DIY Electrical Annealing Of Rifle Cases

Using a power strip for switching,
A 24 volt DC power supply,
The $35 induction unit and $4 worth of fiberglass tubing...

Barrel steel starts at room temp, 68°F.
Power strip turned on for 15 seconds, 15 seconds of direct induction heating,
Barrel stump at 210°F.

IMG_0255_zpspjlysgx5.jpg


Now, me switching the power strip on/off by hand, using the second hand on my watch isn't necessarily the most accurate way to do things, but you get the idea...

IF YOU ARE GOING TO USE A 'SLUG' TO KEEP CONSTANT TEMP, YOU MUST RUN A COOLING SYSTEM ON THE COILS!

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Now, I've NOT got a good way to get the brass out of the ceramic insert and temp check it without burning myself, pliers required...
So the case gets a few seconds to cool down before I get a temp reading.

IMG_0257_zpssyfipwfd.jpg


Starting at 68°F. with 24 Volts DC powering the coil,
And remember, if the coil were smaller, it would heat much faster...
I wound up with a case temp reading of 488°F in 20 Seconds.

EDIT: 748°F at 46 seconds on 24 VDC.
Much faster if voltage is bumped up or if coils were smaller, about 1/3 larger than the case itself.
I still need to adjust the case for depth in the coils, getting annealing further down the sides than I like, but I'm not drilling holes in my table top for a demonstration...
 
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In the spirit of NEVER leaving anything alone,
I used a piece of 10 GA. solid copper wire instead of the tubing,
Reducing the coil diameter to just outside of the ceramic insert (MIG welder gas cone),

The time didn't change too much, came in about 28 seconds, still using 24 volts DC,
But the results were MUCH better since I turned the coil sideways to control the depth the ceramic insert/stop allowed the case to enter the coils.

IMG_02601_zpstchsjtrc.jpg


Don't know if you can see the annealing color change on the neck of the case, laying on the table, but this REALLY worked out for getting the annealing where I wanted it.

With solid copper, you MUST switch the induction unit On/Off between cases to allow the coil to cool.
Left on continuously it would eventually melt the copper coils.

This is no issue at all for the guy wanting to anneal one case at a time, no automatic feeding system.


The next step is to find some copper tubing I can reduce coil size but still run cooling water through...
Maybe 1/8" tubing, just larger than a 10 Ga. wire...
 
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When I find smaller tubing I can make smaller coils out of I'll post that up when I have time.

As timers come in, I'll post up pictures of that process also,
*IF* anyone is still interested at that point...
 
Mr. Guffey,
I know there was some info in that somewhere, probably about using a case way too often, but I couldn't decipher the point you were trying to get across.

If it was about using a case way too often, then I agree.
The brass migrates forward, becomes brittle and uneven, and won't hold it's shape.

While bench shooting, and just plugging around out here in the woods, I've found that annealing, especially after one or two firings, brings the case back so it can be used accurately (as accurate as any fired case can be brought back) for another 2 or three loadings and still be accurate.

Somewhere around 7 to 10 loadings, the way I do things the neck won't hold the bullet with consistent tension, then it gets a crimp and becomes 'Blasting' ammo, which the cases are 'Junk Brass' after that last firing.

I'm not a molecular genius, I have no way to test the brass each and every time it's used, I do use a very precise pull gauge to figure out when neck tension gives up (simply because it's available at work).
At somewhere between 7 & 10 firings I simply can't get the neck to hold the bullet with the pull force that works best for me, so that's my limit on reloading the brass WITHOUT a crimp.

They work fine for the crimped rounds I let the friends, nieces/nephews, ect. blaze away at my target posts with for that last firing,
Then they are finished...
(Still yellow brass and worth something, if just scrap weight)

The other end of this is,
When properly annealed, even once fired military machine gun brass comes back when good dies are used,
Which saves a TON of money when I'm rolling 'Field' loads, varmints, hunting, general shooting off anything but the bench rest,
And they turn out pretty darned accurate, shooting dime size 10 shot groups, only slightly larger than my 'Virgin' cases through a bench rifle.
 
Bill DeShivs
Senior Member

Join Date: April 7, 2006
Posts: 8,151 Me, too.
I'm learning that you guys WAY over-think case annealing.....
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__________________


James K
Staff

Join Date: March 17, 1999
Posts: 22,852 I am not sure I understand how the case is kept from being over-annealed, or softened all the way down instead of just at the neck area where we normally anneal work hardened cases.

Jim
Click to expand...
__________________


1100 tac
Senior Member

Join Date: February 7, 2012
Posts: 188 Yeah,,I like to do a lot of thinking when I'm dealing with 50kpsi...
Click to expand...


Mr. Guffey,
I know there was some info in that somewhere, probably about using a case way too often, but I couldn't decipher the point you were trying to get across.

If it was about using a case way too often, then I agree.
The brass migrates forward, becomes brittle and uneven, and won't hold its shape.
Click to expand...

Thank you, all of the annealing threads on all forums can be superimposed on top of each other and end up with the same results.

Bill Deshivs suggested there could be some over ‘way’ over thinking going on. I suggest there are rules and I suggested factors should be considered

James K. expressed a concern; rules and factors would address his curiosity. I understand gigs of space have been used proclaiming the use of Template sticks, in the beginning it was not designed to be a habit.

James K. wants to know how heat can be directed to one area of the case and prevented from traveling to another. I made an annealing machine, my annealing machine addresses that issue.

F. Guffey
 
I'm a dim bulb sometimes about things, but I'm bright enough to at least listen to the experts when they try to give me advise!
Click to expand...
It's simply heating a small portion of a brass case.
It's not high tech rocket science, and doesn't require high tech equipment

I thought you had your annealer up and running "1500 pieces per hour" back in the middle of December last year, but here you say you're waiting for parts to build one?
 
Snyper,
I have a 6 piece automated annealer, MUCH larger power supply, up and running.
I'm pretty sure no one here wants to pump $3,000 into a production annealer just to find out *IF* annealing helps them or not...

This is working with 'Off The Shelf' components on the surplus market.
This round of small annealers are for guys wanting to do it themselves and don't care about production speed...

If you read the thread, I was asked to post up pictures of the smaller units as the parts come in, that's what I did.
They asked for it, they got it reduced to the most simple terms and common components I can come up with.
Someone else might have a better idea of how to reduce costs or increase reliability, this is just what I've come up with through experimentation.

---

As for what part of the case gets annealed, everything I've seen from the factory processes run the case TOP through the annealing coil,
They don't make any effort to keep the heat from transferring to the lower case.

I anneal so the brass forms to the bullet, giving a specific neck tension, grip on the bullet, and it seems to prolong the life of the case in the process.

It would seem to me if you wanted to keep heat transfer away from the lower case, it would be as simple as a water bath,
But I don't believe I would want that thermal hard/soft line in the case to potentially create a separation line.
I would very much like to know what Mr. Guffy came up with, what he found out since I'm annealing, but it seems he's not giving any details of what he built or found out....

It's like anything else, There are people that won't want to anneal,
There are those that will gas anneal,
There are those that won't know the difference,
And there are those that will do what I do, electrical anneal.

All of the above are OK with me, to each his own.
I find annealing a valuable tool, so I do it.
 
Are you saying that after a couple of annealing's the case does not snap back and you need to toss it at about the 10th use?



Does it flip a DC field or is the A/C doing the job in the coil?
 
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As for what part of the case gets annealed, everything I've seen from the factory processes run the case TOP through the annealing coil,
They don't make any effort to keep the heat from transferring to the lower case.
Click to expand...
They don't need to worry any more than those who use any other method, since if you heat the neck quickly enough, there will be little transfer to lower portions. You can see on new brass the color changes on the necks alone.
 
RC20,
It depends on the composition of the case.
Some will do more reloadings than others, and since I don't have equipment to tell precise components in the brass, or precise amounts, I can't tell which cases will 'Come Back' better than others in advance.

Annealing a little 'Slower' (lower power, longer exposure time) seems to produce consistant neck tension longer, but those cases show 'Migration', thinning of the brass in the case wall worse than fast annealed cases.

My military brass annealed the first time slower/lower power, then annealed with the rest of 'Production' brass last longer without the usual neck splitting that I had issues with when using military brass, which using Rockwell hardness scale testing, show up 'Harder' than civilian brass much of the time.

My THEORY is unproven by close scientific testing,
but goes like this...
Military cases are hard crimped, a through annealing takes the work hardening out of the neck, and returns the brass back to 'Dead Soft',
So the stress/work hardening is removed, and the brass simply lives longer without splitting.

I'm also sure NOT being shot in a sloppy machine gun chamber helps the brass live longer,
But between hard crimps, and sloppy machine gun chambers, military brass has had a hard life before it gets to me,
I'm also sure using a 'tight' chamber limits the work hardening and blow out problems to some degree once I get it.

As for AC or DC, that's a 'gray' area to guys that work with electronics.

House current doesn't 'Flip' polarity nearly fast enough to do this process out of a wall outlet, and the house current can't be 'Switched' fast enough, so its not compatible with the switching electronics.

A 'Flat' DC input is required for the 'Switching' circuits, so they can deliver current (amperage) polarity 'Flips' with no 'Ramp Up' time to full power.

This is the 'Electro-Magnetic Link' in action...

Every MOVING electrical current produces a magnetic field.
The key here is MOVING.

Every MOVING magnetic field passing through an electrical conductor produces an electrical current.

This is called 'Induction', Meaning to 'Induce'.

MOVING electrical currents and magnetic fields are interlinked by the laws of physics, they can't be separated.

By alternating polarity (Flipping) from a DC source, the unit produces AC at a VERY high frequency, And at a very high power.

This pulls electrically conductive materials 'Back & Forth' creating friction on a molecular level, which heats the material all the way through, all at the same time.

As Voltage switches polarity at full power, the magnetic fields produce 'Eddie Currents' as the magnetic poles reverse, which 'Excites' anything electrically conductive in close proximity.
That 'Excite' shows up as 'Heat' energy from friction.

The higher power the switching semi-conductors can handle, the more powerful the induction effect.
Most semi-conductors can't deal with an AC input, so you simply use a DC input to the induction unit.
This isn't much different than any other compound electrical device, from TVs to microwaves, ect.
Home power AC is converted to DC then used for the advanced electronics.
Virtually every electrical device other than incandecent bulbs and simple motors use a 'Rectifier' to convert AC into DC, so it's not 'New' or 'Rocket Science'...
 
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Snyper,
What you see on the case as a 'Line' is a reaction with oxygen at a given temp.
Cases annealed in an argon gas shield do not show the 'Line'.

A 'Shiny' upper case neck is almost always a case that has been overheated, bringing the Zinc to the surface, which is easy to test for with chemical reaction, something that reacts with zinc strongly that doesn't react as quickly with copper/brass.
Separate the zinc and you don't have 'High' brass anymore, you have more copper than zinc and you are on the path to a neck separation, especially at the top shoulder bend.

How you do things is entirely up to you. If it's working for you, you are doing something correctly...

It simply makes more sense that INTERNAL heating the case through induction gets you a more even heat,
While EXTERNAL heat sources produce excessive outside heat, waiting for the heat to transfer ('creep') through to the internal part of the case,
While in some cases, the outside of the case seriously overheats...

It's one of those things that 'Seem' simple, but is actually complex...

If what you are doing works for you, then by all means keep doing it.
Just keep in mind this is a thread on electrical induction heating, specifically a 'How To' thread,...
 
RC20,
The more electrical resistive (Resistor) the material (like steel opposed to copper) the faster the material will heat up.

Since brass has a lot of copper, its slow to heat.
I use a much higher powered supply than would be nessary for steel, with more robust switching (and larger heat sinks to keep those semi-conductors cool) in production.

Its not nessary if you are running lower power.
One 'Trick' is to turn the power supply fan so it draws air over the heat sink fins of the induction unit.
Might as well use the fan to do two functions at the same time aince the two components are in close proximity to each other.

This isn't 'Rocket Science', its actually pretty simple when you break it down into component pieces, and the components are dirt cheap, often salvage parts,
Got any idea how many microwaves, TVs, computers, ect get scrapped every year in this country?

Microwave turn table motors work VERY well for case feeder power units.
A 5 gallon bucket, turntable motor, piece of plexi-glass from the hardware store and a couple of switches and you are off to the races with a case feeder that would normally cost $250...

Bullet feeders are a little more tricky to figure out, but mostly the same cost to build, and they often run closer to $500

Tread mills are everywhere, they will supply you with everything but sealed container, and they make INDUSTRAL grade brass tumblers.

Just a little 'Hacking' of other common crap, like 'Plasma' TV sets will often net you the high powered switching semi-conductors needed for high powered annealing, along with things like transformers, ect.

Some guys have no idea how electricity works, so anything beyond changing flashlight batteries is going to baffle & scare them...
The 'YouTube' DIY videos on induction heating will show a ton of components, how to wire them, tips on soldering things together, ect when you start out.
With directions like that, if you can put a model car together you can build the annealing unit from scratch/loose parts...
 
JH:

I work with generators, switchgear, motor controls, UPS, building control systems. I just spend a good part of the last week on a 5 gallon bucket working on a simple air conditioning unit that defied others (and won).

I think it takes more than electrical knowledge, its takes what I think of as an artist imagination to do what you are doing.

My hat is off to you. I have done some pretty good circuit work to get a system to do what I wanted but pulling all that stuff together to do what you have done is beyond me. I can understand it if I see the diagram, and might even be able to add to it, but doing it from zero no.
 
I'm not working from nothing, there is about 250 years of electrical experimentation before me...
It takes rooms full of electrical engineers 10 years to work out something like a common ignition module, but once it works and is dependable, you can use it for a TON of stuff.

I have a lifetime of 'Rube Goldberg' gadgets behind me, and some still ahead of me, if I'm lucky! (knock wood)

Case feeders aren't exactly 'Precision', the most precise tool I used was a tape measurer, and nothing like saving $230 to keep you motivated!

Same with a lot of the stuff we use, I'm using a cement mixer to clean volumes of brass, cheap, turns the right speed, handles heavy weight, dumps easily, line the drum with HDPE sheet (the same stuff used for flexable cutting boards in kitchens) and you are off to the races.

Case annealing is one of those things,
Flame annealing didn't do the job I wanted, so I looked into how the big places do it, scaled electrical annealing down to what I needed.
Looks goofy, but it works for my application.
 
Annealer

Jeephammer i need some help with the "one at a time" method..i bought the induction kit in your link..and cant get it to heat fast enough to only heat the case mouth..it is very long, how many seconds it is supposed to take for a 308 brass with this little 150watt inductor
 
You can calculate what it would take. You have something like a gram to a gram and a half of brass in the neck and shoulder. The specific heat is about 3/8 of a joule. So, to raise the brass about 400°C would take about 150 joules. The definition of a watt is a joule per second, so if you got 150 watts to transfer without loss to the neck and shoulder, it should be done in about a second. In reality, you are using an air core coil, so it might take three seconds, but not long if all is correctly in place.
 
It's the 150 watt thing.
Normally I start at 1,000 to 1,500 watts.
Go much above 1,500 and watts and you start looking at 220v power supply to feed it.

150 watts just isn't enough to feed the beast.

What input is your induction unit rated for?
Maybe just use a bigger power supply?

You might also look into a ferrite 'C' core to 'focus' the smaller output unit.
Are you willing to work with this some? If so, I'll try to walk you through debugging it...
 
I may actually build one of these. Now, I may complicate it a bit. Would it be plausible to add a photo gate and have the brass free fall through the coil and use the gate as a delay timer to let the brass free fall through and anneal only the neck? Or maybe just as a way to let the more volume geared machines cycle on and off
 
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