Ideas to mod cheap TIG to take foot control?

[SiJ]

Hi All

Been following 19brendan81's thread on import TIGs with interest. I have a lovely old Miller DialArc HF 310amp beast, but no longer have 415V to run it :(, so decided to invest in a cheap inverter TIG, tho with some trepidation. I ended up getting a 200A (DC only) IGBT article off Ebay from Pinnacle in Ballarat, which like so many others it seems is called a WSM-200.... seen at least 6 completely different models with this designation!! This one is sometimes branded Sihio WSM-200.

Turns out I was very pleasantly surprised by the machine, and reckon that for the gauge of stuff I'm doing at the mo find the arc as stable as the big 'un :U. What I really miss though is a foot control (not available on this model).

Have any of you looked into adding a foot control? I have been thinking that I could use the torch trigger connector to add a potentiometer/switch in series with the front panel current control, but there is the complication that this model has two current controls (base & peak for pulse welding). I reckon I would go in series with the base current.

Any ideas? Anyone seen any wiring diagrams for these or similar machines?
Cheers
Si

[Grahame Collins]

hi,
I can only advise that this is not a good idea.
I can tell you this

I am not an electrical expert but have learnt enough from a liscensed and registered sparkie who repairs welders ,including solid state inverter boards that there is significant DC voltage within these machines.

There is enough potential for a bad burn or possibly a fatality.

It is illegal to to perform unliscensed electrical work on welding machines.

Don't risk going to court and a fine if it all goes pear shaped.

Grahame.

[Pete F]

Yes I have considered it and I DO have an electronics background. In theory it should be quite straightforward HOWEVER even with my background I will not be going down that path. I would STRONGLY recommend you don't either. I'm not sure about it being "illegal" in a domestic situation as it's not permanently wired, but as Grahame says there is the potential for it to go horribly wrong. Where you have highly conductive surfaces and high power devices you have a good recipe for a fatal outcome.

The bottom line? If you need to ask the question; don't.

I feel for you as I was in a similar position. If a foot control is what you really want, better to put it up on ebay and buy the appropriate unit.

[SiJ]

Thanks for your responses guys. On re-reading my post I see that I may have appeared a little blase, and perhaps should have given a little more background and a bit clearer explanation of the kind of mod I am considering. I have many years experience of commissioning, rewiring and repairing 3 phase machinery (and as it happens old valve amps) so I certainly have respect for high voltages! Lesson learnt to sound more competent when posting, blame relaxed mind on a few frothies after work!!! :B . BTW, realised on re-read daftness of question regarding base/peak current control! :doh:.

My reason for the somewhat off the cuff post was not to seek instructions, but as am pretty busy at the moment (and the TIG in frequent use), I haven't had time or opportunity to dismantle it to have a detailed look at the circuitry. I was therefore interested to see if anyone else had spent any time researching this and was using the forum as a convenience to tap into anyone else's experiences here. I could (and if I proceed of course will) take the time to fully develop the wiring diagram and system layout of the machine, but this is early days in the project.

Pete, while I realise that your "if you need to ask ...." comment was meant in the best spirit, I do see a place on fora such as this to ask questions about a subject even if suitably qualified, if only to see how other people may have come to a particular/different solution to a given problem. Gotta keep learning...:U. Will post any findings in due course.

Cheers
Si

[Pete F]

Understand where you're coming from, this forum is all about sharing, however also consider that it's not a private forum, rather open to everyone, of all different backgrounds and abilities, and archived, effectively "forever" (however long that is in the virtual world). Hence why I responded if you need to ask; don't

Good luck with it.

Pete