welding Anodized alum pipe

[jcoldon]

Welding anodized aluminum
I have welded alum anodized and never cleaned
the process is simply a button on my tig torch
Full amps a puddle rod stop then next puddle rod and so on
This is the pipe welding process for anodized pipe

I use a sink wave 250 ac
All boat tops and towers are anodized either black silver or gold

The process works on all aluminum you will have to clean dirt and grease
Hope this helps

[journeyman]

just wondering how jcoldon accomplishes welding on anodized alum without removing anodized coating. In my experiences with anodized alum I've always seen higher quality finished product when removing anodizing. Doing something different?

[fun4now]

the anodizing is just like any other oxidation, if you have the power to blast threw it and float it out of the way you get a good weld. i have heard pulse can be used to help break up the anodizing but never tried it. just read about it on here.

[SignWave]

I recall way back when in the days of BMX riding, we would remove the anodizing from our bike parts with easy off oven cleaner. Spray it on, let it stand , wipe it off. the AL came out sorta luster and a buffing wheel made it quite glossy.

the active ingredient that made this all possible is sodium hydroxide ( NaOH ). its found in Drano, lye, oven cleaner, some outdoor cleaners and laundry additives...

[HMW]

Like fun4now, I think most tuna tower buiders do not remove it first. I read an article, I believe in Miller magazine, The guys there did not clean it off. I have done only 2 piece's and I removed it. It was for seats in a boat, so didnt take long. But it would take for ever on a whole tuna tower to remove all the anodize on each place it needed welding. If I find some more I'm going to try it.

[fun4now]

hey... are you calling me a tuna tower

LOL i just had to do it.

[HMW]

If the pipe fits...........

[SundownIII]

HMW,

Don't know the OP's background, but basically what he says is right on the money.

The larger marine fabrication shops (ie. Pipewelders) do not remove the anodizing prior to welding. To do so would be too time consuming/non cost effective.

I learned a lot of what I know about marine fabrication from Edison Irvine (good friend of mine who's dad owns Pipewelders). He used to run the Cape May facility for Pipewelders (@ the Canyon Club).

The best writeup I've ever seen on welding anodized aluminum was an expose done by Mike Sammons (product manager, Miller Electric Co.) on how Pipewelders pioneered this process. Article appeared in MetalForming magazine in November 1999. Article was called "Transforming Raw Materials into Reality. I haven't been able to find a link to the article, but, if you're really interested, I'll scan it and e-mail it to you.

Ironically, Pipewelders developed the process using predominately the 330 ABP machines. As those machines reached maturity (ie. wore out) they were replaced by the Syncrowave 350's. I'll have to check with Ed to see how many of the Sync's have now been replaced by Dynasty's (you can bet that whatever the replacements will be, they will be BLUE. Miller and Pipewelders have been in bed together since the beginning).

Let me know if you can't find the article.

PS: After thinking about it I found the link. Try http://archive.metalformingmagazine..../11/miller.pdf

Think you'll find it interesting and informative.

[Bert]

So I guess my Dynasty 200 is underpowered to do it? I'm thining 1-1/2" schedule 40 aluminum "pipe?"
bert

[SundownIII]

Bert,

Haven't used a Dynasty 200 much however I do have a friend with one and it's a sweet package for what it is. It does a great job on aluminum but, due to amp output and duty cycle, it's probably not the best machine for doing a lot of anodized aluminum. That's one of the reasons I, along with several others on this board, have been pushing Miller to come up with an inverter in the 250/275 range. Doesn't have to have all the "bells and whistles" of the Dyn 350, but a little more guts than the Dyn 200.

I run my Sync 250 at about 200-210A when doing this type work. The 200 just won't quite get there. Even with frequency adjustment (increase to narrow the arc) it comes up lacking in the ability to "blast" the oxidizing. Now a buddy of mine who does a lot of anodized fabrication, and used to use a Sync 250, has a Dynasty 300. Runs it at about 196-200A and raves about the machine as compared to the Sync. Duty cycle has never been an issue, since with this type of work, there's always a good deal of fitting/repositioning involved which helps with the duty cycle.

Don't get me wrong, the Dynasty 200 is a great machine and I'd love to own one. It's just that it won't quite replace a Sync 250. Is Miller listening? I think they are, especially since Lincoln just introduced a new 300A inverter.

Regardless, I hope that article put to rest the discussion about having to remove the oxidation prior to welding. I've said it all along, but that article details the process better than anything else I've seen. An experienced welder, using the on/off switch, will make it seem almost like a continuous weld. The foot pedal works well also, but mainly for "bench" type work.

Hope this helps.