Induction Work Coils for Brass Cartridge Annealers - Part 2: Manufacture

Making an induction work coil using 1/4" copper tubing. I use regular table salt to prevent the tubing from crushing, then push the salt out with water. See the previous video for the design parameters:
===Timestamps===
00:00 Introduction
4:45 Cutting and filling the tubing
8:51 Coil winding
12:19 Measurement
18:58 Removing the salt
22:37 Conclusion

[@DireWolfForge]

I appreciate your videos. Thank you for testing all of this out.

[@frenchcreekvalley]

Good job! -You might tell folks WHY there's an upper limit on frequency. If you are using the Chinese 1000 watt ZVS induction heater that is so popular, the higher the frequency, the higher the likelyhood of the circuit failing because the Mosfets spend too much time in the linear mode, creating a LOT of heat. Personally, I don't recommend going much over 100 kHertz with those heaters if you plan to run them hard.

[@Smithermal]

very good video, loves

[@AntonioMoraesBR]

Thanks a lot!

[@ajdavies]

Very cool video series on your annealer build. I assume you ended up sticking with 10x 0.33uF capacitors?

[@TechDregs]

Yes, from what I remember, those were easy to find in higher frequency versions without doing special orders. Other values were less common.

[@lauriemattila5936]

If inductance is used to melt aluminium in a crucible is there a preferred frequency. Also cast iron. Thanks great video slow an easy to follow.

[@TechDregs]

Depends on the size of the piece, really. Thicker parts use lower frequencies. But melting large chunks of aluminum or cast iron would take a lot of power. See pages 63-64 from references to skin depth and frequency for different materials.

[@greenbudkelly2820]

Good video but I have a couple questions Why use tubing rather than solid wire? #6 is readily available by the foot everywhere and just under 3/16” diameter. What brass are you annealing that you need a coil that big?

[@TechDregs]

Heat. You need to water cool the coil, or it will get very hot due to the brass radiating and resistive heating.

[@whateman12408]

Try vibrating coil with Electric toothbrush/massager etc to remove sand with water or air.

[@Von_Hohenheim]

id put rock salt into it and shake it as you allow it through the loop by spinning and using gravity to get it the whole way to the other end then flush with water for any salt residue

[@Breakcontact2]

I'm waiting on an ammeter in the mail still, but does the increase or decrease of the inductance raise or lower the current draw of one of the commonly available induction heater boards?

[@TechDregs]

Lower inductance will tend to increase current. Lower inductance gets closer and closer to just being a straight wire short.

[@georgewilson60]

I wonder how sugar instead of salt would work, then you could warm up the coil and flush with hot water to clear the tubing....

[@TechDregs]

Might be worth a shot if that's what someone has to work with.

[@windworldwide8840]

Hi ! ... is it possible to have the coil away from the zvs ? with a handle ? .... electrical wire between the zvs and the coil ?

[@TechDregs]

Yeah. You'd want to use heavy gauge Litz wire (or at minimum fine stranded wire) for the leads. Depends on what you are going to use it for, honestly. They sell induction bolt heaters that are pretty portable that might be easier to use.

[@windworldwide8840]

@@TechDregs 😁 Thks ! ... i will receive mine next month, ... with a small crucible, ... but i don't have enough hands to manipulate all parts, moulds, ect ! 🤣

[@windworldwide8840]

@@TechDregs i would use 1 meter 4mm2 audio wire from the zvs to the coil tube ... with cooling. do you have any advice ?

[@TechDregs]

@@windworldwide8840 All depends on how much power you're running through it. It might work fine, but I definitely wouldn't go any smaller than that. Keep an eye on the temps, and if it's not getting hot, then it's fine.

[@malchish-plokhish]

Hi! What coolant did you use? Distilled water or some kind of antifreeze?

[@TechDregs]

It's just PC coolant.

[@AntonioMoraesBR]

will that coil work with aliexpress 1000W ZVS? I think we should be on 1.25uH according to specs. Thanks in Advance!

[@TechDregs]

Please see the previous video on how to design/specify a coil for a particular circuit. It goes into all those details.

[@AntonioMoraesBR]

@@TechDregs thanks

[@OE8ACT]

@@TechDregs Thank you very much for the video. Just wounded a dual layer coil for my ZVS (1000W). I used a 4mm OD copper tube (diameter including isolation 4.6mm) and a pipe with 25.4mm diameter. I have choosen 4 turns by two because the measured inductance of the original coil delivered with my ZVS (1000W) was about 1.8uH. On my board there are five 0.33uF Capacitors in parallel. The tip with table salt is awesome and winding was much much easier than thought. Took me not longer than 10 minutes. Now I'm waiting to get out the salt (I soaked the whole coil in a large bottle with warm water) and after that I will hook up the LC-Meter to check the inductance.

[@OE8ACT]

Getting out the salt is not so easy as thought... I could not find connectors to try it your way.

[@TechDregs]

This is what I used: www.amazon.com/Minimprover-Swivel-Connector-Adapter-Fitting/dp/B08ML1MZNC/

[@silvionannoni5281]

How long is the tube? 35 inches?

[@TechDregs]

Yeah, approximately.

[@silvionannoni5281]

@@TechDregs Today I have make it! 😃

[@silvionannoni5281]

Hello, if uH is 0.544/0.550 is it ok? I came up slightly narrower than yours… 17.90 mm internal But I think yes because the frequency is 118.785 kHz

[@TechDregs]

@@silvionannoni5281 Maybe (I would guess so) but there's no way to know without knowing the specs of the ZVS board you're using. You can watch the previous (part 1) video where I go through the details of how the inductance affects your circuit.