can you convert a 120v mig to a scratch start tig

[muddstopper]

Every now and then I run across older 135amp mig welders pretty cheap. I have a Idealarc 250/250 stick tig machine, but it aint exactly portable. I am just wondering if it would be possible to remove the mig lead and replace with a tig torch like I use on my Idealarc. I realize I would have to modify the mig connections to accept the tig lead, and I havent even looked to see just how hard that might be, but dont want to do it if a mig welder wont work for tig. If those little migs are dc I cant see why it wouldnt work.

 

[dieselcrawler]

Interesting question. Wonder if my little Hobart Handler 140 would be a canidate for the adaption you speak of... I have access to the TIG torch, gauge/regulator, etc.

 

[JimRB]

Handbook - Power Supply

 

[yomax4]

Yes you can. Here is how. Unhook your gun trigger wires. Put a jumper in the socket, pin or spade connector. This closes the contactor. You will know if it's right if the drive rolls are spinning. Turn down wire speed as it needs not run. Take a tig torch ( HW9 or 17 ) with the small threaded connection. Buy a 105Z57 power block at your LWS. it looks kinda like a trumpet. Take a 1' long #4 cable and put a lug on both ends. One end bolts to the eye on the 105Z57 and the other goes to the negative stud on your welder where the ground wire was. Ground moves over to positive. Tig torch hooks to the small end of the 105Z57 and the gas hose hooks to the other and goes to the regulator. Tape the whole 105Z57 so it doesn't touch anything.Now you are ready. Scratch start on your work or I used to use a small piece of copper on top of my part to scratch start on and run off onto the part. It's easy on copper. The problem you will have is being able to turn it down very low. Also the duty cycle is very low with this set up so keep that in mind and have fun. We did this with the little Lincoln SP machines back in the 90's before there were many low cost 115v tig machines. If this isn't clear just let me know and I can make a drawing. Yes this will work well on the Handler.

 

[dieselcrawler]

Good to know... Thanks for the detailed instructions.

Now I just need the proper gas for TIG...

 

[muddstopper]

After posting my question, I did do a search for 120v tig machines. Doing a little rough math in my head, I have about decided it would be almost or just as cheap to by a new Machine. Thats once you consider I would have to purchase a used mig and a tig torch and then all those little parts yomax4 listed. Plus a new tig machine can also be stick and tig, 120/240 volt dual power, I am not sure I would save anything converting a old machine. I am going to keep my eyes open for a really cheap small mig and if one becomes available at the right price, I might consider a conversion. Right now, I already own a 250/250 stick tig machine, and even tho its not really portable, its more than capable for everything I need to weld. The information is nice to know if I ever was in a bind and had to take a machine to the work site, I could convert my 175amp miller mig, but I would only do that in case of emergency and would convert it back as soon as the project was over. In fact, I would probably just mig weld it if I could and wouldnt fool with the tig.

 

[dfkrug]

Scratch start on your work or I used to use a small piece of copper on top of my
part to scratch start on and run off onto the part. It's easy on copper.

That's a good idea, using copper. I might try that next time.

I use a TIG torch with my Miller stick welder, but the only arcs that have been easy to start is on
stainless steel. Mild steel, doable, but not easy. Aluminum, impossible, in my many attempts.

The only real different to my setup, vs. using a MIG welder is that a buzz box already has
clamps for the TIG leads, and you don't have to lock it ON, as with the trigger of a MIG.

A new TIG torch, plus electrodes cost me less than $100. I already had a regulator and
Argon tank.

 

[yomax4]

After posting my question, I did do a search for 120v tig machines. Doing a little rough math in my head, I have about decided it would be almost or just as cheap to by a new Machine. Thats once you consider I would have to purchase a used mig and a tig torch and then all those little parts yomax4 listed. Plus a new tig machine can also be stick and tig, 120/240 volt dual power, I am not sure I would save anything converting a old machine. I am going to keep my eyes open for a really cheap small mig and if one becomes available at the right price, I might consider a conversion. Right now, I already own a 250/250 stick tig machine, and even tho its not really portable, its more than capable for everything I need to weld. The information is nice to know if I ever was in a bind and had to take a machine to the work site, I could convert my 175amp miller mig, but I would only do that in case of emergency and would convert it back as soon as the project was over. In fact, I would probably just mig weld it if I could and wouldnt fool with the tig.

True. I would recommend a small dc tig machine in the 140 amp rage as opposed to using a mig unit. ( Everlast?) Mainly because the tig unit will likely turn down to 5-10 amps and be much more adjustable with a better duty cycle. Plus the switching back and forth gets old. However. The question was asked so yes it can be done.

 

[muddstopper]

True. I would recommend a small dc tig machine in the 140 amp rage as opposed to using a mig unit. ( Everlast?) Mainly because the tig unit will likely turn down to 5-10 amps and be much more adjustable with a better duty cycle. Plus the switching back and forth gets old. However. The question was asked so yes it can be done.

And I appreciate the reply

 

[CalG]

There is a rather large disparity between a constant voltage (MIG) machine, and a constant current (TIG SMAW) machine.
why cant you tig off a mig power source? [Archive] - Weld Talk Message Boards