Converting AC stick Welder to TIG?

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Hey guys.  I'm a newbie here to this forum and this site is definitely awesome.  I've learned a ton already just by reading a lot of these posts.  I'm actually a Welding Engineering student at Ohio State University, so I'm definitely trying to soak up as much info about welding as I can.  I was actually wondering how to convert a stick welder to a TIG welder.  I have a 115V AC stick welder that I bought from Harbor Freight a couple years ago.  I also have a 115V MIG welder.  I think the MIG welder runs on constant voltage and for TIG welding you need constant current, so I believe the stick welder runs on CC.  I know they make kits out there somewhere for converting the old buzzbox to TIG, but I am trying to figure out a way to do that myself with just buying the necessary electronics and messing around with the power supply.  It would obviously have to be scratch start without the high frequency converter, and I'd probably just have to use a manual gas valve.  I was thinkin maybe I could use an electronic gas solenoid from a MIG welder, but I'm not sure how that would work.  So, if anyone has any suggestions or ideas on how to make this work, I'd appreciate any of them.  Thanks a lot.Zeek
Reply:Zeek,When I was a "young" buck such as yourself I converted my Lincoln "buzz" box to an AC-DC Tig welder.  Great project but not something I'd recommend doing if you really want to focus on welding.IMO, availabilty and low cost of inverters today just doesn't justify the effort to build your own box if you truely want to focus on your welding skills.
Reply:You will need DC to tig weld steel.  AC to tig aluminum.  The aluminum work requires a HF arc stabilizer.Assuming you want to tig steel, you will need to build a bridge rectifier, buy a tig torch with a gas valve built in, a gas flow regulator and the leads and hoses.  Do some research on the thickness of material you intend to weld, the current required and see if your welder is capable of this work.  The bits and peices will likely cost you more than the harbor freight welder, but who knows, maybe you can cobble together some used stuff.  You certainly don't need an electrode larger than 1/16".  You probably want something smaller actually.  The end result will likely be a unit capable of welding sheet metal and thin walled tubing.  I've found I can weld 0.060 wall stainless tubing with around 50 amps.  If you really want to make this effort worthwhile, I'd start with a 220v welder than has decent current capability.Anyhow, good luck with your project.  I like to tinker, so I understand the interest.
Reply:Zeek, have a look at http://www.az-zbum.com/welder.upgrade.shtml.There maybe useful info related to your project.Good luck.
Reply:I went to that link.  I think his info is good, except the part about using a mig as a tig supply.  This is not advisable, as mig power supplies are not current regulated and regulate voltage instead.  You need to use a constant current supply for stick or tig and a constant potential supply for mig.  On a mig supply, they regulate only the voltage to control arc gap and other considerations.
Reply:Hey Zeek,Glad to see another Ohio Stater on here.  I'm an old shop teacher who learned to weld in that very department your doing your studies in.  That was over 30 years ago.  To bad we lost today.  Good luck on your studies.