Glad you liked it!

That’s awesome and I’d love to see a picture of the bobbin and reed switch assembly!

@@JakevonSlatt - aarrgh!!!! My replies keep getting deleted. 😥 Presumably because there's a link to a (Google, which owns KZfaq) photo album. How else can I send you these pictures? ❓

@@peeteebee123 put the text in without the “https” part and I’ll type that by hand.

You are correct sir! There are now relatively inexpensive pilot arc units on the market, not so the case when I bought mine several years ago.

You bet!

Thanks for watching!

They are indeed!

Thank you and best of luck getting your machine working!

Yes, if the cutting current drops out the pilot arc will kick back in.

Have you seen this video? kzfaq.info/get/bejne/n8p7lZVlm9fScZ8.htmlsi=Xtlj1xQHlzvq0DS6 it’s the shield cable and the capacitors that I think solved my RF problems. Also I recently heard from another view that they made a bobbin with a reed switch in the center of a couple of turns of wire and it worked without ferrite or an iron pipe ring.

Hmm, I used a generic torch like this: www.ebay.com/itm/265701724204?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=-ueydqfvR6O&sssrc=4429486&ssuid=SIF5RPlxTlO&var=&widget_ver=artemis&media=MORE it was about $35

I did get the photos, thanks! This sounds viable, but it will take some trial and error to get proper isolation. Do a search for “DIY TIG HF start” projects, there will be some good information on how to keep the hf from blowing up semiconductors in welders.

Oh! That is interesting! I'll have to run some tests to see if the consumables hold up.

I actually started with a hall effect based current sensing relay but the RFI blew up the semiconductors after about five minutes. Next I tried a current shunt with op amps, but had the same problems. When I first built the CNC table, I had terrible RFI problems that would crash the controller, If you look at two or three videos back, you’ll see what I had to do to get the cheap CNC controller Stable. When I was researching how to protect Hall effect sensors from RFI I came across a webpage that talked about replacing reed switches with Hall effect sensors, and I remembered that I had a bunch from a job I worked about 20 years ago, and I thought I’d give it a try. The whole device came together within a couple hours after that.

I think an Arc Good signal could just be taken from the relay. Arc voltage is something I haven’t dived into yet, though THC is something I’d like to add in the future.

To get arc voltage you’d have to use semiconductors somewhere, so you’ll have to deal with the RFI and collage spikes somehow. My quick thoughts are to use an analog-out (linear) optoisolator to get the signal out of the box while protecting your controller circuitry. - use a transformer to get a floating power supply for the voltage-sense circuitry. (You might want a separate one from what runs the relay, I think the wires coming from the reed switch would couple-in a lot of nasty noise.) Filter the heck out of the power, series choke, maybe out the analog circuits in a small grounded metal box(?) - Use an op-amp with appropriate input divider to measure the voltage between the arc positive and ground. (A differential-input or “instrumentation” amp might be useful or necessary to help cut noise, but I don’t know if that would be necessary.) Use an RC network between the voltage divider and the amp input (or just bridge the low-side resistor in the voltage divider with a cap) to cut the higher-frequency noise. (I’m guessing that you wouldn’t need more than ~3-10 Hz bandwidth for your THC control output, so get rid of any higher-frequency stuff as early in the process as you can.) - Have the output of your voltage-sense amp drive the input of the linear optocoupler. - Run the output of the optocoupler to an external interface board that’ll use another op amp circuit to produce the level of voltage the controller needs to see. Use well-shielded cable to carry the signal, with the shield of the cable grounded at the controller side only. That’s just an outline, there’ll be a lot of calculating and tinkering to get to the final circuit. The basic idea though is to use a linear optocoupler to isolate the arc voltage measurement from the controller, to use a floating power supply for the arc measurement circuit, and to connect the shield of the cable running to the controller side to the ground of the controller. (Do *not* connect the other end of the shield to anything on the plasma cutter side or you’ll create a ground loop and possibly fry your controller.) I hope this helps, good luck! (It’d be fantastic to have an open-source solution for THC!)

I think that a piece of iron pipe probably will work! Thanks for the kind words!

I think the cheap pilot arc units are probably just fine, with the possible exception of RFI. I've only ever use my cheap "contact" unit which was indeed a nightmare with respect to RFI! This video documents what I need to do to keep the CNC controller from crashing whenever I lit the torch: kzfaq.info/get/bejne/n8p7lZVlm9fScZ8.html

@@JakevonSlatt Thanks! I wouldn't be surprised if they're noisy too. I'll check out that video.

All high frequency will have issues with electronics. I fried a motor controller with my Miller Dynasty DX as I welded too close to the circuit board

Te salio?

@@AserraderosMikuman todavia no hice la plaqueta con los capasitores y no encontre el lugar para poner la maquina con todas sus conecciones por lo pronto tiene una fresadora puesta , pero sigue en pie el proyecto no falta mucho, el aparato que muestra en este video ya esta hecho y funciona muy bien

Once the arc is established it will continue to cut, regardless. With an hf start torch contact is required to start the arc. With a pilot arc torch you can start the arc without contact. This is advantageous on a CNC table because it helps prevent molten metal being blown up into the torch ruining the tip.

@@JakevonSlatt Thanks for the swift reply Jake. Another quick question if I may; Could you not just have a simple Momentary Switch to initiate the Pilot Arc, which you could just release once cutting is started? You'd hold it 'on' to start the Arc (along with the main Switch), then release it to open the Pilot Arc Circuit.

@@Docv400 you could do that, but if you were making a complex part on a CNC table you have to stand over it pushing the button

@@JakevonSlatt Understood. I'm only doing manual cutting at the moment, but am planning a CNC build also. I suppose you could wire a relay into the circuit, which could be controlled by a CNC Controller output.

There are good cheap pilot arc torches out there now that would cost less than a custom build, this sort of thing only really makes sense as a DIY project build with parts already on hand.

Totally understandable.

I not sure I understand the question, can you rephrase?

He may be referring to multi-function combo machines, like the Vevor CT520D machines I've seen that claim to have Stick, TIG and plasma cutter functions in 1 machine.

@@vonnorman6737 ah! This is the only machine I have any experience with so I don’t think I can be helpful here

The voltage is way higher around 90-110 volts in order to break the air into plasma. Tig is 20 ish volt breaks down argon easily. You want to plasma cut with a tig. Change the torch and use high pressure argon. It will cost you some argon😅