That was good, often wondered about flux blead. Maybe it isn't a problem with new aluminum, but I've seen old repairs in Vintage aluminum bodied cars were the weld lines just corode out through the paintwork.
It is very important to wash the flux off the aluminum after welding, BEFORE you hammer the panel or you will drive the flux into the aluminum causing contamination that will cause you grief throughout the finishing/painting process. It can continue to weep out of the aluminum for years.
So, I've been getting a lot of cracks through my primer in areas that were certainly heavily welded and fooled with(I didnt do the work)....does that mean I need to stress relieve or normalize these or whatever you wannna call it and heat them cherrry red with a torch and let them air cool so the cracks don't come back?
Go ahead and try the mig and then torch method. You may learn a useful technique. Set the mig to weld as hot and flat as possible so you get good penetration, and require less grinding. One thing: the metal will always pull and warp when welding. No getting around it. Gas is similar to tig, so you should pick it up quickly. I usually fusion weld as much as possible only adding filler rod when the weld gets a little shallow. Fusion tacking is easy as well. Just hold the two pieces of metal tight to each other and melt them together with the torch. You may have to stretch the tack weld a little to get your panels aligned again. A perfect fit helps. I use aviation snips and then a file to get the perfect fit. I have had good results on panels that are welded together on the bench using the technique of tacking the pieces together about every inch or so, then fusion welding the backside all in one pass, briefly hammer the weld over a flat surface to get the contours back, then flip the part over and weld the seam from the other side, also all one pass...no stopping to hammer until the weld is done. This is a very fast method that gets perfect penetration. The next step is on dolly stretching and smoothing, then shrinking disc, bump up lows, smooth again, shrinking disc again until perfect. Really simple... just takes a bit of practice, and a lack of fear. This is the exact same technique that I use for metal finishing any panel welded, or not. Video in my sig line. John www.ghiaspecialties.com
Hey, I've been told this is especially true of French coachbuilt panels from late 30s on, given to their high use of magnesium/aluminum alloy and its' reaction to the flux. Have you ever seen that? Something like "mudding" over brazing in a 70s kinda repair. I've never worked a virgin, only old restorations on frog tin, but all of the metal was very soft, not jus' the welded areas. Swankey Devils C.C. " it's time for another Tea Party ! "
I was always told and taught never to hammer on a mig weld unless its cherry red hot. The ability to be that quick after setting your mig gun down is pretty hard. I have tried the whole heating the weld up with oxy thing and I dont care for it too much. For one, you put more heat into the panel. BAD. For two, why not just tig or oxy/fuel it in the first place.
Try using a gas mixture with oxygen, as this makes the weld area hotter improving penatration, and extending the cooling period (helping to anneal) I use this mixture to speed up dressing plug welds. I absolutely agree with the guys suggesting "hammer welding" with the torch it's the only REAL way to weld, and if your fusing the butt weld, you don't have to worry about introducing any unwanted alloys. Doug.
The thing I remember most about French coachwork from the 1930's was the number of pieces it took to make a fender. The English had their "Wheel" and access to 4x8 sheets of metal.
Gas welding (oxy acetylene) anneals by nature, making it the most pliable or softest of the three. This is the reason late model vehicles are mandated to be repaired by MIG as to not anneal the high carbon material the panels are fabed from. A panel properly gas welded will never crack as MIG welding actually relies on the bead for strength, most of which is ground off.
Because its?? ...................oh yea, soft. And it was the choice of many a body man too, because it worked good, it was cheap, and it lasted a long time. It had been the choice of many body and fender repairers for many years until they started tieing bales with fibre cord instead of wire. The trend to quit using wire in hay balers starting in the 1970s when feedlot cattle were ingesting the stuff, causing hardware sickness. Just because you don't understand "why" don't make the process a bad one.
A friend of mine is going to try the ESAB easy-grind wire with a tig welder to fill some small holes on a quarter panel.
You can doubt all you want. My TIG and gas welds grind quickly, like butter with a 50 grit roloc. My MIG welds grind slow and wear out rolocs fast with 36 grit. All are ER70S-6 wire. This is about quality restoration work, not body and fender hack work. I know some outstanding car builders, who do excellent sheet metal fab work, and they all TIG hammer weld panels with ER70S-6 wire. Its quality wire steel you buy at a welding supply, not some hillbilly crap left over from a farm. You do NOT have to use junk wire to get a good soft weld. HA! You dont guess about what you dont know? Your the one that stuck your foot in your mouth with your "listen and learn" crap about how the filler wire is what makes the difference and metal not annealing from the heating and cooling cycle, all of which is a load of crap. Everything I and others have stated is not a matter of opinion, but actual facts of metalurgy. Its science, you are not going to disprove it.
WOW !!! You know that adding a different alloy into the weld will change the make up and properties the metal, right at the weld. The same way that pissing in the ocean changes the amount of water. The weld that you find easy to gring and takes to metal working readily is only because, only because, only because, only because, of the amount of heat cycles introduced durring the process. You may have stumbled on something that works but you obviously don't know why. You guess and attribute those facts to the wirerolleyes:=sarcastic) Did I say only because? Those heat and cool cycles is called annealing or softening. The soft bailing wire or tie wire as the iron workers call it is anealled wire, its been heated and cooled slowly a few times and lends it self to tie knots, hold iron fast around tight radii (or hay bales) No one is doubting your torch manipulation skills but you really don't have a grasp on the science.
Ok the whole point of this thread was to see it I could properly finish my panels to my standards with the equiptment I have not to start some pissing match about welding with bailing wire. The answer is YES however it is not the mig. I re-filled my oxygen bottle and ordered some tips. I need to get some good googles and spend some time at the welding table to hone my skills. I'm not welding with bailing wire, coat hanger, or anything other than ER70S-6. the other stuff may work fine but I have some very talented people giving me advice here and their work speaks for it's self. There have been alot of VERY helpfull posts with websites and videos to back up the advice and to all of you thanks. I'll tack weld my patch panels in with the mig and leave it at that until I can get the job done properly and I'll spend some time practicing with the Oxy./Act. and report in with my progress. Thanks Tim Nocero
they just dont make coat hangers like they used to..lol..it would be fun to test some welds to see just how hard they are, this looks like a cool little tester, http://www.corvib.com/equotip/
I've never had an issue with mig welding in sheet metal, then sand/grind down the beads..then hammer/dolly it into place. I wonder if those that have issues try to hammer and dolly thier weld before grinding them down?
Forney makes an easy grind wire in .023. We sell it at Ace Hardware. I've personally never used it. Mostly just convinced people to buy it
As far as the hardness debate goes I work in a aerospace hardening and carburizing facility. I do understand the basic principals I guess I was hoping for the easy answer. When I get proficent enough to lay a nice gas welded bead I'll see if I can rockwell test a mig bead vrs a gas weld using the same wire.
Hey Tim, I was coming back to answer your original question. then i saw your last post. You can if you apply heat cycles to the panel and weld that mimic the O/A heat cycles. If you heat the mig weld zone ONCE it will only normalize the crystals of the metal. (Still probably gonna crack) The "heat tack hammer repeat" across the joint O/A warms the panel well above the ambient temp. (mig wont do that) Then ists the "heat weld hammer skip repeat" that happens next which warm the panel further and the second heat cycle above 1350 F, another heat cycle. Doing it this way provides at least three of these heat cycles, more with the overlap of heat zones. Heating slowly to above 1350 and letting cool slowly (12 hrs) will produce the same results as several heat cycles. If you could find a furnace to put your panel/car into after mig welding it, to do this it would soften things up and allow metal work, and warp your car. Several heat cycles will produce the same results. hammering back to shape durring the process keeps the car straight. Hammering work hardens the metal, heat anneals and the process repeats. Pm me if you need some more info Steve
That makes sense Steve but from a practical standpoint It seems like I'll probably be doing more damage to the panel with warpage than I am capable of fixing. I need to either hone my skills at the Oxy/Acy or spend the money on a Tig. I'll keep you posted on which route I end up going. Thanks Tim
i also worked in a plant that had its own enamel funace, the metal we used was low carbon enameling steel we called it, that stuff welded beautifully with OA, we would just shear off little strips to use as filler, you know how you get little sparks comeing up as your running a bead in mild steel well the low carbon stuff was just about spark free, flowed like honey, the last i heard there was talk of a new mig wire comeing out made of the same material, i dont know if it ever happened
I snagged an idustrial tig off evilbay for 400. they are usually cheap 3 phase. look up "roto converter" on google to run 3 phase equipment of single phase 220
There is no reason you cannot get a perfectly metal finish panel using a MIG welder. Here is a link to Randy Ferguson's explanation of how he does it and I don't know if most could do a better job metal finishing a panel with any welding method. http://fergusoncoachbuilding.blogspot.com/2007/04/mig-welding-thin-sheetmetal.html
Lots of information in a short video but I have a question, could propane be used instead of hydrogen? It is clean and burns cooler than acetylene and its cheap.
When gas welding...if you are concerned about the quality of filler rod, cut a thin slice off of the parent metal to use as a rod. Aviation snips that are in good shape will cut a very thin strip. You can also use the trimmed piece from your final fit before filing the edge to fit. One side benefit of this technique is you are not wasting heat melting a thicker than necessary filler rod. No question about whether or not the rod is right either. John www.ghiaspecialties.com
I doubt that you have trouble grinding either one. It's a fact, a soft wire weld hammers easier than a steel wire weld. Throwing in red herrings to distract me from that premise just don't work. Foot removed. Which part of the filler wire is what makes the difference do you disagree with? If you starve the weld and use less fill wire the weld will be composed of mostly parent metal, if you flood the puddle with more fill rod, the weld will be mostly fill rod properties with a boundry of both. With a soft iron fender with soft iron rod the weld will have less tendency to crack than if it's a soft iron fender with standard mig (steel) wire because the weld will be more likely to fatigue crack from the mix matched recipe. As John Kelly (above) reminds us "When gas welding...if you are concerned about the quality of filler rod, cut a thin slice off of the parent metal to use as a rod. Aviation snips that are in good shape will cut a very thin strip." Chad S, You seem to think your work is higher quality based on your opinion that a farmer can't weld as good as you. Your opinion that your way is "quality restoration work and somebody elses is "body and fender Hack work" Dream on sir, you are sadly mistaken. So when somebody says something you disagree with, you lower yourself to calling their way "shit" and "crap", and spout theory. I haven't said one single thing that I haven't learned by doing it, and nothing I said will prove out to be wrong if you simply try it for yourslef. Your attitude that you have to attack people you disagree is noted.
Back to the q. I do sheet metal with flux-core wire-feed nowadays. For you Nocero. I used to prefer, OA, since my eyes just don’t see the puddle as clear as I used to, on sheet metal,(my recent is Nash Hot Rod, I use flux-core wire-feed. It works good and I’ve never found it “HARD TO GRIND”. Soft wire makes them easier to hammer. There’s a mix. But if one tries to get the surface perfect, depending on grinding and hammering, without using fill, then the surrounding sheet metal is going to be ground, thinner. I prefer a good sound weld joint, grind off the High Spots, then fill. People that diss using (filler, bondo, skim), can do that, but it's unnecerssary to me. I realize that a welder/body repairer that says they don’t use it simply mean they send it someplace else to get it finished and painted. Painters use (filler, bondo, skim), all the time. It’s pure utopia to say (fill, skim,) is not to be used on a welded sheet metal repair.
You are the one stating incorrect info as fact. You clearly do not understand the science behind what is being discussed, and your information is misleading. I dont disagree with you because of a matter of my opinion, its a matter of science and metalurgy. You cannot change the laws of physics. I dont understand why when I or someone else here states factual information, which is based on science, and proven by people much smarter than you and I, (that just so happens to negate your information) you find it necessary to prove it wrong. Once again, Science will always win over opinion. Once again, you stated that the difference is in the filler material, and not the heating cycle (MIG vs. Gas vs. TIG), and that is wrong, wrong, WRONG. Its not a matter of trial and error, its a matter of science. What you dont seem to want to understand is that its all about the cooling cycle. Another poster already mentioned that this Bailing wire you use is an annealed wire. When you heat that wire to a molten state, it is no longer an annealed solid. Once the metal is molten, the final hardness of the cold, solid metal is all in the heating and cooling process. Therefore if you were to take that bailing wire, heat it up very quickly, and cool it very quickly (i.e. simulate the heating/cooling cycle of a MIG weld), it would no longer be a soft, malleable metal. But because you are using it to weld with a gas torch, which is a much slower cooling cycle, it is being annealed again (once its solid) and is very malleable. Does that make sense to you? Thats not opinion, its SCIENCE!
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