Don't let anyone try this on your vehicle

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Don't let anyone try this on your vehicleAluminum High pressure A/C line--seal weld, in place on vehiclePatient is almost new, Ford Explorer XLT, some fancy SUV, ego-wagon.Sublet repair from old customer, a Shell gas station/repair service.This one piece line, goes all the way to a rear area condenser, along, and over the frame rails, some 10', so repair was much more palatable than replacing the line---which was leaking thru a pinhole, in the worn crease as seen below in the red circle.http://www.weldingweb.com/attachment...1&d=1196744304Worn areas on a/c lines, creating leaks, are rather common.Any form of welding, in this case TIG (Tungsten Inert Gas—or 'heliarc'], on or in a vehicle raises the possibility of:    -blowing out the ECM (car's computer), the alternator, assorted engine sensors....    ...or if not just flat-blowing them out, then 'disturbing' them, since the TIG, is creating an intense, pulsed, electromagnetic field (the torch and the machine I use, creates a highly focused, pin head sized, jet of plasma gas—at least 50,000˚F--IMHO)    -additionally, there's a high frequency current, superimposed over the welding currentfor that snappy torch light-off and continuous cleaning of the aluminum as it's being welded.-furthermore, that weld area is only 2 1/2" away from the crimped high pressure fitting on the composite rubber hose---any excess heat, will destroy that connection.....and......aluminum takes 3 X the heat energy to weld that steel does, plus having a very, very, very fast rate of transferring heat........to try and melt that hose crimp connection.[IOW—this ain't the kinda job for a buddy of yours and his 110v wire welder]1-Remove your pants belt, watch, anything that will scratch vehicle. Leave your pants on, while performing this work, however.2-Remove car battery, for better access, lines have been bled done, evacuateddisconnected, to place them out of the way. (Anymore, I don't hassle disconnecting the ECM, which is time consuming, can create connector problems, etc.)3-Place lots of fender covers around repair area front and fenders4-Carefully clamp Vise-Grip pliers to the line, very close to repair area5-See that you can perform the hand and torch motions to access the repair area6-Using solid bronze, high end, cleanly brushed, Tweco ground—clamp it securely to the vise grips   [Keeping the ground, very close to the repair weld area, limits the size of this electromagnetic field, that will be created. Grounding, far away, is guarantee, that $omebody will be buying part$---maybe lot$ of part$). A ground that sparks or arcs—will blow a hole thru that line.Proper, close grounding is the critical factor in not damaging other components.]7-Tightly wrap water soaked cloth towel around hose crimp fitting, extending wet cloth onto the line8-Have full, hand operated water spray bottle where you can grab it, along with compressed air hose, to blow water off. Keep CO2 fire extinguisher ready.9-Duct tape shut other open a/c lines, duct tape or wire them out of your way.Weld Procedure1-Select 1/16" dia. Eutectic or Rockmount, high end, high strength, super quality aluminum TIG welding rod. Don't use generic 4043 or 5052 rod for a high end repair. Less porosity, much cleaner welding, since this rod isn't made from recycled beer cans---it's all virgin aluminum.2-1/16" dia. point-sharpened, 2% Thoriated, tungsten electrode. On this job, I first tried .040 tungsten, but the arc wandered some. Step up one size, and the arc was much 'stiffer', without wandering. Electrode dia's. and AC frequency should  be varied to get the arc stability and performance, that one wishes.3-I set max. current at 80 amps AC, current cycling at 20 cycles/second, 10% arc clean, 90%--is heat. Running 'fully-unbalanced' AC, like this—normally works the best—unless the aluminum is really, really corroded, contaminated. Probably the max. amp. output during this wasn't more than 25 amps.I'm wholly, solely interested in getting in, as hot, quick and focused as possible, since I'll only have about 3 seconds-max., arc-on weld time before I have to stop, cool down with water spray, blow off with air; then go back at it.4-Normal pure argon gas, normal flow—15 C.F.H. (I use C-K gas lenses—exclusively,for any and everything that's TIG'ed.....more about that, down the page.)5-For typical 'wear crease', seal weld repairs:-Clean & Tease, high freq. clean, around the crease, very gently. Don't try to get surface wetting, just clean it-first. Cool down and blow as needed.-The blue-outlined circles is where this high bead will be placed.http://www.weldingweb.com/attachment...1&d=1196744304   Drop Your Balls-Tease the arc to just barely see the hint of surface wetting (melting), then drop a lettle ball of filler on this wetted area. Fire off on top of the ball, to fuse it's bottom to the tube. Do not fuse this or any of the balls, nice and flush into the tube--which will restrict the flow. At this point, you're going to be dropping balls all around the outside of this crease area, fusing them to each other and their bottoms, to the outside of the tubing. As more balls are dropped and fused, then go back and carefully tease the ball outer edges to get wetting out to the tube's wall-creating a seal weld on the bead's outside.     Again, you just want to see, the bead wash out, on the TOP of the tubing, smoothly fairing into it---but not having visible material sink down inside the tube.Stay Wet and Blow---Continue the frequent cooling down.Now, the entire crease is encircled by a high bead, wetted and faired to the tubingon the outer edges---only.Don't You Dare-PenetrateDo not let the weld bead, melt or sink into the tubing—since you'll then be restrictingthe flow of refrigerant thru the line. I just let the jet, tease and tease the aluminumlooking for signs of wetting beginning while counting 'one thousand one, one thousandtwo, one thousand three, one thousand four-STOP', in my hed.-FADE out, with the foot control, to stop the arc, gently. You do not want to seeany 'suck holes' or 'craters' forming.....those are microscopic leak points. Fading back out stops that. Carefully wash over any suck holes formed, adding a little filler to the tops, fading IN and back OUT.-Once I see wetting, then add a little bit of rod, keep the puddle very high, to not meltinto the tubing. This takes patience, practice--with lot's of 'cool-downs'.-After the high bead encirclement, then seal off the top of the high bead. Cool it down,again.-Do a visual inspection, then tease with torch jet, again around the entire bead, gentlywashing the edges into the tubing, and looking for any porosity bubbles.--Cool down again, do another visual inspection.......and QUIT WHILE YOU'RE BEHIND.http://www.weldingweb.com/attachment...1&d=1196744304Above welding took about 18 minutes.-There will be some compressor oil contamination of this weld, from vapor exiting frominside the tubing. I just deal with it, by brushing, and and putting more overlay on--carefully.-I normally pressure test with 150 PSI air and liquid soap, which wasn't possible on this repair. I emphasized to the service shop, about my inducing water into the line (slightly) and that they would have to pull vacuum, hold vacuum to boil off the water for 30 minutes, minimum, then recharge and leak test. This repair held pressure.Equipment discussionhttp://www.weldingweb.com/attachment...1&d=1196744304Above is a C-K, Flex-Loc torch—liquid cooled, with the head able to swivel 360˚, silicone tubing leads (which cost significantly more than the cheap, vinyl tubing—but much more comfortable to use, without the leakage problems of the vinyl tubing. I go thru one of these swivel torch sets about every 2 years. This is my 3rd swivel torch,had to argue with C-K engineering, about making the silicone tubing lead sets, then they finally did it—after a year. About $250/torch and lead set.)    -Torch is highly ergometric, one can push or drag with it, left or right hand,out of position, etc.LIQUID COOLING of TIG torches?    -If you're not running liquid cooled, expect short torch and lead life, especially whenrunning high amperage. I use Lincoln Magnum coolers, running distilled water and Dexcool coolant.GAS LENSES    -For any TIG welding I use C-K gas lens assemblies, as shown above. Why?    -Save gas—normal flow is 15 CFH, not 25 or higher    -One gets much, much better, cleaner (that means FASTER) welding with the gas shielding from the lens than otherwise    -Run up to 3/4" tungsten stickout from the cone, and still get acceptableshielding/welding—really handy for bastard repairsSHARP, TAPERED POINT ON TUNGSTEN TO WELD ALUMINUM ON A/C????IDIOT author of this article has sharp point on tungsten for welding aluminum."Any welder knows they must 'ball' the tungsten—first before welding, so the arcdances all around the place, spreads the heat out,  will not go down into a corner,and takes 10 times longer to do the welding""The only tungsten one should ever use for aluminum is pure tungsten—never thoriated.".........All of the above is absolutely TRUE.......if one's using weld machinetechnology designed 50 friggin' years ago.I can't afford to use those kind of monstrous, power glutton machines,the 'professional' shops use. I've owned 3 of them. So, last 10 years, my AC/DC TIG machine has been the Thermal Dynamics, GTSW 300. It's a world-class, inverter TIG, 3 phase. 70#, 300 amp machine, not a 500# behemoth.[A single phase TIG, cannot do the arc un-balancing, or multitudeof frequency overlays, pulsing overlays, etc.--that a 3 phaseTIG machine can do. Nobody's can. There's a bunch of technicalreasons as to 'why'.]              *****Get Paid, Big Bucks To Use a Free Welder****Spent a good $7,800, in purchase, options and maintenance on it.Saved, to date—in actual electric power costs---over $20,000.    IOW-I got the machine, accessories and maintenance for FREE, plus got paid over $12,000 to get sumtin' for nuthin.     I'd sure like to know, what kind of cost figures and math the respected, professional shops use to justify the cost of their old transformer antiques. The main cost savings is the labor saved, not the power, or the gas , or the consumables or repair cost savings........which catapults this technology over the way that granpa ustah due it.    (Sometimes the cheapest to buy is the most expensive to use.)Additionally and most importantly—this type of inverter TIG:-allows one to weld aluminum 5 times faster—minimum thana high end, transformer-type Squarewave machine.-create virtually unlimited penetration—if desired-weld ridiculously contaminated steel, stainless and aluminum,including—WELDING ALUMINUM THRU A PUDDLE OF OIL ON TOP OF IT-weld malleable cast iron—without adding any filler rod The ability to run and keep a sharp point on the tungsten, using thoriatedfor the greatest heat resistance, to help hold the point, creates a tight, focused plasma cone. That focused cone, lets one weld thick or thin aluminum in quick time.[This 'focusing' with sharp point, fully unbalanced, into corner fillets, which I demonstrated to the Miller Factory Welding 'experts' on the traveling Miller Road Show, in 1996........is something that took Miller factory engineering about 4 years---later to realize it was factual, a selling point (which they now proudly advertise)......and that yours truly wasn't playing some trick with their brand new equipment.    The Miller guys I demonstrated that to—just gave me these 'deer in the headlights' looks, after my demo of just what their machine was actually capable of doing. Sometimes, the end users know more about the equipment capabilities than the manufacturer.    You run into all kind of WACKO, WING-NUT JOBS, like your's truly at welding trade shows.]--I have no commercial interest in T-D, C-K, etc. I'm simply stoked on inverters.My next one, will probably be a Miller. Attached ImagesLast edited by dave powelson; 12-04-2007 at 12:01 AM.Reason: get images to show upBlackbird
Reply:Sounds all very cool but the pics don't work.  Ustah - cool word!  John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Originally Posted by MicroZoneSounds all very cool but the pics don't work.  Ustah - cool word!
Reply:Dave,Nice write up of all the reasons and other dancing you had to do for the welding.
Reply:I would have bought a gas saddle piercing clamp and bolted it fast to the leaking line .... First I would hacksaw off the piercing handle.... That would stop the leak for about $12.00... Saveing of $7,789.00....
Reply:Originally Posted by kbeitzI would have bought a gas saddle piercing clamp and bolted it fast to the leaking line .... First I would hacksaw off the piercing handle.... That would stop the leak for about $12.00... Saveing of $7,789.00....
Reply:Originally Posted by dave powelsonSeal welding a/c lines with TIG--is a proven, lasting fix.
Reply:Because Of The Huge Mark Up On New Ac Lines. The Dealerships Usually Only Come To The Welders When They Can't Get A New Line In Time For Their Customer. Just What I've Noticed Over The Years.curly
Reply:I've been TIG welding on high pressure aluminum lines while in service and completly submursed in oil for years, never had a problem.
Reply:Originally Posted by aczellerthen why don't A/C repair shops and dealerships do it?Later,Andy
Reply:i just had a similar line replaced on a 2005 gmc savanah van --warranty covered it. they had to lift the body from the frame to do the job--glad i didn't have to pay for it.
Reply:Originally Posted by dave powelsonI'm sorry, but your repair plan will not work, for a mulitude of reasons:-tubing is not dead round, is aluminum which expands and contracts from extremes in the engine bay temperatures-high pressure cycling can go up to 600 PSI-I don't believe gas clamps are made for this tubing size-even tiny amounts of leakage allows all the refrigerant to escape     Seal welding a/c lines with TIG--is a proven, lasting fix.
Reply:Originally Posted by dave powelson****uuuhHHHmmmmm....I do this for a/c repair shops and dealerships, etc.   Specialty TIG welding is not their business. They either put in a high buck replacement part or have it repaired. The labor and part cost in replacing this lineto the rear evaporator would have been....large---I'd guess over $1200.     My sublet labor was $60, which is my hourly  TIG shop rate.
Reply:Originally Posted by aczellerso you are telling me that a dealership automtive technican would rather pass up an opportunity for a 12 hour job, that can be done in 6 hours or less, depending on skill and speed of the tech, and just give it to someone else? that's interesting... expecially because most warranties would probably be voided if a non-manufacturer-certified technician worked on a vehicle. i'm not doubting you, your skills, or your work... i'm just curious to know why i never heard of this while working in a dealership.Later,Andy
Reply:What is this "air conditioning" you guys are speaking of???Isnt that what the windows are for? LOLMiller blue star 2eLincoln 175
Reply:On a personal note, this post just rubbed me the wrong way.On an experienced note, the saddle valve does work and I know it works up to as high as I have seen it work at 450psi where we had a high head pressure situation and the safety cutout kicked the compressor off. And as for doing these lines on old friggin technology, I am here to post a picture of my homemade adapter which was used to pressure test an evaporator coil. The inlet and outlet hose sizes were different and a premade adapter with hose barbs was not readily available. I cut two barbs and pieced the differing sizes together. This adapter was made using a miller junkbox transformer tig welder. I included a picture of the inside of the adapter for reference to prove that you could do it without burnthrough, causing a restriction. 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