Induction brass annealer redux

[Dima Prok]

Voltage and Current adjustable power supply for $56 bucks, too bad it's only 10A, I have almost exact version without current control that came from ebay and it actually produces 11.5A and 51.7V https://www.banggood.com/Switching-...AkJUIgZGQlRfUEQoAQ&ID=514829&cur_warehouse=CN I ordered quite a few things from Banggood in the past most of was good experience. The best experience was getting a 4" chuck for mini lathe that holds under a thou runout that cost me 55-60 bucks. Worst experience ordering mosfets for uncle that looked to be desoldered from somewhere also wireless controllers 2/4 dead.

 

[Dima Prok]

3mm is closer to 1/8. Pay attention to the wall thickness of the tubing, very small ID (1.0mm) requires a pump with some oof-dah. You will need over 1 meter to make a coil with a long inlet/outlet run. Try to find 0.5mm wall or thinner 3mm OD 101 (pure) copper. 3.5mm will work too. 8 x 28mm x 3.1416 = ~700mm just for the coil windings.

I want to go with little bit larger OD and ID for better water flow. I think there is error in eBay description (I sent him message), he says the wall thickness is 0.5mm (.019") that should be 3mm ID and 4mm ID. I believe David101 used 4mm with success. I am not sure why Erick settled on 1/8" thickness my guess it's what was available to him at the time that was thinner than 1/4" even though there is 3/16 tube I see online. So at 70cm I will have plenty for 1 coil, it's 1 meter long, I was planning to make some kind of brass / copper blocks to clamp the coil and have larger connections on the other side to connect larger hose. I also though about rotating the position of the coil 90 degrees counterclockwise so the coil comes out the capacitor side and maybe even flipping them on the opposite side of PCB so the water is not flowing on top of PCB, it shouldn't be too hard to do.

EDIT: OK, just found Ericks old post apparently he settled on smaller tube because he couldn't wind 1/4 tube in to smaller diameter. If that's the only limitation than I believe this can be solved using salt/sand freezing water or low melting point metal.

 

[GrocMax]

0.5mm wall should be perfect. if you are going to do other things with it like brazing tube fittings etc. the 3.5mm would be my choice too. Hardened tubing you may need to anneal the tubing before bending. Molten salt, ice work good.

 

[270guy]

May be a silly question, but why do you have to change to the larger copper tubing, where it runs across and contacts the induction board? If the 1/8" coil was made with the ends long enough to go across the board (less joins), would that do the same thing? Or is the board set up to use the larger tubing? Sorry if this has already been covered. I realise I'll still need to get the 1/8" tube up to the right size to go through the pump and radiator, via plastic tubing.
cheers
Brendon

 

[SGK]

That plus larger ID copper (and tubing) poses less resistance to coolant flow.

(Post 1 describes use of and transition to 1/4" tubing. I routed only 3/8" ID tubing. I also made the transition simpler. I cut only a short, clamp width piece of the 1/4" tubing, slipped it over the 1/4"OD copper and placed the clamp right there rather than the two-sage process described there.)

 

[SandMoose]

So my build has started, or the purchasing aspect of it. I'm going with an arduino with an autofeeder attatchment. I'm using a power supply that has a load on load off logic level input, in lue of a SSR.
Questions
1, why has nobody thought to just use a copper coil inside a bucket of icewater for cooling? seems that with the restricted flow you would want the coldest coolant possible and it eliminates a fan etc..
2, i'm using earthmake.com's integrated touchscreen arduino combo which in the future I plan on upgrading to a larger LCD that will display joules etc, any thoughts?
3, what if any input would you have regarding using the adjustable platforms with dual steppers for height control? I really like the adjustability of it but the complexity seems a bit much for the gain,,, Thoughts???

 

[270guy]

So my build has started, or the purchasing aspect of it. I'm going with an arduino with an autofeeder attatchment. I'm using a power supply that has a load on load off logic level input, in lue of a SSR.
Questions
1, why has nobody thought to just use a copper coil inside a bucket of icewater for cooling? seems that with the restricted flow you would want the coldest coolant possible and it eliminates a fan etc..
2, i'm using earthmake.com's integrated touchscreen arduino combo which in the future I plan on upgrading to a larger LCD that will display joules etc, any thoughts?
3, what if any input would you have regarding using the adjustable platforms with dual steppers for height control? I really like the adjustability of it but the complexity seems a bit much for the gain,,, Thoughts???

I can't comment on 2 and 3, as that just seems to complicated for myself. I have two calibers to anneal for, so simple is great. On 1, here is why the radiator / fan / coolant combo works for me (I'm just starting the build). When it built, I want a unit that can be put on a shelf or any where to store it, then bring it out, plug it in and turn it on, away you go annealing. When finished my annealer, should hopefully be reasonably compact. I don't want to get a bucket, get some ice, add some water,do my annealing, empty out the bucket. Not saying that it isn't a good idea, just not for me.

 

[SGK]

3 - all good fun if you are into that sort of thing but just remember it takes less than a couple of seconds to adjust a shelf height manually. A stepper controlled shelf would only really be advantageous if shelf heights for each caliber were stored and easily recalled (along with annealing times)

 

[David101]

I would have chimed in earlier but hadn't seen the thread come alive again.

The larger diameter coil really worked well for me. It allowed more water to flow which also helps flush out any air bubbles. I did have a problem with a SSR so have a backup plan. Put a reverse diode everywhere as in the schematic ie on input to induction board, Relay or SSR and Solenoid. I found this also stopped a slight blank display like a glitch in the voltmeter.
The Flux concentration model I think has its place for certain cartridges. I think I like the work coil better. Still trying to get a real good handle on the temperature / time equation. Also equating that with no indication in heating colour changes (turning red or pink) but still getting a change of the case colour like a factory Lapua.

There is a lot more heat generated in the layers of the PCB than I think other have previously realized. This becomes more evident when you eliminate the other sources of heat like the work coil. The water through the coil as in the basic design is plenty even better with a slightly larger tube. I have tried using capacitors standing off the board as much as possible and capacitors across the output on top of the work coil they dont really get anywhere near as hot as the PCB itself.

The heat sinks on the bottom of the board really address the heat generated in the PCB Layers. I have also added some extra external wire from power supply through the mosfets to share some current in the PCB.

All this is great if you are into electronics otherwise the basic design is very solid. Just QA your induction board before use.

 

[GrocMax]

Capacitors generate a large amount of heat in this application, the heat travels thru the large axial leads into the board, predominately into the ground plane of the circuit board, the heat sinks become quite effective.

 

[SandMoose]

So, in starting my build ive noticed a few things about the induction board.
first, they are desgined to operate at 45m hertz... but when you shrink the coil by a lot which we are doing the resonance increases to around 100 which more than doubles heat loses etc which is why the board is getting hot, parasitics are a pain and this board is full of them.
I am continuing to collect parts, but I wonder if there is an interest out there to build a propper board with proper materials??? anyone???

 

[Dima Prok]

I found about 3 feet of 3/16 copper tube that I got from recycle place previously. I am about to wind it by first trapping some water, I also have some fine white sand I brought home while vacationing For those of you who used fiber sleeve, did you put it on before forming coil or after? Also with increased diameter should I stay with 8 turns or perhaps go down to 7? I am planning to anneal 223 and others based on it.

 

[hambone1971]

I found about 3 feet of 3/16 copper tube that I got from recycle place previously. I am about to wind it by first trapping some water, I also have some fine white sand I brought home while vacationing For those of you who used fiber sleeve, did you put it on before forming coil or after? Also with increased diameter should I stay with 8 turns or perhaps go down to 7? I am planning to anneal 223 and others based on it.

Put the sleeve on when the copper is straight then wind it over some PVC or whatever. Keep with the plans on size and number of turns as best you can. I didn't use any loading of anything in copper and it wound just fine just go slow. The sleeve will prevent coil shorts and brass shorting the coil in operation and it looks nice. These coils aren't critical as they run around 80 to 100 Khz frequency it seems. Good luck..HB

 

[GrocMax]

Clear lacquer paint is all you need to keep shorts from happening.

 

[Gina1]

Clear lacquer paint is all you need to keep shorts from happening.

KISS.. A yup.

 

[Dima Prok]

Put the sleeve on when the copper is straight then wind it over some PVC or whatever. Keep with the plans on size and number of turns as best you can. I didn't use any loading of anything in copper and it wound just fine just go slow. The sleeve will prevent coil shorts and brass shorting the coil in operation and it looks nice. These coils aren't critical as they run around 80 to 100 Khz frequency it seems. Good luck..HB

Hambone, original plans were designed on 308 case, I will be doing smaller 223 based cartridges, if I can optimize it why not? I am using 3/16 tubing, because that's what I got. Without having to order 50ft of 1/8" tubing on eBay and paying $35 I'll save some $$ but mainly because with larger ID diameter I will get better flow, better heat transfer, less pump stress.

The reason I am preloading is for coil to not to kink during bending as was happening to Hollywood if you read his old threads I found when GinaErick project was at its infancy it appears the 1/8" size was chosen solely based on fact that it could be bent easily, if that's true this kinking can be easily avoided and that also means I can flare it easier too and avoid soldering, to me this is more KISS

P.S. Found this flaring tool that I can make on my lathe in 5 minutes https://www.lowes.com/pd/LENOX-Flaring-Tool/1000668265

 

[GrocMax]

With the 101 pure copper tube I used (because it is slightly more 'efficient') I couldn't find thinwall at a decent price, so bend radius pinch can be an issue. With thinwall 12x tube it really isn't necessary to use a filler. Half hard tube will bend without collapsing easier than fully annealed tube, just use a cheap bending tool available at your local hobby shop or on the net-

https://www.towerhobbies.com/cgi-bi...MIr5Sar6rV4QIVzZyzCh0DYA5xEAQYAiABEgJmTfD_BwE

You can make some pretty tight radius bends with this, it do take some practice though.

Square or D profile tube is supposed to even more efficient, I've wanted to make a press die for turning round to square for quite awhile now. It ain't difficult, but you'd need to fill it during the bending process, because that WILL kink or collapse.

 

[hambone1971]

Hambone, original plans were designed on 308 case, I will be doing smaller 223 based cartridges, if I can optimize it why not? I am using 3/16 tubing, because that's what I got. Without having to order 50ft of 1/8" tubing on eBay and paying $35 I'll save some $$ but mainly because with larger ID diameter I will get better flow, better heat transfer, less pump stress.

The reason I am preloading is for coil to not to kink during bending as was happening to Hollywood if you read his old threads I found when GinaErick project was at its infancy it appears the 1/8" size was chosen solely based on fact that it could be bent easily, if that's true this kinking can be easily avoided and that also means I can flare it easier too and avoid soldering, to me this is more KISS

P.S. Found this flaring tool that I can make on my lathe in 5 minutes https://www.lowes.com/pd/LENOX-Flaring-Tool/1000668265

Not knocking anything your doing maybe it came across wrong. I've used the 4mm x 3mm thin wall on Ebay for my coils and better water flow. Just didn't need to fill it with any stiffing agent to wind on form. It wound just fine being thin wall tubing no kinks. Got better flow and cooling. All this is a big fun experiment and we are all learning from each other. On the original 1/8 tubing it does help to run a .066 drill in each end after cutting the tubing to open it back up for better water flow before any bending as the cutter chokes it down a lot. Happy Experimenting and Good luck ... HB

 

[Brucey Boy]

With the 101 pure copper tube I used (because it is slightly more 'efficient') I couldn't find thinwall at a decent price, so bend radius pinch can be an issue. With thinwall 12x tube it really isn't necessary to use a filler. Half hard tube will bend without collapsing easier than fully annealed tube, just use a cheap bending tool available at your local hobby shop or on the net-

https://www.towerhobbies.com/cgi-bi...MIr5Sar6rV4QIVzZyzCh0DYA5xEAQYAiABEgJmTfD_BwE

You can make some pretty tight radius bends with this, it do take some practice though.

Square or D profile tube is supposed to even more efficient, I've wanted to make a press die for turning round to square for quite awhile now. It ain't difficult, but you'd need to fill it during the bending process, because that WILL kink or collapse.

I used a broom handle to wind the copper tubing around. Put the handle, or a piece cut off the end of the handle, very firmly in a vice so you can put plenty of tension on it and you can control the spacing between coils at the same time.

 

[GrocMax]

I used a broom handle to wind the copper tubing around. Put the handle, or a piece cut off the end of the handle, very firmly in a vice so you can put plenty of tension on it and you can control the spacing between coils at the same time.

The actual coil winding is not the issue, its the sharp radius bends you may need to make sure the rest of the deal has no extra areas where induction can occur.. Most industrial coils are single loop, if the coil runs are parallel make sure nothing conductive comes in between it, or induction IS happening at that point. So say if your setup uses a metal case, don't run the coil leads thru individual holes, use a larger slot so there's no metal in between.

Somewhere many pages back on this thread I posted some links to industrial coil design everybody who wishes to experiment with coil design should read, it has all the basic do's and don't s, what a cancelling loop is and how to use it to improve the design, etc. These are not highly technical articles, easy read with examples.