TIG vs. Gas

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Excellent forum you all have here.  I've been checking it out for a few days now.  I attempted to see if I could find an answer to this, but just doing a simple search on only the word "gas" doesn't seem to turn up anything so I figured I'd ask.I have two welding outfits, a small ARC welder and an oxy-ace kit.  I like the ARC welder even though it is quite difficult to use compared to my brother's MIG, but I must admit it lays down a lot heavier welds than his MIG does.  So, it makes it difficult to do small welds or get into tight corners, and I can't borrow his all the time.  (nor do I want to spend the money on one right now).So, on to my question....I like the results TIG welding gives...a lot more precise, cleaner, etc..etc.. but don't want to drop that kind of money.  I've seen TIG and gas welding loosely compared before, and I wondered how comparable are they really?I know gas welding will never be as good as TIG, but can you get some decent welds with gas that would be otherwise impossible with a stick welder?
Reply:Definitely. It takes a lot of practice, but you can make some really nice welds with Oxy/Acet. If you are welding thin stuff like sheet metal you will get a lot more warping from O/A but with patience and proper techique you can limit that as well. I have watched my dad weld an aluminum airplane cowling from a airplane (cessna 152) with O/A, aluminum rod, flux, and stainless steal wire brush. Welding Aluminum this way takes tons of practice. You can do a bunch with O/A...but in my opinion it takes much more skill than arc or mig.
Reply:there's nothing wrong with oxy-acet welding worked for a lot of years before the other process' were invented. it's slow and requires practice but you sure learn how to recognize the puddle, seen how you can slowly watch it develop.Keep your stick on the ice
Reply:You can convert your arc welder to a tig by adding a high frequency box. You can have DC by adding a full wave rectifier. I will be posting pics of my setup soon. I figure I have less then $400 in the whole works.
Reply:pick you up a air-cooled torch (approx $90) argon bottle, tungsten, and filler hook to your stick machine and go to town. Try this first before you spend $$$ on high frequency box. Is your machine ac or ac-dc?Still lookin for Rock!
Reply:JadecyDoes your Dad have an A&P and repair aircraft for a living? Or was he working on his own plane? I 'd like to see pics of the repair if you have any. Thanks
Reply:From the point of view of an old fart who has been around since TIG was called Heliarc, and smart folks were still figuring out how to use it, there really isn't a lot of differences between TIG and O/A.TIG will be a walk in the park to learn if you have mastered O/A welding.  TIG is faster, and may or may not be more cost effective in terms of inches of weld, depending a comparison of power cost+ shielding gas  -v- cost of fuel gas + oxygen.  Filler rods will cost about the same for either process.I strongly recommend mastering the O/A process first.Appreciation Gains You Recognition-
Reply:Scott, Yes, my dad is an A&P licensed mechanic. He works out of a small municipal airport in north western PA. Unfortunately I don't have pictures. He does all his airframe welding with O/A. He has restored/recovered/repaired many tubular frame airplanes. His real interests are in WWI aircraft and is currently building a full sized Albatross DVa. He is also repairing/restoring a wrecked WWI airplane for Old RhineBeck -> http://www.oldrhinebeck.org/
Reply:I see a lot of posts on how Tig is superior to O/A.  Well, yes and no.  For example, the NHRA supposedly specifies that chrome-moly roll cages (4130 tubing) should be tig welded. I  started with O/A in the '50's and have done a lot of O/A and tig.   Many folks tend to overlook the fact that  for 4130 tubing (light aircraft fuselages, roll cages, etc) O/A may be superior or certainly a little more forgiving than tig.  The difficulty with tig (and mig for that matter) on 4130 tubing is the intense local heat generated at the weld puddle which results in a relatively narrow heat affected zone.  Since the surrounding metal is not heated as highly as with the slower O/A process, the cooling rate is more rapid which can lead to the formation of untempered martinsite along the weld.  This, of course, promotes cracking.  Annealing after welding will prevent this, but is an extra step not normally required with O/A.   Another point with tig and 4130 - cleanliness is better than godliness!  The slightest  impurity will be driven into the weld.   Trace oils will contaminate a weld.  With O/A, minor impurities usually float to the surface of the weld puddle and burn off harmlessly.Back in the days when I was inclined to strap on an aerobatic Pitts and go beat up the sky for 30 minutes or so just for grins,  I always preferred a gas welded fuselage.  (I've gotten too old for that now.  I see that 'ol Franz may have a couple of months on me, but we're still both older 'n God's dog!)
Reply:you are right on your o/a points. only problem is the customer kind of gets upset when you burn the headliner out of his car, and warp the metal in his roof trying to get the top of the joint with the o/a.   l.o.l.      but your metalurgy is bang on.                                                                                                                                                                                                        was anybody elses metalurgy teacher as boring as mine?Keep your stick on the ice
Reply:Originally posted by Jadecy Scott, Yes, my dad is an A&P licensed mechanic. He works out of a small municipal airport in north western PA. Unfortunately I don't have pictures. He does all his airframe welding with O/A. He has restored/recovered/repaired many tubular frame airplanes. His real interests are in WWI aircraft and is currently building a full sized Albatross DVa. He is also repairing/restoring a wrecked WWI airplane for Old RhineBeck -> http://www.oldrhinebeck.org/
Reply:You can correct if I'm wrong, but I believe the only acceptable way to weld a chromoly airframe for the longest time was with O/A. I'm sure at some point they started allowing TIG, but the machines are expensive and a lot of people who did this work already had O/A and didn't see the need to replace it. I learned with O/A and I still love the process when I'm not doing sheet metal work on a car or heavy work that requires stick. The mig beads just don't come out as pretty in my opinion. It works much better in outdoor situations where there is a breeze too. Some of the older airplanes were constructed with mild steel tubing and a lot of them are still flying. Try to get into some of the tubing clusters with a mig, or for that matter with a tig! As long as you can get the filler rod to the joint you can weld with O/A.
Reply:From memory, TIG was still a developmental process, in it's infancy during WW II, and I believe most developement was going on in Europe.I have direct knowlege of B-29 airframes being constructed in the AO Smith factory in ROchester during the Korean War, and stick was the process used.OA was restricted to shipyards during WW-II by government edict, damned if I recall the agency's initials, so aluminum welding, Probably actually brazing, was done with an Oxygen/Hydrogen flame process.  Aluminum brazing was well developed in the 1940s, with Frigidare being a primary developer so they could use aluminum coils rather thancopper in heat exchangers.There have been some very interesting developements in welding processes in the last 70 years.  I have books printed in 1916 that go into great detail on the NEW electric welding process, and how to employ banks of batterys in doing it.  Lincoln once published a pic of one of their early gas drives, around 1930, mounted in a mule drawn wagon, being used to weld one of the first gas pipelines crossing the country.  The electrodes used back then were bare steel wire.  No, they hadn't thought of shielding gas, and it wasn't MIG.It sure will be interesting if I live to see the 120 volt home laser machine, and the questions that provokes on boards if they still exist then.Appreciation Gains You Recognition-
Reply:JadecyThanks for  posting the website. I love WWII vintage myself.
Reply:Franz is right.  Some of the Great Hate II military trainer aircraft used 1020 tubing instead of 4130, albeit with thicker walls and a slight weight penalty.  I seem to recall that a PT-17 (Stearman) I repaired once used 1020.  Yes, I'm an engineer (MSAE) but I have a hard-earned A&P also, which dates back to the days when we had wooden airplanes and iron men.  Franz knows all about that!  It takes iron men to live in upstate NY on a day like today!After fabrication or repair, the procedure was to drill small holes and blow linseed oil or other petrochem compounds into the tubing as a mist as an anti-corrosion measure.  Now that's going to give the best tig welder in the world fits when he tries to do a repair or tubing splice.  O/A is the way to go here!_____________________________________________  ______REAL AIRPLANES HAVE ROUND ENGINES AND TWO WINGS!
Reply:Allright all you airborn bus drivers, just exactly what the hell kind of licenses are you guys getting from Atlantic & Paciffic Tea Company?Since we're talkin airplanes here, not them things RockyD glues & rivets together, but the wood & fabric variety, anybody been to the Glen Curtis museum in Hammondsport NY?  He was one of the fathers of aircraft, and the museum is one of the best kept secrets in the area.Appreciation Gains You Recognition-
Reply:A&P is airframe & powerplant
Reply:Franz, I have not been to the museum. What do they have for displays? I just looked up Hammondsport, I don't see an airport listed. Do you know what the closest airport is to the museum? I am only about 2.5 hr flight from CT to your area.
Reply:Scott, I don't know, but I'll find outI knew I'd get one of you guys to fess up with the Atlantic & Paciffic Tea co line.Appreciation Gains You Recognition-
Reply:Thanks for checking.
Reply:Looks like either ELM or ITH are clocestI can't find any listings for grass strips, but there have to be some in that part of the state.Appreciation Gains You Recognition-
Reply:Speaking of upstate NY, my bride of 42 years is from there - well, not very far upstate, just Newburgh.  Met her while I was driving Uncle Sammie's fighter-interceptors from the old Stewart AFB.I bought her a Chrysler New Yorker some years back.  She actually wanted to get the emblem on the trunk changed to read "Upstate New Yorker" so people wouldn't associate her with that Hillary-lovin' NYC trash.I'm a southerner, myself, y'all, having been born and raised in deep southern Connecticut.________________________________________REAL AVIATIORS FLY TAILDRAGGERS!
Reply:You just might want to break it to her GENTLY, Newburgh AIN'T upstate.Anything South of the Albany - Buffalo line is DOWNSTATE.  We even have the Southerntier over this way to designate where Upstate is.Naw, never mind. Any woman is always RIGHT!Appreciation Gains You Recognition-
Reply:Franz, Thanks for getting those identifiers.ELM is about 5 min farther. It is a 1hr, 12min flight from MMK. By the way, ITH has a 2000' grass strip  parallel to the runway.Art, When I was training, I flew into Stewart a few times.One time I had a C5 either A- not see me,B- not listen to ground's instruction orC- think it would be fun to taxi a wing directly over me as I pulled off onto a taxiway. I think the answer was C.  I am sure I saw the co-pilot laughing. At the time, I did not share in his humor.
Reply:OK, since I have 2 of you air delivery drivers here, do either of you remember the ID designator for AirForce 1 when the President isn't aboard?  I recall it starts with 8, but can't recall the rest.BTW, I don't set foot on those dang things unless they are chained and padlocked to the ground, and I have the key for the damn padlock.Appreciation Gains You Recognition-Franz, I believe they go by their respective tail numbers when the president is not on board, that would be either 28000 or 29000, depending on which of the two they were flying. I would imagine the call sign would be "Airforce 28000 heavy" I am sure that Art will know for sure.
Reply:Oh BTW, If I fly up there, I'll let you know so you can grab your keychain and come up for a ride. Hey you only live once.
Reply:Tail-draggers fly just as nice as tricycles....and, in my opinion,are a lot nicer looking on the ramp......it's just those damn cross-wind landings !  I'll be the LAST one to let you down !
Reply:Scott, the last guy who made me that offer used ot bomb my place with 5# sacks of flour just to prove how good he was.Last one I flew on was built by RockyD's subsidiary, Boeing, and I swear to ya that sumbich was ah shakin all the way from Subic to SeaTac.I understand the physics, the aeordynamics, lift, navigation, and probably could lift one off the ground and definitely land one (gravity assist with no guarantee of post landing flightworthiness) but you would NOT want me in your bird with the engine running.  Unless I'm ****faced, the inner ear thing kicks and I have good capacity.I'm perfectly happy on the ground.Appreciation Gains You Recognition-
Reply:There is nothin worse that somebody losin lunch inside a amll plane, espesially when they are in the back seat, directly behind you!!  I'll give you the botd on the take-off( with a very wide runway and no x-wind) but I would not bet (buy would probably be more like it) the farm on the landing...
Reply:Sure is nice to hear from you guys.  My time was maintaining a PBY in a rescue sqd on Okinawa in 46.  I saw some of the miricles those body men pulled off.  They were ARTISTS!