anodized aluminum welding

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I am interested in fabricating and welding a t-top for my boat out of anodized aluminum pipe.  I have seen the tuna towers and t-tops and im looking for some info on the anodized aluminum pipe.  can u buy the pipe already anodized, and can it be bent without cracking the anodize coating.  do they anodize the welds after they are built and welded or are they just buffed and polished to acheive the same shiny look as the anodized pipe.  any info anyone may have on anodized welding of aluminum pipe will be very helpful.........thank you
Reply:i always did the work first then sent the pieces out to be anodized. even the welds are anodized
Reply:not...........jim...if anyone needs help........let me know........jimwww.arctekmarine.com
Reply:hrdhatdivr has nailed it solid. The subtle difference in anodized material and a painted/coated material is tha anodizing is an electro-chemical process that reaches into the skin of the material. And anodizing is not a process you can do with off the shelf supplies or generally at home. You could buy anodized material but would have to grind it off completely to do the tig/welding. There goes your intent of the superior coating down the tubes.
Reply:Your welding wire has to be the same as the metal you are using or the welds will anodize a different shade then the tubing.  Also check with your local anodizer to make sure what size his tanks are.  Most companies have different size tanks.  Of the three anodizers near me only one could handle a 48" x 84" x 3.5" sign
Reply:sandy, not true....you do not have to grind............sorry...........jimwww.arctekmarine.com
Reply:Originally Posted by arc-tek marinesandy, not true....you do not have to grind............sorry...........jim
Reply:no disrespect....yep its what im sayin........jimwww.arctekmarine.com
Reply:My company fabricates, among other things, anodized aluminum store front sliding doors (think, Wal-Mart) and some of the heavy duty doors have to be tig welded where the stiles and rails meet.   I have to add a note to the fabrication drawings to remove the anodize at the dimensions where the welds are to be.   To save a step, we tried to "burn" through the anodize with the TIG torch, but it took way too long.   We also tried MIG welding through the anodize and in the words of my lead welder, "it looked like poop".  That said, the S.O.P. in this aluminum fabrication shop is to remove the anodize prior to welding.There are no small projects
Reply:chk out  www.arctekmarine.com go under button  tig welding...   tell me the gold holder with the tig weld looks bad...no grinding.!!!!   over 4000 structures, not a single grind. .......and its pretty fast...jim www.arctekmarine.com
Reply:arc-tek, You're right, the weld looks good.    It looks like that weld was done on R5 (bright dip) anodize.   Do you also TIG on R1 (satin finish) anodize?      Also, do you know what thickness the coating is, 201, 202, 204 etc?    I'm thinking I might suggest we make another run at welding on anodize.Back when we 1st suggested welding through the anodize, our customer shared their reason for not doing it.   "Anodizing is a controlled coating of aluminum oxide (Al2O3).   Unless you remove the Al2O3 prior to welding, the oxides are trapped in the weld bead and form a weaker weld than if the metal was mill finish to begin with."There are no small projects
Reply:hi, we use a bump button. machine at 200 amps  200 at the torch ..dont know the thickness..also tig brushed finish...hard to learn...had acomplished mill aluminum tig welders apply take a shot ad fall flat on there face.......tricky..5356 filler..pure/zirtung...argon straight..jim  own a millermatic 250 2 syncro 250 and portable enclosed miller trailblazer 302 hf251.coolmate 4 diamondback 350..all seem to have there own sweet spot...jimwww.arctekmarine.com
Reply:Arc-tek's weld does look very nice, but imagineer is correct in that it is best practice, for the highest quality weld integrity, to remove surface oxide just prior to GTAW.  Some applications may not require it, and if you think that welding through a thick aluminum oxide layer won't affect your product, you can save money by not stainless steel wire brushing, and why bother with the the cleaning action of AC or the adjustable AC balance power supplies.  I  hope you properly prepared your aluminum hang glider prior to welding. Ideally, weld then anodize.  Note as dnrtheil mentions, 4043 filler metal will give a contrasting dark grey weld due to it's silicon content, 5356 filler will give a better anodized match.
Reply:it is pulser..but very time consuming...also your 1/2 complete on a 25,000.00 dollar tower.and you slip grinding.you just ruined a tower..the boat owner dont want to hear it...jimwww.arctekmarine.com
Reply:Originally Posted by arc-tek marine no disrespect....yep its what im sayin........jim
Reply:Well since I have nothing vested in whether anyone really cleans their aluminum or not before mig welding or tig welding or any welding, I can throw in some discussion without any consequence.Aluminum oxidizes. This oxidation serves the aluminum well. Once this protective layer is formed it helps protect it from further oxidation. Anodizing is (over simplified) a man made aluminum oxide skin better than nature can do it. As much as a thousand times better if you believe the glossy brochure the folks doing the treating pump out.  So if you were to advize someone new as to how to weld any aluminum by whatever process to clean their material before proceeding, then it also makes sense to advize them to remove the anodized layer before welding anodized aluminum. If you wouldn't advise them to clean the anodizing off, then I guess there is no need to worry about a teeny little gray layer that comes with any aluminum that's been setting around awhile.I do realize that it is a common practice amongst those doing towers and T-tops not to remove the anodizing. It obviously works well. These folks seem to make a good living at it. Doesn't matter to me.I think it is, like many things, the difference of what you should do and what you absolutely need to do. I personally weld right through rust, paint and dirt on occassion. If anyones asks how to weld rusted, dirty, painted steel, my advise is going to be to clean it up first.
Reply:pulse myself with bump switch sandy......jimwww.arctekmarine.com
Reply:ok ill quit  ...www.arctekmarine.com
Reply:sandy, would luv to see how its done...ill fly you out to the east coast...show me the way my friend.........happy holidays.........jimwww.arctekmarine.com
Reply:Originally Posted by arc-tek marine pulse myself with bump switch sandy......jim
Reply:Originally Posted by arc-tek marinesandy, would luv to see how its done...ill fly you out to the east coast...show me the way my friend.........happy holidays.........jim
Reply:lol..........jimwww.arctekmarine.com
Reply:Originally Posted by arc-tek marinechk out  www.arctekmarine.com go under button  tig welding...   tell me the gold holder with the tig weld looks bad...no grinding.!!!!   over 4000 structures, not a single grind. .......and its pretty fast...jim
Reply:It's alive! This thread is 2 years old BWS, plus the poster hasn't logged in since Nov. 2006. You'd be better off sending him an e-mail. John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Yeah...saw that after I posted so I went to his website and sent him a note there.  Thanks.Haha...no problem. John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com