Induction brass annealer redux

[Gina1]

Looks like you will be pulling air through your radiator, you make want to think about a removable air filter in front of it (the radiator) to keep dust and lint from clogging the radiator fins over time.
Same for the inductor PCB fan.

 

[Gina1]

Some thinking to think about

I heard back from one builder that was having problems getting enough flow through of coolant through the coil. It could have been a defective pump, maybe some sort of blockage in the plumbing, or the openings in the tubing was not reamed enough before assembly.
As the case maybe, I would recommend that before you put the whole thing together, you run a flow test through the coil / pump / radiator / tubing system.
I checked out my unit, and it ran about 100 mil liters per minute or a little less than ½ cup per minute. May save you some problems down the road. JMHO
Gina

 

[FishinDog]

Some thinking to think about

I heard back from one builder that was having problems getting enough flow through of coolant through the coil. It could have been a defective pump, maybe some sort of blockage in the plumbing, or the openings in the tubing was not reamed enough before assembly.
As the case maybe, I would recommend that before you put the whole thing together, you run a flow test through the coil / pump / radiator / tubing system.
I checked out my unit, and it ran about 100 mil liters per minute or a little less than ½ cup per minute. May save you some problems down the road. JMHO
Gina

Thanks for the heads up! Great idea; I'll run a test before I go too much further. I also checked fan direction and installed the filters. Thanks for all the tips! The filter over the PCB is just sitting there; not clipped in yet as I need access.

 

[GrocMax]

Not sure if this is helpful to anyone or not but here it is-

 

[GrocMax]

Here is the detail dwg of the sub board-

 

[Gina1]

WOW... From an acorn grows a mighty oak. Nice job.
Added constant current feature, auto feed, higher annealing current, and total case annealed counter. CrocMax, If I left any thing off, please add.

 

[GrocMax]

Optical start/stop switches, temp based PWM fan control.

 

[jimbo69]

Does anyone have any pointers on getting the pump rolling? I cannot get flow through the coil. Before soldering, I was able to blow air through it (albeit very little), same with post soldering (so I know solder isn't plugging it up). Any thoughts or pointers?

 

[GrocMax]

Its really easy to pinch off .0625" ID tubing bending it. For sharp 45's or 90's use a mandrel bender such as this- http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXE228

If you are positive no kinks, pinches, FO's or other obstructions are present, consider it takes a wee bit of pump head pressure to overcome the restriction of 3 feet of .062" ID STRAIGHT tubing. Add bends or surface roughness (scale) on the ID you add restriction. Test your pump with an open vertical clear tube and see how many feet it will pump vertical. If it is not making 3-4 PSIg worth of head it won't flow 100+cc/min thru the tubing. While the pump is rated at like 2 meters head (2.8PSIg) that doesn't mean yours is doing it.

Another option is to use thinner wall tubing. I'm stuck with 101 (pure electrical grade) copper which I could only readily get in .032" wall. 122 copper is available in .014" wall which will help coolant flow rate at low pressure differential.

Just the way we as individuals bend our coils, the tubing choice (.032" wall vs. .014" wall), and a pump or voltage on the low end can mean the difference between 'It works fine for me' to 'I don't have any flow'.

 

[bertn]

I have received most of the parts and have bend my coil but am wondering if one of you has done some experimenting with the flow direction of the coolant through the coil?

What would be best; flow from top to bottom of the coil or from the bottom to the top??

 

[kosmic]

I have received most of the parts and have bend my coil but am wondering if one of you has done some experimenting with the flow direction of the coolant through the coil?

What would be best; flow from top to bottom of the coil or from the bottom to the top??

I would say, from bottom to top to help in bleeding the system.

 

[Gina1]

+1

 

[FishinDog]

Assembly has begun! Box and front panels built but still waiting for 1/8 copper tubing to arrive. I checked the flow on my pump and it seems fine. I'll be anxious to see how much it's flow rate drops when going through the 1/8". In case you're interested, here's a pic of the flow direction to make sure you pull from the radiator and push into the bottom of the coil.

 

[Gina1]

Assembly has begun! Box and front panels built but still waiting for 1/8 copper tubing to arrive. I checked the flow on my pump and it seems fine. I'll be anxious to see how much it's flow rate drops when going through the 1/8". In case you're interested, here's a pic of the flow direction to make sure you pull from the radiator and push into the bottom of the coil.

View attachment 998684

Very nice... Great job on your front panel sub-assemblies.
Yes, flow rate will be greatly reduced once you start pumping it through the 1/8" tubing. On my unit, the output through the coil is 100 mml per minute or a little less than 1/2 a cup per minute. One really neat thing to do (once your unit is up and working) is hold the coil between your fingers, while it is running through a few cycles. You can feel the coil get warm/hot and then feel the coolant flow through the coil, cooling it.
One last tip, which I've mentioned before, be sure to ream out the tubing ends after you've cut them. Also dipping the coil into shellac will keep it looking bright and shinny. After almost 6 months, mine still looks like new copper. Hey, why do we run our brass through a tumbler.
Good luck and keep up the good work.

 

[FishinDog]

Very nice... Great job on your front panel sub-assemblies.
Yes, flow rate will be greatly reduced once you start pumping it through the 1/8" tubing. On my unit, the output through the coil is 100 mml per minute or a little less than 1/2 a cup per minute. One really neat thing to do (once your unit is up and working) is hold the coil between your fingers, while it is running through a few cycles. You can feel the coil get warm/hot and then feel the coolant flow through the coil, cooling it.
One last tip, which I've mentioned before, be sure to ream out the tubing ends after you've cut them. Also dipping the coil into shellac will keep it looking bright and shinny. After almost 6 months, mine still looks like new copper. Hey, why do we run our brass through a tumbler.
Good luck and keep up the good work.

Great pointers...thank you! I picked up some Shellac over the weekend. A little Flitz will make it nice & shiny before I coat it. Components mounted, now the wiring begins! Here's top & bottom pics. You can see the mini PLC I'm using on the right (covered with red "important" label) for controlling my hopper and staging release. As you can see it's a tight fit; I needed to put everything in a 14"W x 12H" deep space to fit on a shelf next to my reloading bench.

 

[Gina1]

Wow... What a lay out. Got small hands ?? Going to be tight wiring. Are you going to put vent holes in your case on either side of you 48 volt PS? I'm assuming it has a built in fan.
Trying to figure out were you radiator/fan is going in.
How ever you do it, it is a great lay out, very professional. I'll be waiting to see the finished project
Gina

 

[GrocMax]

I highly recommend buying a few glue on pin fin heat sinks to stick on the bottom of the induction board (ground plane) under the capacitors, it REALLY helps pull the heat away from them when you are running it full bore high duty. A heat pipe CPU sink salvaged from a PC would work really well if you have the room and can figure out a way to attach it.

On mine with no fan the heat sinks get H-O-T pretty quickly, with a fan they stay well under 100F.

 

[bertn]

Just to make sure everyone knows what we're talking about, must say that it has to be an electrolytic capacitor, so don't forget to place the right polarity in the right place.View attachment 992936

Hi Jose,

Could you (or someone else of course) give me some advice?

I don't have a 1000uf @63v capacitor so I am going to substitute it with
2 470uf @ 63v capacitors parallel for a total of 940uf. Hope this works.

My power supply to induction board is 40v switched by a 12vdc single pole automotive relay (40a)

Your drawing shows the relay switching the negative (black) wire, but I have my relay wired up to switch the positive (red) wire.
Will this also work with the capacitor(s) or do I need to re-wire the relay to the negative wire?

Many thanks!

 

[Gina1]

I highly recommend buying a few glue on pin fin heat sinks to stick on the bottom of the induction board (ground plane) under the capacitors, it REALLY helps pull the heat away from them when you are running it full bore high duty. A heat pipe CPU sink salvaged from a PC would work really well if you have the room and can figure out a way to attach it.

On mine with no fan the heat sinks get H-O-T pretty quickly, with a fan they stay well under 100F.

+1

 

[bertn]

I highly recommend buying a few glue on pin fin heat sinks to stick on the bottom of the induction board (ground plane) under the capacitors, it REALLY helps pull the heat away from them when you are running it full bore high duty. A heat pipe CPU sink salvaged from a PC would work really well if you have the room and can figure out a way to attach it.

On mine with no fan the heat sinks get H-O-T pretty quickly, with a fan they stay well under 100F.

What kind of glue would you use for this?