circuit also used a regulated 15 VDC supply for the fets.

[Frank46]

Saw a video on Ruger handguns. Showed an induction heater that heated the barrel when they attached the front sights. That section of the barrel was red hot long enough for the solder/silver solder or brazing compound to melt and then the barrel and font sight are basically one piece. And looking at the breech end of the 10-22 rifles in some pics shows heat discolorization most likely done with an induction coil. Frank

[ReloaderEd]

shooters at our range have gone together as a group and purchased one of the manufactured units. It works very well and they are excited about the bullet pull consistency of the annealed necks contributing to much better accuracy.

[popper]

The coil is copper. Brass & copper are not magnetic so the coil & brass temps will be the same. Coil needs to be cooled. Ferrous metals induction heat very easily, brass not so easy.

[Mr_Sheesh]

I've seen quite a few inductive heating coils made of copper tubing, water flowing through it will cool it nicely. They used to use a 555 timer IC but (IMO) the microcontroller such as an Arduino (Uno or even the Mini's that are only $2-$3) is a far superior answer - You get reliable and far more accurate control. On the other hand you could make a flame type annealing setup with a valve that would shut off the gas, should the unit fall over, or just make it so it is unlikely TO fall over (bolted or clamped to something solid, for example.)

[Yooper003]

With that big plastic base for 16 oz. propane that comes with Coleman lanterns, it is very hard to tip over. Sill like propane torch with socket that cas will fit in & electric drill

[Blitzfike]

For those intersted in cheap chinese stuff her is a link. I have played with three or four different models they offer and the power supply is the critical element. You need your power supply on and working before you power up the induction unit. I've let the smoke out of a couple of them so far. https://www.banggood.com/search/induction-heater.html Edit to add that I use a TIG water cooler forf the big unit's coil. Keeps it cool as can be. One of the smaller units uses a fountain pump for cooling water.

[Mr_Sheesh]

You can sometimes find better deals at aliexpress; Sadly some electronics parts aren't made in the US any more.

[JeepHammer]

Some things you should probably know...

Tempilaq (thermocromatic paint) isn't accurate.
It uses both copper & zinc in it's makeup and the cartridge brass screws with it, I got this directly from a Tempilaq tech.
If you want to prove it to yourself, paint one side of a case with 750*F and the other side with 800*F and heat.
The 800*F will change color first every time.

There are two ways to control the energy delivered to the case,
Either you leave the coil on full time and control the TIME the case is in the coil,
Or you control how long the unit runs, switch it 'On/Off'

Most of the surplus/discount units are for 'Solder Pot' applications or heat sealing.
They come with tubing for cooling, and these units normally don't live long when you cycle (switch them On/Off)

Some come with solid core wire, or flexible wire & Ferrite core.
These are usually built to switch On/Off (cycle) since they don't have provision for cooling.

You will find the tubing & solid wire versions are VERY hard to keep the annealing in just the neck/shoulder area, it's a wide open coil, the magnetic field is hard to control.

The stranded/flexible wire (usually Litz wire) and a slotted Ferrite core will focus the magnetic field between ends of the Ferrite MUCH better and concentrate the power of weaker units.

AMP, Fluxeon 'Annie', etc use a Ferrite, and use digital timers for cycling.

The 'Annie' will take the case shoulder/neck completely off a .223 or .308 case in just a few seconds.
.223 slag is about 8 seconds, while .308 is closer to 12 seconds.

Keep in mind I had to 'Detune' my Annie, it didn't allow enough saturation time for the annealing process to happen.
I didn't own the AMP long enough to get that far, it has 'Programs' instead of direct read time, and the power supply isn't tuneable, it's full power 100% of the time it's on...
The ONLY adjustment you get is time.
'Annie' has the better timer simply because it's direct adjustment/read. (And it's about 1/4 to 1/3 the cost of AMP)

This is a surplus 'China' unit, does OK as continuous 'On' but doesn't like being cycled. I've killed a dozen of them, but at $30-$40 each they are cheap enough to experiment with.

http://i1298.photobucket.com/albums/ag58/JeepHammer1/IMG_02351_zpsrrsncvs5.jpg (http://s1298.photobucket.com/user/JeepHammer1/media/IMG_02351_zpsrrsncvs5.jpg.html)

I STRONGLY suggest some fiberglass wrap for coils no matter what you wind up with.
Pretty easy to get a case against bare conductor and short the unit out.

http://i1298.photobucket.com/albums/ag58/JeepHammer1/IMG_0244_zpsedcibkzh.jpg (http://s1298.photobucket.com/user/JeepHammer1/media/IMG_0244_zpsedcibkzh.jpg.html)

You WILL want a fan for the heat sinks on the annealing unit, good idea to get it in the voltage your power supply is putting out.
You WILL need a power supply that can keep up, anything under about 1,500 watts at rated voltage won't give you full output from the unit. (Don't get those stupid little LED light power sources).
Digital times are $5 all day long, that's no issue, just make sure it's in the voltage range of your power source.

----------

This is a link to 'Annie',
The Ferrite shown on the front of the machine isn't my favorite, but it's one size fits all...
https://fluxeon.com

This is a Ferrite with Litz wire, these come in a couple different gap sizes to better suit the case.
https://fluxeon.com/product/giraud-retrofit-coil/

It's a bit steep since Ferrite rings are between $2-$5 bucks on the surplus market and a $20 roll of Litz wire will last you a lifetime for this stuff...
Dirt simple if you want to experiment!

---------

Now that I know about annealing, I've not seen one single person do flame annealing correctly, that includes me.

If you see a (reputable) manufacturer flame anneal, you will see a long row of defused flames, cases moving (relatively) slowly past those defused flames.
This is lower temps, and longer duration.

I'm like everyone else, I used the oxygen engorged 'Jet' tip on the plumbers torch and WAY overheated the outside of the case. This leads to delamination of the brass grain structure.
I don't flame anneal at all, opting for open coil (defused) electro-magnetic annealing, or when I want it really precise, 'Hot Pot' annealing.

The cheapest way to accurately anneal is a lead smelting pot (Hot Pot) and glass, ceramic or steel shot blasting beads.
Small enough to easily get into the necks (and back out), and enough thermal mass you can do several cases at one time without lower the temprature of the pot.

You get accurate readings with a thermometer instead of thermocromatic paint, and the entire rig comes in under $100.

You will need a 'Paddle' with holes drilled in it for cases, metal or wood is fine...
Saves on burned knuckles (ask me how I know that...)

Some guys opt for salt, but I have an issue with a volatile corrosive liquid heated to the point it will melt skin, I screw up enough without adding to the danger level.

I opt for stainless steel shot, good thermal transfer, and no moisture issues.

With temp in the 730*F to 750*F range, it's just about a minute and you are done, nearly perfect anneal every time. If I were doing smaller volume, that would be all I'd do.

For electrical annealing, here is a video of cases being shoulder/neck annealed properly, notice the time factor in the coil, notice they never 'Glow', and notice the open coil they are going through...

https://m.youtube.com/watch?v=Ira3dmlclQ4&t=0s&list=PLlm0hjVAxYEN9EaOHweqc83Tp2thBN5Al&index=8

[vagrantviking]

I never cared for the molten salts idea either. Tried annealing in lead but the soldering issue of lead sticking to the cases was a pain.

Been getting pretty good success with the drill and torch but still difficult to get the level of control I would like.

Steel shot in a leadpot is a genius level of simplicity. Definitely going to try that.

Could you please explain the paddle you mentioned. Kinda hate cooking my fingers too.

[jpndave]

Nice writeup JeepHammer I'm going to look into those options. What size SS shot are you using?

[Grmps]

Great write up. would you please post links to:
This is a surplus 'China' unit, all the parts needed and a description on how to build this. Most of us don't have your depth of understanding in these matters
Ferrite rings
$20 roll of Litz wire
glass shot blasting beads.(please include preferred size)
ceramic shot blasting beads.(please include preferred size)
steel shot blasting beads.(please include preferred size)
Which of the blasting beads do you find works best

[country gent]

I use very fine glass making sand in a lyman lead pot. This is very fine sand and flows well. I have a rack made up that sits in the pot and sand under and around it. The rack holds 12 cases in the ring. this gives about a 15 sec soak time. I use a lead thermometer to set temp and a 40-50 min warm up time this allows the sand to fully heat and to get the 750* temp thru out the pot. I find the sand works better than steel shot since there are fewer air gaps in the media.