So, after giving a shit ton of advice on welding cast iron, I noticed that my cast aluminum supercharger bracket had broken! Is it better to TIG or Heli-arc cast Al? Does it depend on the alloy? I should know this, but I don't....kind of cast-ironic, isn't it?
[ QUOTE ] Is it better to TIG or Heli-arc cast Al? [/ QUOTE ] Is that a trick question? I don't think the brand of tig is going to make an alloy-specific difference.
Not an expert but, I have used both at work to weld cast alum. I prefer the heli-arc myself only cause to me it is easier. I would think if you have both at your disposal either should work fine.
[ QUOTE ] TIG and heliarc are two names for the same process. Frank [/ QUOTE ] Tig is hand fed wire simular to brazing using a tungston electrode sheilded in gas and you feed the alum rod in by hand(Tungston Inert Gas). heli-arc is wire fed like a mig(Metal Inert Gas) only different gas is used than you would use on steel and alum wire of course.
PDXlefty, Heliarc was a term used for tungsten inert gas welding long before wirefeed was applied to it. Frank
Since we are on a semantics pissing contest, i think you should use GTAW (Gas Tungsten Arc Welding). Seriously, use TIG (Tungsten Inert Gas) or Heli-arc, either one is an unofficial term for the same basic process, although heli-arc implies helium as the gas and most of the time Argon is used. Helium lighter than air and used for overhead typically, Argon heavier than air and used for flat. Your filler will most likely be 4043 Alum alloy, that is the almost universal alum filler material. There are some others, but 4043 will work fine. Just make sure to have the surfaces real nice and clean.
TIG stands for Tungsten Inert Gas. Heli-arc uses Helium as a shielding gas. Since Helium is lighter than air,it is perfectly suited for overhead welding. Argon is heavier than air,so it's better for flat work. Most people use Argon as a shielding gas for doing TIG. Take it to the best professional welder you can find,let him worry about it.
you guys are cracking me up. heli-arc is a brand name associated with tig, or GTAW for you welding engineering students.
well, I guess that solves it then... the reason for my confusion is, at the place I used to work, we had a huge, yellow, metal box with all kinds of dials and switches on the front of it, the boss told me it was a "heli-arc." This last summer, I helped a friend build his model a, and he taught me to TIG weld with a smaller, blue, metal box with 2 switches and one dial...
[ QUOTE ] PDXlefty, Heliarc was a term used for tungsten inert gas welding long before wirefeed was applied to it. Frank [/ QUOTE ] First I've ever heard that. Thanks.
And throughout all the sementics "lessons", no one cared to mention the MOST important thing about welding aluminum via the GTAW process: PREHEAT THE SUMBITCH!!! Otherwise you will have what is technically known as a warped piece of shit. All you need do is pop that baby in the oven at 350-400º, pull it out and weld it. Might want to use gloves... Oh, and if the welding takes a bit of time, re-heat it. Cosmo, who learned the hard way...
[ QUOTE ] And throughout all the sementics "lessons", no one cared to mention the MOST important thing about welding aluminum via the GTAW process: PREHEAT THE SUMBITCH!!! Otherwise you will have what is technically known as a warped piece of shit. All you need do is pop that baby in the oven at 350-400º, pull it out and weld it. Might want to use gloves... Oh, and if the welding takes a bit of time, re-heat it. Cosmo, who learned the hard way... [/ QUOTE ] Damn this is school night for me. I never heard about preheating alum. But all of it I have welded have been large pices that would be difficult to warp.
[ QUOTE ] Damn this is school night for me. I never heard about preheating alum. But all of it I have welded have been large pices that would be difficult to warp. [/ QUOTE ] Well was it CAST aluminum? I can only weld any aluminum if I preheat because I don't G.T.A.W., I only O.F.W., and sometimes G.M.A.W. but don't G.M.A.W. on aluminum, so D.A.M.
Oh it was Cast. Some times nice and clean and other times nice and dirty. So how do you clean dirty cast when it has seeped into the pores? Sure get a bird shit ugly weld when it is dirty.But I don't work there any more so W.T.F. do I know any way. Thanks for the education.
use M.E.K. when you G.T.A.W. so you don't get a B.S.U.W. seriously though, mek cleans good, it's methyl-ethyl-something I don't remember.
[ QUOTE ] So how do you clean dirty cast when it has seeped into the pores? [/ QUOTE ] Clean as good as possible, then grind it and V it out real good.
If it's in an area that is prone to cracking again, gas welding is actually best. But this isn't easy unless you have the Tin-man's blue lens, the Henrob torch, the proper flux, and a bottle of hydrogen (oxy-hydrogen welding)-- and experience. TIG will be easier, but produces a harder weld that also has stresses on either side of it-- not good for doing cast aluminum where it's prone to cracking again, like around bolt holes. Best you can try to do is to stress-relieve or anneal.
Why hydrogen? The only reasons I've heard for people using it before were from aircraft restorers who use it because that's what was used in WWII, but it was only used in WWII because it was cheap and accetylene was rationed. I would think the more focused accetylene flame would be better especially on a metal that's going to spread the heat away from the weld so fast anyway.
If you heat the alum. to 400 degrees before welding, you can weld it with the tig and it would/will be the same as gas welding alum..... Pre-heat/weld/post-heat HRD
Yes, preheat will help to stress-relieve the alum so it does not warp, actually temp of 200 for about 4 hours after welding will stress relieve alum. Alum can be cleaned with acid to remove the oxide and any coorsion type stuff, but acid will not touch grease and similar. So clean with any good solvent like MEK (methyl ethyl ketone) or other. MEK can be hard to find in air quality restricted areas, but acetone, lacquer thinner or whatever can also do the degreasing job. Then a little grinding to get good penetration and a full weld. The technique of using a stainless wire brush right before welding is to help remove the alum oxide on the surface, same reason alum is TIG/GTAW/Heli-Arc welded using AC. The AC helps blow off the oxides. Damn jake, you sure got me posting about welding the last two days.....
I just mentioned hydrogen instead of the sooty acetylene because it burns cleaner and introduces less (or maybe no) contaminents into the weld. This is the best way to go when welding aluminum sheetmetal. Might not be critical for castings. I guess I was just thinking of the "ultimate" gas-welding setup for doing aluminum with gas.
I've heard that when dealing with cast, it also helps to bury your part in dry sand after heating to let it cool very slowly and uniformly. Never done it but it seems like a good idea.
Well people have different preferences, but most people prefer accetylene to hydrogen for steel or aluminum (of the few people who still weld aluminum with OFW--Kent White (Tinman) being one of them). Accetylene is only sooty when the flame isn't nuetral, which helps a welder make sure the flame isn't oxidizing. An oxidizing flame will kill chances of welding aluminum well. Whatever works for you, but I wouldn't want to try to learn aluminum with hydrogen. Then again you're using a Henrob which might explain some preference differences right there.
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