Transformer Tig

[Paul]

Advice buying used Tig

I want to buy a good quality used Tig welder, transformer type.
Can anyone recommend what I should look for? what make model?
What would be a good second buy? if I could find it.
I have only single phase but have read something in the forum, which I cant find anymore, about some of the three phase machines can also be wired up for single phase.
I would like to weld mild and stainless steel.
would be grateful of any advice.

 

[malcolm]

Can help a little but not much. For steel welding you'll only need a DC TIG. That saves a lot of money on secondhand units as everyone seems to be after the AC/DC TIGs that can do aluminium as well.

Go for one with a HF (high frequency) start rather than a scratch start. Makes starting the arc so much easier.

The big names - Murex, ESAB, Miller, Lincoln would generally make the better welders. Buying from the bottom of the range from one of them is likely to bag a better welder than buying from the top of the range from Draper or some Chinese outfit.

It was probably me that wrote about the three phase/single phase thing. My Miller Syncrowave is designed to run off 2 of 3 phases (more input voltage that way) but has jumpers that allow a lower input voltage to be selected. The Miller is a fancy old welder that weighs more than an elephant and is as big as a double decker bus (I gather it's designed to weld football fields :eek. More sensible welders probably won't allow the option and will be either 3 phase or single phase.

 

[Paul]

Thanks for reply Malcolm.
How will I know when I see a Tig if its High Frequency start? Is there a way of knowing.
And about the single phase, do they say single phase on the welder? I can imagine the electrical information on a welder would be mindbogling to me!

 

[Ratty]

I imagine single phase would have a normal 3 pin plug and 3ph a socking great big cylindrical one (or you could always ask the seller). Don't ask me about HF start tho - that's just double dutch to me.
What is 'scratch start' anyway? I keep seeing this and it means nothing! (and while I'm here..what's HF start?)

 

[bump]

HF is High Frequency start, where the welder uses an initialisation arc to get you going, where as scratch start is a bit like stick welding.

 

[Ratty]

thanks bump, so scratch is a literal description? I know I scratch arc rods all over the shop to get started!

 

[Paul]

Hi Ratty, I gather HF start means you dont have to touch the work piece with the tip to start the ark.
There is plenty of three phase equipment where I live, but I think some of them can be also wired up for single phase?
I would rather buy a proper secondhand three phase machine than a new cheap machine.

 

[MrFluffy]

You say you have only single phase supply, Im under the impression you cant run a 3 phase tig from an inverter for some reason, I have been told this by a electrical engineer I know. Only devices powered by motors, something about it sustaining the phase generation that way??

Lots of 3phase motor powered kit here seems to have a option to rewire the motor windings to single phase but then instead of 415v@6a you get 240v@20a or something silly that the wiring cant support without extra capacity work...

 

[Paul]

Thanks Mr Fluffy, Thats what someone told me that you cant run them on a phase converter.
It gets a bit beyond me the electrical phases and volts. I still dont understand why some electric motors are three phase but are stamped 415-
240 volts.

 

[MrFluffy]

Theyre the ones you can change some links inside to make them run from single phase I was talking about.