Tig welding

[F Murtz]

Ihave an older unimig 175 which seem to be the same as a unimig 190. it has three knobs,current voltage and wire speed,a euro socket for main mig cable,two sockets for dc,positive and neg, and a four pin din socket for spool motor I think. There is a three position switch for mma mig and tig With the tig I just plugged it into the negative socket with pos earth and it seems to work but I have not got a handle on tig welding yet, it sticks all the time,I have trouble maintaining ark, I tried aluminium with argon but not much success and I tried steel with argon, I have welded steel with oxy acetylene on and off all my life and even aluminium with oxy many years ago,so I thought tig would be a breeze. I do not know the best settings for current and voltage for tig as a beginner, or even if the voltage setting is applicable for mig Any ideas. Don't know if there any TIG experts here.

[Andy Burns]

There may be one or two in the woodwork, otherwise This old Tony or

6061.com on youtube, the former quite practical, the latter a bit showy and (obvious from the name) mostly aluminium.

[nothanks]

I am very far from being an expert (and can't help with the settings) but I find TIG welding more enjoyable than MIG or MMA, if slightly frustrating. Some thoughts, FWIW: keep your tip sharp and re-grind it as soon as you get a bleb on it, work forwards and dab the filler into the pool (setting-up a rhythm), get the technique sorted on steel before trying aluminium. The best thing would be to find a short course nearby, or to pay a "proper" welder for half a day to get you going.

[Fredxx]

I also thought AC was recommended for Aluminium? To break through the oxide.

Whenever I have watched YouTube videos on TIG welding they've made it look so easy.

[newshound]

YouTube videos of any sort of welding make it *look* easy :-(

[John Rumm]

Yup, they normally have an ability to vary the mark space ratio of the (square wave) AC output as well, so you can balance the amount of "cleaning" you get.

IIUC you can MIG ali on DC with a spool gun, but for TIG you need AC for ali

(having all the settings for ramp up and down, and pre and post flow of gas helps - as does high frequency start so you never need to touch the steel with the electrode to start the arc).

[AJH]

Is this scratch start TIG? Do you have control of the gas independent of the arc and can you switch the arc off other than by withdrawing the tool?

I have a simple TIG with scratch start but the gas is not controlled at the torch and neither is the arc, it is not particularly usable other than for mild steel as the gas protection ceases as the tool breaks the arc and you can see an oxide blob erupting with stainless . My mate's one has a high frequency start, the gas is controlled by a trigger on the gun and he has a foot control to ramp up and down the current.

[Cursitor Doom]

If you're fine with oxy/acetalene welding you should have no trouble at all with TIG, but if you *are* having trouble, it can only be due the usual problem: you need to get the settings correct. And make sure you have a solid earth.