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Old January 19, 2017, 04:15 PM   #151
ShootistPRS
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Litz wire is often used in the power board but not for the heating coil. The copper tube is used because it has sufficient surface area and it can be cooled.You don't want to use the Litz wire for the heating coil unless you are heating from a flat coil where the coil can be mounted to a heat sink.
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Old January 20, 2017, 11:47 PM   #152
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Shootist,
I've been reading (always dangerous for me!) that Litz wire is often used on low duty cycle (Switched On/Off) units,
The guys using timers to limit the amount of energy the case gets.

The 'One At A Time' guys might benifit from Litz wire, I just don't know yet, haven't messed with it yet. Supposed to be here next week.

The full time (100% duty cycle) guys that use case drop to limit energy into the case would see the wire heating to probably unacceptable temperature and burning the insulation off between strands.

What I have on order is supposed to be 'High Temp' insulation, but didn't give specifics about insulation temp tolerances.
That's the pain with small batch buying, no manufacturers information, you are stuck with whatever the seller posts...
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Old February 5, 2017, 09:56 PM   #153
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Mr. Jeep hammer,
I have a few questions about annealing in general. First how far down the case towards the head is it safe to anneal to? If you were to pick a temperature at which you could safely say that no cartridge brass could be annealed below that temp what would it be. I was thinking 450 f. Basically I am using 750 and 700 tempilaq to make sure that I am hitting 700 degrees but not exceeding 750. But I am getting quite a bit of heat at the head. I want to put another tempilaq stripe on the parts of the case that must not be annealed just to make sure. Also have you had a chance to try the litz wire yet. As always thank you very much for letting me pick your brain.

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Old February 6, 2017, 04:14 PM   #154
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450*F is widely reguarded as 'Safe' for lower cases.

Keep in mind that there are folks that say dead soft cases are 'Dangerous', you should NEVER do anything that annealer the bottom of the case...

To this I usually reply,
"Have you Rockwell tested the bottom of factory civilian brass?"
There is always beating around the bush, quoting some arcane article written by an 'Outdoors' writer, then admission they haven't done any direct hardness testing at all...

Factory civilian cases usually come "1/4 Hard", Rockwell B scale of about 70-75, which is what most of the upper cases come in at,
And what most annealing is aiming towards.

As for being 'Unsafe', these same civilian brand new cases don't blow out in unsupported lower rifle chambers, like most semi-auto rifles have.
I'm positive in days past, when steel was questionable at best, a 'Hard', thick walled CASE helped support the chamber, no question about it...

Since most of the TENS OF THOUSANDS of steel alloys have been invented in the past 50 years or so,
And the forming of steel billets used to make barrels & recievers leave few voids, faults that can fail,
The older stories of 'Soft' cases leading to blown up firearms are in our past...

The case blanks, from 'Coins' being punched out of rolls of brass, all the way through the forming process, the brass is annealed AS A WHOLE several times.

The ONLY US manufacturer I'm aware of that produces 'Half Hard' lower cases is the US military production.
Since civilian cases don't have to stand up to machine gun links, get forced into machine gun chambers at a rate of up to 1,000 rounds a minute, rounds getting touched off or cook off before the bolt is in full locked battery, etc., I'm not as worried about lower case softening SLIGHTLY while I'm neck/shoulder annealing as some people are...
And I've never had a blow out, even when fired through machine guns.

When you heat to 'Dead Soft' (as in for forming the case for initial forming) you have to watch for overheating, both to keep alloy components from separating & to keep the brass from going 'Mono-Crystalline', removing the grain structure that allows brass to expand/contract without cracking.

You aren't getting close to that, so I don't see any big issues at all with hitting 700-750*F on the top end and keeping 450*F in the mid case.

With 700*F you aren't quite reaching the 'Full' annealing benifit, but you are annealing and if you are CONSISTANT with your cases they are seeing a very large benifit from annealing.
I'd rather do 700-730*F than overheat the cases,
So you are 5 Rockwell points off 'Optimum', big deal...
CONSISTANT is more important that the 'Perfect' Rockwell reading, and you have removed 80-85% of excessive 'Hardness' from the case at the same time!
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Old February 6, 2017, 04:22 PM   #155
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Update on 'Litz' wire,

A FAST electrical annealer that switches On/Off (timed unit) works outstanding!
Delivers considerably more power to the brass heating it faster, so you will have to watch/adjust your time.

Constantly On units (timing the case exposure to the coil), 'Litz' wire doesn't work at all.
The coil heats up and destroys the insulation between strands of wire.
Looking more like a cooled tube is going to be the only way to do this one.
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Old February 6, 2017, 05:09 PM   #156
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Litz wire is intended to have lower effective resistance than standard wire at high frequencies because it has a lower percentage of copper not carrying current due to skin effect. This raises the Q of coils, or else is used to reduce the wire diameter needed to achieve a given Q. However, that does not change the fact that heat is generated by running current through what resistance it has. And there you have the problem that the insulation around the individual strands interferes badly with their ability to pass heat to one another and out to the surface for air to carry it away. So, you may need smaller gauge litz wire for low resistance and hi Q in a low power coil, but in a high power coil, where heat dissipation is a factor, you have share the current out among a larger number of strands to avoid heat accumulation in the center.
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Old February 7, 2017, 11:04 AM   #157
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You lost me at 'Q'...
Please explain.

This is Very high frequency reversing polarity application.
The reason I tried Litz wire in the first place...
The eBay 'High Temp' insulation on the wire isn't what I'm used to for 'High Temp' applications, doesn't last long (and smells horrendous) when it's heated with continuously 'On' units.

Dropped annealing time on .308 cases a full second with switched power units, implying more power is being applied to the magnetic field and not wasted as Resistance in the conductor/unit.
Using Templiq time dropped to melt the paint from 4.3 seconds with the cheap China unit to 3.1 seconds with no other changes to the unit or power supply.

I'm aware of surface or skin effect with high frequency AC, but since I was working with DC power supply, the polarity flip (AC) didn't enter my addled brain until I read a Stanley Zinn article about frequency response difference between solid inductors & Litz wire conductors, and the light bulb above my head fizzled a dim light on things...

I understand the principals, I just don't have the education to canculate the 'Optimum' arrangement/materials.

Circuit design isn't my chosen field of study, so I'm researching possible materials & options that will work with these $50 induction units...



It's trial & error sometimes, but with collaboration it's SLOWLY making progress...

I put from 'Experts' is always welcome, but not always forthcoming... (hint!)

Last edited by JeepHammer; February 7, 2017 at 11:21 AM.
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Old February 7, 2017, 01:45 PM   #158
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When my unit turns on the magnetic field tries to kick the brass out of the ferrite core. I find that odd considering that my brass is presumably non-ferrous. Has anyone else had this happen?

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Old February 7, 2017, 02:41 PM   #159
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Sorry, double tap on slow server...
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Old February 7, 2017, 02:43 PM   #160
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Yes, I have observed the effect myself.
That's why I use a ceramic holder for the brass, and/or insulate the coils with fiberglass wrap.
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Old February 7, 2017, 03:26 PM   #161
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So the fiberglass wrap stopped that effect?

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Old February 7, 2017, 04:02 PM   #162
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What you are seeing is a reaction to the magnetic field due to eddy currents induced in the brass. Any conductor will do this. It's not a ferromagnetic phenomenon; just a magnetic one. JH is using ceramics (non-conductor) and/or fiberglass to keep the case in place. It doesn't stop the field from being there or from pushing.

An old fashioned demo used to be to make up a copper or aluminum disc and put radial slots in half of it, then mount it on a hand-cranked shaft oriented so the outer edge of the disc passed between the poles of a strong magnet. When you rotate the disc with the crank, it gets very hard to turn when the solid half of the disc is going between the PM poles, but suddenly gets much easier when the slotted part goes through. What is happening is the copper moving through the magnetic field induces eddy currents that have their own magnetic field that interacts with the permanent magnet to produce drag. Basically, it's a generator with a shorted output. But when the slots pass through they interrupt the eddy currents so they are much smaller and weaker and you don't feel much. But note that this works with aluminum or any other conductor, too, and is the principle the little magnetic damper on beam scales depends on to work.

In the case of the induction heater, you can look at the freqency of operation as the rotation rate of a virtual "disc" and the case as an unslotted disc. In this instance the eddy currents are of such magnitude that they make the brass hot. But they also have that induced magnetic field reacting against the field in the coil. BTW, you can put multiple ac magnets of opposing polarity, as you see with the poles of an induction motor stator, and tweak the phase (different start capacitances will do this in the motor stator) to cause the field reactions to either attract or repel a conductor. You could, in fact, make a brass magnet this way to pick up your brass. The problem is the power requirement is large for the amount of work it actually does.


Jeephammer,

The letter Q actually stands for "Quality". The electrical quality of an inductor has to do with how quickly it dissipates ac energy that is cycling through it at a given frequency. A coil that dissipates a lot of energy is said to be lossy or low quality for the application, and vice versa. Both inductive reactance and resistance are measured in ohms, but only the resistance dissipates any energy, so the Q of a coil is defined as its inductive reactance at the frequency you are finding Q for, divided by the resistance of the coil. The ohms cancel and you are left with a unitless ratio called Q or the Q Factor of the coil. As long as this is a high number, you can can take the ac volts times the ac current through the coil and divide by the Q to get close to how many watts are being dissipated in the coil itself. As Q gets lower, the phase shift between the reactance and the resistance, aka, the Power Factor, has to be factored into the calculation by multiplying voltage and current by the cosine of the phase angle between voltage and current. But we don't have to go there in this case. The bottom line is that you would ideally have a high Q coil for the induction heater so that it lost very little of the energy you put into operating the system. You would like the losses all to be in the brass, where the heat is needed. Physical reality just makes it hard to get there. Litz wire gives you high Q, but costs you the ability to easily get rid of whatever heat is still made.
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Old February 7, 2017, 06:05 PM   #163
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Unclenick is correct, I use ceramic to physically restrain the brass from moving,
While the fiberglass is heat resistant insulation to keep brass moving around from shorting out or changing resistance of the coil.

Fiberglass strips (pre made) guide brass into the ferrite on production feeder, keeping the brass from moving around too much and gets the necks into the ferrite without snagging.

On a side note, related but not directly applied to anealing,
What you are seeing is kind of the same principle a 'Rail Gun' works on.
Non-magnetic but electrically conductive between capacitively charged conductors.
A MUCH weaker version of the eddie current effect used on rail guns to get a non-magnetic projectile moving.
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Old March 13, 2017, 02:23 PM   #164
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DIY innealer (you build)

Hi guys...

Thought my may be interested in this youtube video. The link from the video will take you to www.accurateshooter.com and a thread on building this induction annealer. Parts and where to get them.
Works well (almost easy) to build. So far I know of, 10 that have been built and everyone likes theirs.. Cost is about $350-400.
Check it out

https://www.youtube.com/watch?v=57RL5v54FhM

Gina
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Old March 14, 2017, 09:19 AM   #165
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What I don't like about the video,
The case is being dropped into position with the timer running, so hesitation getting the case into place wastes time and case doesn't reach target temp.

Timer NEEDS to start when case is in place for consistancy so each case gets full annealing.

This is pretty easy to do from mechanical switch to proximity sensor.

This *Looks* like a continuously 'ON' coil unit, but I just can't tell from the video. It could be switched on/off by the timer, but that means the 'Off' time is tiny, it would have to be a pretty much 100% duty cycle induction unit.

Switched (On/Off) units NEED superior switching semi-conductors, which most of the 'China' units I deal with don't have. The switching gives up...
So normally, I cool the coil with water/alcohol mix & run continuous, doing like this guy and controlling the time the case stays in the coil.

One word of caution here, up around 1,000 or 1,200 watts & ferrite, particularly using Litz wire around the ferrite, you CAN seriously overheat the case neck, going well beyond 800*F pretty easily.

A slower 'Cook' will allow heat to creep further down the case, but will allow you to control the maximum heat applied to the neck/shoulder.
I'm still not knocking into the 450*F mark, just annealing creeping a little further down the case.

The open tubing coil helps with control, but again, it takes a little longer per case.
Ferrite REALLY focuses the magnetic field so you get a much more concentrated cook, and that is faster (time wise), but it's much easier to over cook the brass.

The smaller the coil, the closer the case is to the coil, and the faster the case reaches target temp. Rewinding the coil so it's tight to the case is more difficult with smaller tubing, but worth the effort...
Use fiberglass wrap to keep Case from contacting coils directly.
Fiberglass is electrical insulator, heat proof at these temps, and abrasion resistant so it lasts a good long time.
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Old March 14, 2017, 09:35 AM   #166
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I don't think so. The timer is on the left display and is behind the operator's arm most of the time, so it's a little hard to tell, but the coil is on only when the green LED above the work "annealing" turns on. That doesn't happen until the case is in place and on a second viewing you can see there is a pause during which the timer appears to count down briefly before turning on the power and counting up. So I think that countdown is the switch debounce and case settling time. In one run it doesn't trigger properly and the operator has to trigger it again. In the schematic you can see the green LED gets no power until the induction heater does.
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Old March 14, 2017, 01:09 PM   #167
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I believe you are right. I watched it again.
The timer runs, seems to be tracking down time before the case is dropped in.
The timer seems to reset when the brass is dropped into the socket.

Last edited by JeepHammer; March 14, 2017 at 01:14 PM.
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Old March 14, 2017, 02:52 PM   #168
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Took me awhile being slow on the uptake but I see what they are doing and why they labeled it "Auto Cycle". The annealing is a 5.4 second process and between annealing you have 3 seconds to load the next cartridge in. The counter increments to 3.0 seconds and the process starts. The process runs for 5.4 seconds, the annealed case drops and 3.0 seconds later the process repeats. Also noticed that they just turn the entire "Inductor PCB" On and OFF. That apparently works well as initially I was thinking about just gating the MOSFETS. Not really required, just turn the board On and Off using the contactor.

The 48 VDC supply powering the inductor pcb is showing about 43.1 VDC @ 12.2 Amps so they get about 526 watts. THe PCB Inductor Fan and the Radiator fan both run apparently on 120 VAC. I would likely use 12 VDC fans since the pump is 12 VDC. I don't know what the thinking was with the 120 VAC fans when 12 VDC home computer fans are inexpensive. Find a low cost CPU cooling radiator, pump and fan(s) and that should work. The 48 VDC 600 watt PSU won't be cheap, about $85 to $100 on Amazon. Using a cheap one shot timer would keep cost down. You just have to push a button for each cycle.

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Old March 15, 2017, 12:23 AM   #169
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Maybe this description of the timer may help...

The timing heart of this annealer is the Seatos digital quartic timer relay switch.
It is in fact 4 timers in one unit Timers A, B, C, and D. Timers A and C have SPDT relays controlled by the timers. In this annealer timer "A" is used to set up the amount of time a case is being annealed. it controls the 30 amp contactor/relay and the power (48 volts) going to the inducter annealing PCB.
Timer B, is not used and is set to "zero" time.
Timer "C" is usually set to .5 seconds and controls the trap door solenoid. Dropping the newly annealed case in the collector pan.
Timer "D" is usually set to 2.5 to 3.0 seconds. and is used for a delay to allow the operator time to insert another case into the annealing coil.
In recycle mode, this A, B, C, D runs continually. Annealing one case right after another. Remember timer D is a "delay" to allow the operator to insert another case on autocycle. The operator sets it up.

As far as 110 volt AC fans.. Yes 12 volt DC fans are cheaper.. But that is what I had on hand already, so I used them. Did not have to spend any more $$. And as I said in the tread.. GO for 12 volt fans !!

The whole idea of this annealer is a relativity low cost high volume induction annealer. There have been variatrions to this design since it was first published. Read the entire thread to see them
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Old March 15, 2017, 02:14 AM   #170
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For a guy wanting to anneal 100 at a time it's not too bad, pretty functional and fairly easy to operate.

Get beyond about a 100 cases at a time and auto feed comes in REAL handy!
Pyrex tube or ceramic end on the Dillon tube, and putting a Dillon case feeder on it wouldn't be difficult and would sure free some time up for other things...
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Old March 15, 2017, 08:58 AM   #171
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BTW... if you read through that thread, an auto-feed system has been designed for this annealer.
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Old March 15, 2017, 09:12 AM   #172
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Thanks for sharing the additional information on the timer used, much appreciated.

Ron
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Old March 15, 2017, 11:30 AM   #173
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your welcome... Glad to share.

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Old March 15, 2017, 11:50 AM   #174
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I'm glad to see that Rube Goldberg is alive and well !!
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Old March 16, 2017, 12:46 AM   #175
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Everything is 'Rube Goldburg' until someone works the kinks out and puts it into a slick case...
And marks the price up 1,000% and retails it!

'Open Source' just keeps the manufacturers honest & prices reasonable!

Drop through or belt feeding is as old as the industrial revolution,
Electrical Magnetic annealing is as old as semi-conductors that made it practical,
Nothing new or revloutional here, it's sorely needed for guys that anneal.
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