TIG Anodized Aluminum..

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I grabbed a couple of pieces of anodized and tried my hand at welding them up..  I put a slight bevel between the pieces and cleaned them with a stainless steel brush..  The puddle was not easy to start and did not really want to stay running... had to put a lot more heat into it than non-anodized.so in some spots it began to push/melt through.. So with that being said, what did I do wrong...  And what else do I need to do?  I was told to get some denatured alcohol and wipe it down (after I had already welded it up... so it was too late.. )  I will post pics tomorrow...  ( I know it is hard to diagnois without pics ) I thought about taking a polishing wheel and scuffing up the surface around the bevel to enhance the weld quality on top side.
Reply:not sure on the exact reason but possibly the anodize melts at a higher temperature then the aluminum it self like millscale but again i may be wrong so dont acuse me haha6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:It is not a good practice to weld anodized aluminum.The reason is that the anodized surface has a thick oxide layer and that is working against you when welding. The signwave is trying to "clean" oxides from the surface that are built up. The surface of anodized aluminum is a different crystylinestructure that is harder for more corrosion resistance.If you grind off the anodizing it would help but it is still messy and not structurally sound.Maybe it would be necessary for a repair but i still would not want to do it on aweldment that could be life threatening. Barbeque grill OK.Last edited by Donald Branscom; 06-11-2008 at 12:50 AM.
Reply:Donald,Obviously you've never heard of welding a tuna tower on a boat.  Towers are anodized aluminum and are welded every day.  And yes, they are structural welds and people do stake their lives on the integrity of the welds.Do a search on millerwelds and you'll have it explained for you.Trick is to run hot and run fast.  We use what is referred to as the "bump" technique.Bad advice is worse than no advice.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Sundown is dead on. The bump method is done usually with a button on the torch instead of a foot pedal.Hit the button, and it's wide open. Let go, it's off. The key is to start hot; I am hitting at about 185-225 amps. BAM, hit the arc, and be ready with the filler. Dab heavily, and you will see the anodized push to the outside of the weld puddle; it leaves the center clean and easy to add filler into. If you use a foot pedal, my advice is to set your upslope time to 0, and your downslope to .1 or 0. And just hammer the pedal. Any dillydally will leave you with too much anodize running back into the puddle, and then you'll get too hot, or it won't accept filler. If you try to start too slow, or not hot enough, you won't push out the anodize, and you will melt through without ever getting the surface hot enough to pop the anodize. And, finally, if you have variable frequency, run in the 60-90hz range. If you go up into the higher frequencies, you will not push the anodize aside like you need to. Good luck, go after it again!!!And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Rojo,Thanks for the explanation of the technique.  Do you do anything with the welded area once you're done to make up for the lack of corrosion resistance?  Particularly the towers on a tuna boat, being exposed to the salt air.I r 2 a perfessional
Reply:Same probs on a Jap motorcycle frame/subframe. All crap and bubbles without grinding the anodised away. I'll have a try with that bumping on my spare subframe.
Reply:Originally Posted by SundownIIIDonald,Obviously you've never heard of welding a tuna tower on a boat.  Towers are anodized aluminum and are welded every day.  And yes, they are structural welds and people do stake their lives on the integrity of the welds.Do a search on millerwelds and you'll have it explained for you.Trick is to run hot and run fast.  We use what is referred to as the "bump" technique.Bad advice is worse than no advice.
Reply:Donald,You know of anyone with a vat large enough to anodize a tower on 74' sportfisherman?  Not going to happen.  The welds are painted (alum rustoleum works OK) to minimize oxidation.Check out Pipewelder's website.  They're the largest tower builder in the world, headquartered in Ft. Lauderdale, FL.  The son of the owner is the one who taught me the process they use.  I've described the welding process in detail over on Miller, and provided links to an article done on Pipewelders (about the process).PS  Rojo--- did a good job of briefly describing the "bump" technique for welding anodized alum.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Well here they are... they are not exactly good looking or even... but they are holding... My welding instructor did the first half...  ( Right to left...  and I finished it.. )
Reply:Originally Posted by SundownIIICheck out Pipewelder's website.  They're the largest tower builder in the world, headquartered in Ft. Lauderdale, FL.
Reply:Engloid,Anodization is a chemically induced oxide, but because it is chemically "grown" onto the surface of the metal, it is up to 200 times thicker than the normal oxide you would see on aluminum.  And oxides of aluminum are non-conductive.  I think that's why they're describing having to "bump" the part with no slope.  Not to mention anodize is harder than a hooker's heart.I r 2 a perfessional
Reply:For future reference, if I turn my Syncro250 balance to max clean, would that help?9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Originally Posted by Craig in DenverFor future reference, if I turn my Syncro250 balance to max clean, would that help?
Reply:Originally Posted by smokeshowWell here they are... they are not exactly good looking or even... but they are holding... My welding instructor did the first half...  ( Right to left...  and I finished it.. )
Reply:my friend does anadized all day  every day for a living making tuna towers for multi million dollar sport fishers i can post better pics later
Reply:why would you not sand it off?I would run down the edge with a belt sander or grinder and put a shallow bevel on it.bevel will make niceer penetration and flatter top.the reason they dont prep the joints on tuna towers etc... is simply TIME.  people who do this often have enough experience to do it just fine without taking the time to prep it.if you dont indentd to make a carreer of it, why not just prepare the surface a bit and make it easier?
Reply:#2,ectruded shapes I believe are commonly "Alodine" coated.  which I think is somehow a little bit diffeernt than regular "Anodize"
Reply:Originally Posted by WANNAWELDmy friend does anadized all day  every day for a living making tuna towers for multi million dollar sport fishers i can post better pics later
Reply:how do you make them bigger?
Reply:Dsergison,"Alodine" is a trademark name by Henkel for a chromate conversion coating.  It is typically applied to aluminum for corrosion resistance, and when you want to paint the aluminum.  (Ever try to paint bare aluminum, it can be done, but it aint easy)  All our military aluminum parts get alodine before we paint 'em haze gray.Anodize is an aluminum oxide conversion of the surface of the aluminum.  Basically, it's the reaction of water with aluminum to form aluminum oxide.  No, don't try to just put your part in a tank of water and hope it will anodize.    There's a lot of chemistry and electricity involved and anodes and cathodes and lions and tigers and bears, OH MY!.It's generally used as the final finish on the part, and since it can be died many colors, it takes the place of paint.  Depending on the thickness of the anodize applied, it makes a great wear coating as well, since it's essentially a ceramic.I r 2 a perfessional
Reply:Rojo: The lower setting will clean it better, and the cleaning will help with pushing the anodize out to the sides. If you use too much cleaning, the anodize will jump all over your tungsten, and it will be tough to clean it well, as even once you grind ity again, the stuff on the stem of the tungsten will migrate down to the tip pretty quickly. Rojo: Thanks, Craig kbnit: There's a lot of chemistry and electricity involved and anodes and cathodes and lions and tigers and bears, OH MY! OK, everyone outta my bathtub, I wanna try sumtin'.  9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Originally Posted by dsergisonwhy would you not sand it off?
Reply:Engloid, thanks for the confirmation on both accounts.to clarify, -I dont think the plates he was welding were anodized.  I think they were alodine.I've bought lots of extrusion.  And I dont think any of it has ever been anodized.  I think it's all alodine.     at least, it has a very different look than the parts I have had anodized.  and it doesnt seem nearly as hard either.so, are tuna tower tubes supplied with anodize or alodine?and, if it's chromate conversion, is there any healt risk from welding and chromium?---those tuna tower welds look spectacular.  I'm familiar with painting raw aluminum.  but I'm even more familiar with UNPAINTED raw aluminum.I built this toolholder rack. http://www.sergisonmachine.net/images/toolroomdoor.jpg I flap-disked it to a beautifull swirlly finish, mounted and admired it..   then I set all my tools in it and went to bed.   the next day they had ALL RUSTED!!!!!!!!!!!!     now it's painted black, no more rust problem.  but the paint still chips bad.
Reply:Yes, chromium is an acknowledged cancer agent.  I think it's banned in the entire state of California.......Alodine is not as tenacious as anodize, however, you could clean it off with a powered wire brush in no time.I r 2 a perfessionalThe aluminum is from Kawneer... Aka... ALCOA...  I am 95.9% positive it is anodized...And this was TIG welding... and I had it set a 99.. and I am not that skilled at aluminum welding yet..I just have access to a large quantity of scrap Kawneer aluminum... which is why I chose to use this metal... and I agree I should of did more cleaning...
Reply:Originally Posted by smokeshowThe aluminum is from Kawneer... Aka... ALCOA...  I am 95.9% positive it is anodized...And this was TIG welding... and I had it set a 99.. and I am not that skilled at aluminum welding yet..I just have access to a large quantity of scrap Kawneer aluminum... which is why I chose to use this metal... and I agree I should of did more cleaning...
Reply:I need a good bit of more practice before I feel I would ever attempt welds that would be seen on a daily basis. It is 6" wide and  about the same on the long side.  So I fully agree with you on the surface area absorbing the heat faster/greater than I was using...  And I looked closer today and noticed that the anodizing was mixing in the weld, so the cleaning was not good enough.. ???
Reply:Originally Posted by smokeshowI need a good bit of more practice before I feel I would ever attempt welds that would be seen on a daily basis. It is 6" wide and  about the same on the long side.  So I fully agree with you on the surface area absorbing the heat faster/greater than I was using...  And I looked closer today and noticed that the anodizing was mixing in the weld, so the cleaning was not good enough.. ???
Reply:Originally Posted by RojodiabloIt could be, or you could be not getting enough of a blast to push the anodize out of the way. I get some creeping back onto the weld, that is normal. And, it does no harm, as it is on the surface.
Reply:Rojodiablo, from what you are describing it sounds like this might be a good aplication for pulsed tig if set up properly. I've never used the pulse on my machine, and the only info I've gotten so far was to learn to weld without it before starting to play with pulse as its more of a crutch to help poor welders run beads out of position. Comments?
Reply:Have tried some welding on an anodised Suzuki GSXR750 subframe with my Hitachi 300DG. The HF will pop right through the anodised layer but it didn't get any better than shown in the pictures below. Used soft, hard and hybrid wavevorms and pulsing. On the pictures I used the normal wavevorm (square) with 120/50 Ip/Ib (Pulse/Base) at 20/80% 30% Ep (Electrode positive) and 200Hz.Welds smell like H2S (rotten eggs) and GF looked up the ceiling to spot any pigeons above my welding table. She didn't see any Did some welding earlier on this subframe after removing the anldising which went easy.
Reply:Thanks for the input guys...  I don't have access to a machine till mid July, so it will be a bit before I try it again...
Reply:Originally Posted by dsergisonso, are tuna tower tubes supplied with anodize or alodine?
Reply:Originally Posted by DSWRojodiablo, from what you are describing it sounds like this might be a good aplication for pulsed tig if set up properly. I've never used the pulse on my machine, and the only info I've gotten so far was to learn to weld without it before starting to play with pulse as its more of a crutch to help poor welders run beads out of position. Comments?
Reply:Originally Posted by ElGuapoHave tried some welding on an anodised Suzuki GSXR750 subframe with my Hitachi 300DG. The HF will pop right through the anodised layer but it didn't get any better than shown in the pictures below. Used soft, hard and hybrid wavevorms and pulsing. On the pictures I used the normal wavevorm (square) with 120/50 Ip/Ib (Pulse/Base) at 20/80% 30% Ep (Electrode positive) and 200Hz.Welds smell like H2S (rotten eggs) and GF looked up the ceiling to spot any pigeons above my welding table. She didn't see any Did some welding earlier on this subframe after removing the anldising which went easy.
Reply:Thanks for the comment Rojodiablo, for a moment I thought it might be on my account not being able to use all the possibilities of my welder. So | guess the rotten-egg smell might be caused by the clearcoat because there shouldn't be any sulphuric components in the aluminium.
Reply:Yeah, I never smell sulphur when welding aluminum. Might want to try and carefully scrub a spot clean, and then try to weld it. I think you will get a better result.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Engloid,   I am the employer, and all of the employees. (machnist, welder, book keeper, salesman, floor sweeper.)  -that is my home shop.
Reply:I guess I'll be the one to tease everyone here.1/4" anodized 5052 plate welded to 1" SCH40 anodized tubing. Nasty anodizing on the edges of the weld.Dynasty 350187 amps5356 fillerIf you cannot convince them, confuse them.         Harry S Truman
Reply:Nice welding  pitty bout the anodizing crap.
Reply:Problem is there is no way around it with out removing it, then the problem is you have a bunch of scrtached up tubing. As other have said, we just run over it with Rustoleum "Aluminum" colored paint and it looks more then acceptable. Do you know the grade aluminum the subframes are made from your welding on. I know some alloys are alot harder to weld then others, if not impossible. We work exclusively with 5052 and 6061 So I have no experience with the other stuff.If you cannot convince them, confuse them.         Harry S Truman
Reply:No, I don't have any idea what material the japs use for their frames or motors. Would be great to know though.
Reply:Silverado...Looks good... my welds are nowhere near as good looking... and have much more anodizing in them..  one day  I might be able to do as good as job as you..
Reply:Originally Posted by ElGuapoNo, I don't have any idea what material the japs use for their frames or motors. Would be great to know though.
Reply:Thanx, At first it seems only KTM will reveal the choice of material but I'll wade some more soon.Öhlins adapterplates are made from 7000 series also.
Reply:Most of the bike chassis parts are a 6061 extrusion.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Anodizing is usually thicker than the normal layer of aluminum oxide that forms on the surfaces of bare aluminum.  You can remove the anodizing by soaking the aluminum item in a 5% sodium hydroxide (NaOH) and water solution for a few minutes (Red Devil lye is NaOH).  Do outside in well ventilated area - process generates flammable hydrogen gas.  Wear protective gloves, faceshield, and apron during process. Stop process by removing item from solution and rinsing with plain water and scrubbing residual off with steel wool or scouring pad.  Prolonged soaking will also dissolve pure aluminum under the anodized layer,  so keep an eye on it and soak and rinse in stages.  Greased Lightning spray cleaner also contains NaOH and will also remove anodizing, but gets expensive for anything large.TeddCoHTP Microcut 400 & Invertig 160DC  Smith Dual Guard MD-510 OA Rig  Lincoln SP135+  Hobart Stickmate LX 235/160