Greetings all,
I have been toying with the idea of upgrading my welding capabilities with
one of the Licoln Precision TIG welders for a while. I currently do a fair
amount of stick welding and oxyacetylene welding, cutting and brazing. I saw
these machines being demonstrated at the last EAA Oshkosh show I attended
and was suitably impressed.

My needs are primarily hobby-based, not production. I'm not really planning
on earning a living with this thing. The kind of stuff I do have included in
the past:
- wood-fired hot water boiler for shop heating, fabricated out of 1/4" steel
plate
- homebuilt aircraft construction
- tractor restoration
- fabrication of components for high vacuum systems and plasma systems for
my research at the university

Materials of interest are aluminum alloys, stainless steel, and the
occasional copper components. Generally, fine control is likely to be more
important than brute force welding of heavy materials...I am thinking
aircraft welding, body work, stainless vacuum components with flanges (1/8"
wall or so), etc. I can always fall back to stick and O/A to join the big
stuff.

I know the basic concepts behind TIG processes, but have little experience.
The Precicion TIG 185 systems look like a nice compact unit
(http://www.mylincolnelectric.com/Cat...et.asp?p=12813),
but the 275 is also nice
(http://www.mylincolnelectric.com/Cat...eet.asp?p=5408).

I have 100 amps of 208 available in my shop. Maybe the 275 unit is too
beefy? At what point does a water-cooled torch become important versus the
air cooled torch? Is the "advanced control panel" (w/adjustable pulse
frequency, on time, background current controls, downslope timer, and other
stuff) likely to be useful, or wasted on a TIG neophyte? And what are the
typical upper limits of material that can be handled by such units (5-185A
DC for the 185 vs 2-340A DC for the 275), for the odd job where a
substantial aluminum or stainless weldment must be joined?

Thank you for any replies,
Al