bobcat 225 and tig alum

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need to tig an aluminum oxygen cylinder base back on to cylinder what setting to use with weldcraft tig torch and argon gas.i know i have to scratch start on a piece of copper, it is 3/16 thick aluminum. machine is bobcat 225NT
Reply:you need a HF starter like the HF-251to weld alum with the bobcat
Reply:Originally Posted by retiredIW   need to tig an aluminum oxygen cylinder base back on to cylinder what setting to use with weldcraft tig torch and argon gas.i know i have to scratch start on a piece of copper, it is 3/16 thick aluminum. machine is bobcat 225NT
Reply:Originally Posted by dave powelson"need to tig an aluminum oxygen cylinder base back on to cylinder"Whoa!!!----Apparently you intend to weld an aluminum base back ontoa high pressure oxygen cylinder?????What is this assembly?????Are you aware that any welding on a high pressure--or even lowpressure cylinder, affects the structural integrity of that cylinder?????That apparently what you're planning to do, is a safety issue,where the welded cylinder can subsequently explode, when under pressure??(An oxygen cylinder explosion, causing subsequent other explosions and high-temp, instant flash fires, is more hideous than an acetylene cylinderexplosion.)???What gas supplier  is going to refill this oxygen cylinder after seeing this mod.??
Reply:Originally Posted by dave powelson"need to tig an aluminum oxygen cylinder base back on to cylinder"Whoa!!!----Apparently you intend to weld an aluminum base back ontoa high pressure oxygen cylinder?????What is this assembly?????Are you aware that any welding on a high pressure--or even lowpressure cylinder, affects the structural integrity of that cylinder?????That apparently what you're planning to do, is a safety issue,where the welded cylinder can subsequently explode, when under pressure??(An oxygen cylinder explosion, causing subsequent other explosions and high-temp, instant flash fires, is more hideous than an acetylene cylinderexplosion.)???What gas supplier  is going to refill this oxygen cylinder after seeing this mod.??
Reply:Originally Posted by retiredIWnow you  know  any help with  settings for  machine please.  i know it  can  be  done without the  1000.00 extra equip. miller people told me  so.  maybe i need to  go  to town  and  ask  them  for  more  help huh.thought i  could  save  a drive   by asking here.      thanks  all
Reply:You can't weld aluminum on AC with out a HF box of some kind.  You could possibly do it with DC electrode negative, but it would be tough. The al has to be extremely clean and welded as soon as you are done cleaning it.  There is no cleaning action with DC tig on aluminum.Bobcat has no cleaning or frequency adjustments, just an AC sine wave.David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Listen to Dave.  I have tried it on a bobcat and it doesn't work.  You need a Hi-freq box to weld AC tig off of the bobcat.  and even then to do aluminum takes some work as you have no way to vary heat as you go.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:you can stick weld it with alum rod
Reply:I am curious here guys.....I don't know a damn thing about the bobcat, but isn't it very similar to my lincoln Ranger 9?I bought the tig module so I could have high freq, but I also have a foot pedal to adjust the current. Does the bobcat hf module not have provisions for a foot pedal? If not....uh, why? I mean if they intended someone to need HF, they must have known they need a foot pedal?Like I said...I don't know a damn thing.Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain
Reply:I have a trailblazer 250, which I have added a HF 250-1 box,(the only way to weld alum). I also have added a foot pedal and a thumb dial. The 14 pin connector on trailblazer excepts remote amp controlers, but the HF box useses this connection, so when using HF the nine pin connector on front of HF box has to be used for remotes.Miller TrailBlazer 251Miller HF-250-1Miller MaxStar 150 STLHyperTherm PowerMax 380 plasmaLincoln PowerMig 180Millermatic 252Miller Diversion 180
Reply:Hi-freq boxes are not welder specific.  I mean yes miller has theirs and Lincoln has the Tig madule, but not one for the bobcat and another for the trailblazer, etc....   the one difference is the bobcat does not have a 6 or 14 pin remote plug.  It was not designed to hook any type of amptrol to.  The hi-freq boxes can be used, but not with a pedal.  That was the very reason I bought the Ranger GXT over the bobcats.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:Hammack, gotcha. Yeah, without any amptroller why would you use that setup.... I don't do a lot of tig, but I couldn't do any tig without a foot controller. Now  I do know a guy that used to scratch tig with, get this, the old lincoln ac/dc buzzbox. I didn't believe it till I saw it. And he was welding up oil processing lines for a large corp. I was impressed. I took apart my hi freq module to follow the wiring schematic. That thing is so simple. I don't understand why they get so much money for it. That being said, these modules are no where near as flexible as a dedicated tig machine. You don't get frequency control and wave modulation, which means no square wave or pulsing. But you can get by pretty well with it.Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain
Reply:I use mine primarily for aluminum repair in the field.  It's definitely not a true tig machine but with my current setup I can get nice results.  I used to use a hi-freq on a bobcat, and I got by, but it took sometime to develop a technique without being able to vary your amperage.  Aluminum absorbs heat so fast you have to constantly speed up to keep from melting thru.  Even then it can be quite a challenge.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:I did it with a Lincoln G7, similar machine.  I had to put a capacitor on the output.  I used a century AC HI Freq box plugged into the welder.  It worked.  No foot pedal.  I didn't know it was supposed to look like dimes, so  I just welded with it.  I had a torch with a gas valve on it and a big wire wound resistor I used to get it lower than 40 amps. And ONE pure tungsten.Now I have an arcmaster 185 with a foot pedal.  What a difference!  I can plug it into my Ranger 250 on the road.So yeah, it  can be done with the right stuff.David Last edited by David R; 09-16-2008 at 06:24 PM.Real world weldin.  When I grow up I want to be a tig weldor.