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Induction brass annealer redux

With the 750 power supply, and my current setup (8 turn coil w/ 1" ID), I anneal Hornady 6.5 Creedmoor cases in about 3.5 seconds, and Lapua 6.5 Creedmoor cases in about 6.5 seconds. In both cases, the amperage drawn increases over that time, starting around 11 amps and ending at 13 amps for Hornady, and ending at about 12.5 amps for Lapua.

I'm planning a couple mods, since I have current control working on my annealer, as well. I'm going to reposition my platform slightly to get the case deeper into the coil, and I'm going to wind a tighter coil (planning 8 turn, 3/4" ID). Those should allow the system to draw more amps, and shorten my anneal times a bit. I can then use current control to keep the times manageable (ie, not too short).
 
Hello everybody

I almost read everything (it is long) and I made my Ginaerick annealer. I have took Gina's original plan, with some modifications on the coil (more important diameter (1 » 1/8=28,575mm i have 30mm). But I have a problem with the 1/8" tube . It is very difficult to have a flow with my pump . I have this tube :

https://www.ebay.fr/itm/MAMOD-1-8-L...hash=item41dadd2f3d:m:m3QFzT7mdYX_fjuQBGJxn3w



But i think the inside diameter is too small (maybe several internal diameter exists?) . Have you any problems with you're ? A solution for me is to try a 4mm tubing (3/16" ) Thanks all for the plan, especialy Gina1, crocmax,fishindog, anri... and sorry for my bad english.:rolleyes:
 
Ok, I got my pump replaced - the new one shipped in a box instead of a padded envelope, and seems to be good to go. Time will tell.

I also built a 3/4" ID coil, to try to leverage a bit more of the power my supply can provide, if I could. It pulls more power unloaded (about 12A instead of 9.5), but immediately goes to the current limit I have set at 15.1A with a case in the coil. Interestingly, anneal times are basically the same for Hornady 6.5CM cases - about 2.5 seconds. But, Lapua 6.5CM cases anneal a full second faster, at 3.3 seconds, instead of the previous 4.5.

I don't know if I'll stick with the smaller coil or not, in the end - mainly, I was curious. I don't know enough about the physics involved to anticipate if it would cause any long term problems for the board. Still, I'm only pushing 720W, as is, which is 72% of the inductor board's rating, and I can build a longer pause into the cycle to give it a little more time to cool off, if need be.

If anyone has thoughts, I'm open to them :-) A coil swap isn't difficult, so changing back to the original 1" ID coil is easy.
 
Hi Dave...

I'm not really into the physics ether. The 1 1/8th ID coil was Hollywood's design. I know he did a LOT of experimenting to come up to that size. (for 308 case size) It works !! It is a known fact that the closer the case is to the coil, the more current you will pull. Hence your 3/4" coil will pull more current. Also one of the reasons for the 1/8" tubing for the coil is it is easy to form into the coil and not get any kinks. I tried 1/4 inch copper tubing, and never got past the 2nd winding without a kink..
As far as different brass manufacturers, I found that in some cases the annealing time is different, even for the same caliber case. Just the different brass formula.
Gina
 
I saw the picture of all the coils Hollywood made - some crazy experimentation, there!

I ended up annealing about 300 cases today (what had accumulated since my first pump started leaking). Everything worked fine, so far. The coil gets a little warmer than the 1 1/8", so I gave it a couple of short breaks to cool off. It never got past slightly warm to the touch, so not hot or anything. The capacitors remained cool to the touch (thank you, heat sinks and ample fan volume!). So, I'll probably roll with it this way for a while and see how it goes. If I ever get into anything larger (magnum case head), I'd have to go back to the bigger coil.

Not just brass formulation differences between brands, but also thicknesses, etc, too. Totally makes sense that they'd differ.
 
The induction field only penetrates brass .010" at the frequency I measured mine at, 110K Hz. The lower the freq the deeper the penetration in a given material.
 
GrocMax said:
The induction field only penetrates brass .010" at the frequency I measured mine at, 110K Hz. The lower the freq the deeper the penetration in a given material.
Click to expand...

Just my curiosity... What procedure did you use to be able to measure the temp at 1/100" depth inside the solid metal case ?
 
Gina1 said:
Just my curiosity... What procedure did you use to be able to measure the temp at 1/100" depth inside the solid metal case ?
Click to expand...

Didn't, the .010" depth for 110KHz and brass came from a chart in a white paper on induction heating, frequency vs. induction field penetration depth vs type of material.

For deep heating of iron based alloys the frequency is very low, like 50-100Hz.
 
OK...o_O Was wondering what kind of scientific equipment you had in your shop to do that kind of measurement. I'm lucky I have a table saw and a MIG welder. :)
 
Greetings

I am new to this this forum and I spent considerable amount of time reading and re-reading all 44 pages. I am really impressed with the ingenuity, knowledge and enthusiasm of the participants of this forum. As a retired electrical engineer and fellow long range shooter I got the bug to join the legacy of Gena and Erik.

Before I start the design/built process I need to clarify two details.
- Are there any tools for building the coil. I am sure that someone in this forum created a better mouse trap.
- It appears that the cooling components take considearble space and sometimes the user do not have timely warning for malfunctions. I wonder what would be the pros and cons of using connect/disconnect the annealing box to the house water and just "enjoying" the outflow going to the sink.
 
Thank you for the complements, we do have a great group here, and some really smart people too. :D

To build the coil is very simple, 3/4" PVC (schedule 40), 8 turns of 1/8" tubing, which is very easy to work with. So as far as I know, no one has needed special tools to make it.

There have been one or two builds, I know of, that are connected up to the household water supply. They work just fine.

As you can see from reading the full thread, this is everyone's build. How you want to change it, improve it, is up to you. What makes this a really good thread is the sharing of all the improvements and upgrades.

Good luck on your build.

Gina
 
I used a 3/4" deep well socket (attached to a ratchet, with the handle secured in my vise). Really, any tubular object with the right OD will work :-)
 
Hello
Just a little problem with my annealer. I try the machine with a varistor. And at the first time , he blow up. I think it's not the good varistor, and i have some difficuty with the choice (i'm not an "electronic guru"). My installation is on 220V. The varistor is a panasonic 240V 84J ERZV14D241. So if you have a solution , thanks a lot.
Ernest , bad Electronics engineer...:confused:
 
Hello ernest

You could have had a defective varistor.. :( Also check your wiring. At a rating of 240 volts it should have worked. If I may ask, "where do you get your parts"? Only reason I ask is for me to look over (on-line) what is available. Some times parts get mis-marked and you may have gotten a lower voltage varistor. This has happened to other builders, all different parts.

Gina
 
Gina1 said:
Hi Dave...

I'm not really into the physics ether. The 1 1/8th ID coil was Hollywood's design. I know he did a LOT of experimenting to come up to that size. (for 308 case size) It works !! It is a known fact that the closer the case is to the coil, the more current you will pull. Hence your 3/4" coil will pull more current. Also one of the reasons for the 1/8" tubing for the coil is it is easy to form into the coil and not get any kinks. I tried 1/4 inch copper tubing, and never got past the 2nd winding without a kink..
As far as different brass manufacturers, I found that in some cases the annealing time is different, even for the same caliber case. Just the different brass formula.
Gina
Click to expand...

I read somewhere that the way they bend tubes for music instruments is they first fill the straight tube with, I believe it was lead or tar? Need to look it up for correct details. They bend the tubing then remove the filler.
 
Webster said:
I read somewhere that the way they bend tubes for music instruments is they first fill the straight tube with, I believe it was lead or tar? Need to look it up for correct details. They bend the tubing then remove the filler.
Click to expand...

There's an alloy called "Cerrobend" that's intended for that purpose, and way safer than working with lead (or tar, for that matter, I'd imagine). It melts at a relatively low temperature (you use a double boiler type situation, and just boil water). http://www.csalloys.com/cerro-alloys-tube-bending-filler.html
 
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