Assistance required on which TIG welder to buy...

[datsunsss]

Hi guys,

My name is Jared and I am new to the forum and I am hoping somebody here could help me with information with regards to which TIG welder I should be looking at.

I am going to be doing sheet metal repair work on my 1971 Datsun P510 SSS Coupe and will most probably be working with 1.0 - 1.2mm thick sheet metal. If all goes well I want to also be able to fabricate a stainless steel exhaust manifold and system as well as an intake manifold.

I would like to know, based on the above, what size welder am I supposed to be looking for? What amperage range should the welder be able to handle for these thicknesses?

I am currently looking at the following two DC Inverter welders (first 2 on page): http://www.e-weld.co.za/index.php?option=com_content&view=category&layout=blog&id=64&Itemid=48

Am I heading down the wrong track here?

Hope to hear from you guys soon.

Kind regards
Jared van Bergen

 

[Wozzaaah]

You're slightly on the wrong track, both those machines are ARC welders, not TIG. They can probably be fitted with valved tig torches to allow you to tig weld with them but they don't have HF circuitry so you'll be limited to scratch starting the arc.
For the sort of stuff you mention, you don't need anything bigger than 160A but tbh, a mig welder is more use than a tig welder on car bodies.

 

[astro_al]

I agree - sounds like you'd be better off with mig.

As for power - I don't think there is a welder built that can't handle material in the 1mm range. You'd be better off looking for a low minimum output than a high maximum output.

Al.

 

[datsunsss]

Thanks for the replies guys.

Is there any specific reason why I should be looking at MIG? I was under the impression that TIG would be better as it does not disperse the heat as wide across the welded sections, thereby reducing warpage when done correctly.

Also, I thought you must buy an Inverter machine for use as a TIG machine for mild and stainless steel, and an AC/DC machine if you want to weld aluminium? Am I wrong here as well?

Regards
Jared

 

[Wozzaaah]

TIG effectively puts MORE heat into the weld so is more likely to cause distortion.
The main reasons mig is ideal for bodywork is that it can be done one-handed, can be done in very short bursts, is MUCH quicker and is much more economical.

You're right about TIG welders in that DC will weld most metals but AC is used on aluminium.
Inverter is actually the type of machine, they use electronics to create the welding current whereas thyristor/transformer machines use heavy coils.
Consequently, inverter machines are very light and transformer ones are very heavy.

 

[datsunsss]

Will I be able to weld stainless steel with a MIG welder? Also, if I do go with a TIG machine, does 20-180Amps sound fine for my intended application?

Is it a train smash if the welder does not have 2T/4T functionality?

I think I am just confusing myself here more than I should be haha, making my life difficult as I want to buy something that I can use for the next 5-10 years but am on a tight budget at the moment.

Regards
Jared

 

[hotrodder]

You can weld stainless with MIG, more detail here... http://www.mig-welding.co.uk/stainless.htm (put the kettle on have a read through the rest of the tutorial pages, lots of useful stuff there). 2T/4T is really just a different way of operating the trigger, with 2T you press and hold to weld whereas 4T means you don't need to hold the trigger down

For bodywork unless you're very handy with hammers and dollies TIG will be a headache. It's a different approach that has more in common with traditional coachwork- distortion is accepted and dealt with when planishing out welds using a body file to highlight low spots and then bumping them up and planishing them out. By contrast, with MIG the goal is typically to minimise distortion and then grind/sand the weld bead down

20A bottom may be limiting, for example for 1mm mild steel would typically be welded in the 25 - 35A range. Beginners often find they need less amperages due to lower travel speeds (which'll compound distortion issues). MIG or TIG machine, for automotive type stuff low end performance is typically a bigger deal

 

[datsunsss]

Thanks for the info hotrodder, interesting points you make there. If I do decide to go the TIG route, will the Clarke AT131 welder be a good buy? It seems it can do very low amps which I take is a good thing for what I want to use it for?

 

[hotrodder]

That Clarke isn't a TIG welder, it's a DC inverter that can be used for 'scratch TIG'. It's designed primarily for stick welding (the only control is amperage) and as a result the torch is permantly live- gas is controlled manually via a valve on the torch, you have to manually strike an arc (kinda like striking a match but a skill in its own as you have to do this without damaging the tungsten) and 'snap' the torch away to end a weld.

It doesn't mean it's useless for TIG work but it'll be a lot harder to use for what you have in mind than a proper TIG machine. As well as being less friendly to use the nature of this type of work is lots of tack welds and short runs- a manual gas valve is far from ideal and will probably at least double gas consumption