tig welding with ac or dc machines???

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Hello, I am trying to work on training myself to tig weld, and I am stuck!!!  I have an old Idealarc 250 - the big 400 pound brute, an old ac 225 and an ac 185 as well.  I got a weldcraft 17 tig torch from my cousin and I can get it to work on the big brute, however it doesn't dial down lower than 70 amps - I haven't torn it down to see if it is just needing a cleanup.  Anyway, the 185 does go down to 20 amps.  I have heard of tig welding with it on ac, however I don't know enough about the machines and what is required to run the tig.  I would love any info I can get, I am just at a bad place to go to school and learn this properly, and everything I have learned about welding has been self taught.  SO if there are any places I can read about or anyone who can give me any help, I would soooooooo appreciate the help. Thanks
Reply:You're in the right place... TONS of info here.  Welcome aboard!
Reply:What is the actual model number of your Idealarc?  The Lincoln site has manuals for several versions on line.  I did not go into the manual (not knowing the actual model), but the brief description says they go down to "40 amps of smooth welding power."  Is this too high for you?How did you determine that your machine will not go below 70 amps?  What type and model of meter did you use, if you actually measured the current, and how did you make the measurement?Normally DC is used for TIG on steel and stainless and AC is used on aluminum.  The main virtue of AC on aluminum is that the oxide is cleaned from the surface of the weld puddle on half the AC waveform and the main welding heat is put into the work on the other half of the waveform.  This cleaning action aids in producing a high-quality weld bead in aluminum, but is unnecessary on steelawright
Reply:I have a friend that has been running a very successful welding /fabricating business for well over the past 25 years. the only stick / TIG machine that he uses in his shop is the IDEALARC 250. No Hifreq. No Pulse Tig and he uses a home made cooler, made with a 5 gallon plastic bucket and small pump. He did breakdown and buy a MM251 a few years ago. He has a complete machine shop and welds everything with the above mentioned machines. I was first taught to TIG on his IDEAL ARC 250 with the home made water cooler. I love my high frequency TIG machine and I use the pulse quite often. I still don't know how he still manages, but it not seem to effect this master welder. The man is just an artist and I can NOW appreciate his personal skill and raw talent with these older machines.Mike
Reply:I did not measure the amperage on the 250, I was told that by the man that sold it to me.  I don't know much more about it, except that it is one hell of a smooth welding machine!  Anyway, my tig torch is the type that the stinger clamps onto, so I understood that it is only for welding steel???  I have a mm210 with a 3035 spoolgun for welding aluminum, and have gotten good enough to repair 15+ year old livestock trailers with it.  I would love to learn to tig al, but was told only with a hf or actual tig machine.  I am not sure of the exact model of the stick machines, but the 225 does have the dial adjust front, and the 185 has the 3 electrode holes plus the amperage holes for which amperage you want to use - I can't even find a picture or any info online to post a link to to show what it looks like.  It has a hole for 20 amps and steps up from there by 20 amps if I remember.  I really have to thank you for all your help, hopefully I can get proficient enough learning on my own to make any classes I can take go fast! THANKS!!
Reply:What do you mean, "the type (of torch) that the stinger clamps onto"? Doesn't it have a threaded coupler to an adapter block with a bolt tab for the gas/power connection?  The gas/power block is standard and can be bolted to a welding power plug compatible with your machine that you can get from your welding supply.  It can also be gripped by your stick holder, buy I would go with the bolted connector for best connection.  The type of gas/power adapter has nothing to do with whether the torch can be used with steel on DC or aluminum on AC.  It can be used with both DC and, with an HF unit, on AC with that adapter.If you have a gas supply you are ready to go for steel on DC using scratch start, preferably on a copper block to avoid contamination of the tungsten.  You will need some type of HF unit for AC welding of aluminum, either the internal HF unit from Lincoln (preferable) or an external HF box that your power lead passes through.  Check out ebay for the external HF units for lowest cost.  I had (and still have, but don't use) an external HF box that I used decades ago with an old Sears buzz box but I never got good results with it - probably due to poor technique and to the buzz box that wouldn't even do a good stick weld, rather than the HF box.  However, I think you would be better off fitting a Lincoln HF unit inside the machine if one is available as a retrofit and is cost-effective.You should acquire the complete manual for your machine if you don't have it already.  Once you find the model number and serial number off your machine, you can download the manual from www.lincolnelectric.com.  You can also get very helpful general tutorials from Miller and Lincoln on TIG setups and technique.  The Miller books are very good and worth the $20 or so at your local welding supply.Have fun.awrightLast edited by awright; 06-02-2007 at 01:57 PM.
Reply:I guess I wasn't very clear on the tig torch - my fault, tired!  It is a weldcraft 17 torch with the hose and liner that connects to the gas junction block.  the block has a bolt hole in it as well as the gas connection.  I was told that I needed to hook the gas to the argon meter, hook the electrode stinger to the junction block and slide the cover over it to prevent the stinger from hitting the work, then clamp ground cable to the work and so on.  I also was wrong on the smaller ac welder, it is a lincweld 180, not a 185 - again, tired!
Reply:When you tig on DC, Straight polarity is the way to go.  (Negative Electrode).  Just use what you have.  I have a century HF box and it workes great with my gas powered Lincoln weldmanpower.  Haven't used it in a while since I got my TA 185.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Hey David R, I just picked up a century high freq box to add on.  Is there any way you can help me out here, all I got was the basic box, meaning the box, power cord, and the two cable leads from the box to the welder leads.  My questions are, what torch would I need to use?Is it pretty straight forward as to hooking to the welder?  Could you get me any kind of diagram or pic of how yours is hooked up to yours?I want to hook it up to my idealarc 250, but don't know for sure how to hook it up.  Like I said, I want to get this hooked up so I can learn on my own before going to find a class and get my certification. Thanks
Reply:There should be 2 leads and 2 plugs for more leads.  One says to power and one says to Work.  The power goes through the machine, then off to the tig torch and ground.  The welding wires hanging from the machine go to your power supply and the other ones plug into the century hi freq to torch and work.  You still need a torch with a valve or have to turn the gas on at the tank, but don't forget it on.   We probably have all done that once.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Wow, what a wealth of info you are and this forum as well!!! Thank you so much.I have a tig torch that is supposed to go directly to the arc welder. Weldcraft 17 with  a gas lens.  It has the gas block at the end of the torch hose with the bolt hole and the gas line to go to the argon tank.  Do I just use the same set up with a line bolted to the gas block and the other end to the hi freq?  Also, do I hook it up as ground clamp to welder ground and electrode to welder output?  What way do I set the welder - AC or DC EN or EP?  Thank you for all your help.
Reply:Originally Posted by paynedawg It has the gas block at the end of the torch hose with the bolt hole and the gas line to go to the argon tank.  Do I just use the same set up with a line bolted to the gas block and the other end to the hi freq?
Reply:Ok, I know I am probably asking dumb questions, but I appreciate your help.  When I get this all together and ready, do I need a torch that is adjustable - for example the thumb control or the foot pedal?  Or will my # 17 weldcraft torch with the gas valve on the handle be enough.  I understand I don't need an adjustable for steel, however I thought I read that I need to be able to adjust for aluminum.  Thank you so much for all your help, I can only hope that one day I can be able to help you or someone else as much as you have been a help to me!!!
Reply:When you don't have a foot pedal or fingertip control, its a luxury.  Once you have it, its a nescassity.   (speel that one!).I welded many years with out a romote controll.GO MAKE SOME SPARKS!DavidReal world weldin.  When I grow up I want to be a tig weldor.