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Options for welding aluminum, Spool Gun vs Tig ve OA vs... bubblegum?

Parkerbender

Stainless
Joined
Dec 19, 2009
Location
Kansas City Mo, USA
Okay, I have a bunch of canisters to (hopefully) make, and they are just 6"OD tube, 1/8" wall, round lasered end caps, and round lasered flanges, they can be however thick I want to make them-ish (.125, .1875, maybe even .25 if I wanted, but why). If I had 100 or so of these to do every other month, how would we want to do these? They don't see more than maybe 40ish psi, but they cant have any pinholes or anything, so am I out of luck on the spoolgun? I have no experience with anything but Tig, but our Tig welder is getting a little tired, so if we end up getting this I am most likely going to get a new welder regardless of which direction we go. The kid doing this is pretty good at Mig and OA already, he was Mig welding apartment balconies all last year, and before that had a fair amount of practice on OA in school... I am assuming Tig would be the 'standard procedure' to do something like this, but I think they use spool guns on aluminum tanker trailers, so I have no idea...

Thoughts, opinions?

Thanks!
-Parker
 
I don't have a TIG welder so I don't really have a choice. I also don't weld a lot of AL but do on occasions. I have had very good luck with my spool gun. It takes a while to get the wire feed, gas and current adjusted but once you do it goes really well. I would personally be hard pressed to weld very thin AL with my spool gun (less then 1/16") which would be easy with a TIG. Most of what I weld is 1/2" AL plate and I get full penetration with one pass if I bevel one side. One thing I like about the spool gun is that once you get a rhythm going you don't have to stop.
 
Just for the sake of historical interest and completeness, I will add stick welding to your list. In 1958, I had a class in introductory welding. The lab work gave us experience actually doing welding with equipment commonly in use at the time. We were set in a booth with an arc welder, a mask, coated aluminum sticks and two plates of aluminum. The only thing I remember about the job was that you had to travel that stick really fast to avoid melting an inch-wide hole in the plate. It did work, but I would not recommend trying it.

Sounds like that tube and cap job would go easier with a motorized variable speed work head with a foot control.

Larry
 
If the weldor is skilled, tig is going to be just as fast as mig, and when you are finished, the part is done. With mig, there will be cleanup, and, often, touchup welding at the start/stop, or grinding off of big ugly globs.
I have owned a spoolgun, a pushpull, and three tig machines. Spoolgun is a cheap solution that doesnt work that well, jams often, and is big and clunky. The only advantage is price. Push Pull is great- for high production, where looks are not number one priority. A decent push pull, with power supply, can run close to ten grand.
Tig is just as fast, easier to see what you are doing, and if you know how to tig, it comes out right the first time, every time.
Tig it.
 
IMHO forget the process for a second and get some kinda weld lathe - rotary position-er, the job will go way faster if your not having to manually turn the piece.

Im a fan of TIG so am biased, but mig and leak free is doable, just takes more skill and oftern more clean up. That said, some of the newer migs with there pulse capabilities are spose to be near just as good for alu. Hence may be well worth looking into and getting some samples ran if you have a decent welding supply place near by, before just buying a Tig.
 
I am not a welder, don't even play one on TV, but the best looking aluminum weld I ever did was on 06 sheet I welded into a tank,all edges so you can actually get heat into it, it acts 'normal' [IOW like steel]

If you can set up some kind of rotary device it would be super easy
 
If the weldor is skilled, tig is going to be just as fast as mig, and when you are finished, the part is done. With mig, there will be cleanup, and, often, touchup welding at the start/stop, or grinding off of big ugly globs.
I have owned a spoolgun, a pushpull, and three tig machines. Spoolgun is a cheap solution that doesnt work that well, jams often, and is big and clunky. The only advantage is price. Push Pull is great- for high production, where looks are not number one priority. A decent push pull, with power supply, can run close to ten grand.
Tig is just as fast, easier to see what you are doing, and if you know how to tig, it comes out right the first time, every time.
Tig it.

There is no way, except on trivially small jobs with very high appearance requirements, that TIG is as fast as MIG, regardless of material.

The ship building companies around here use MIG for their aluminium welding. I use MIG for steel except stainless pipe work when I use TIG to better guarantee penetration for pressure work. If I don't care that much I still use MIG with 316 wire.

Ries, I have a lot of respect for your opinions & advice as a rule, but here I simply cannot accept what you're saying. It may apply in detailed architectural metalwork, I can see that, but in general, absolutely no way.

FWIW I got my welding tickets in OA, MIG, TIG and stick welding 30 years ago and the *LAST* process I'd recommend is OA - I still remember having to butt weld 1.2mm aluminium with OA and it's not a pleasant memory. I'd use MIG myself, yes there will be a bit of cleanup but if all edges are accessible as they are with a cap on a pipe/tube, a linisher will deal with that issue fast. TIG would be neater and give better control over penetration.

You pays your money and you takes your pick.....

PDW
 
I'd say part of the gearing up proces should also include some powered stainless steel wire brushing machinery.

I hate grinding weld "splash" and I have had really good results with tig on everything I've ever made for interfacing with leak testing machinery....in other words with tig you can visualize the metal flow really well and know its going to be right....or its time to stop and regroup :)
 
All the shipyards around here use pulsed mig too- in fact, a bunch of my former employees have worked in em, doing just that- at least one of my guys still is.
But they build boats out of 30' long pieces of 1/4" plate, where you run 30 foot long beads. And, lots of the time, thicker stuff.

I still say, for a 6" OD Circle, if you include cleanup, I am gonna beat the mig gun in terms of time, and get uniform good penetration and no pinholes. A motorized rotary would make either process a lot faster, for sure. But, really 100 isnt that many- a good weldor can knock out 200 of these welds in a day, which is 100 at each end.
Tig on aluminum likes lots of amps, though- I would want a 250 or 300 amp machine to do this easily and quickly, with a reasonable duty cycle percentage. A cheap machine with a 20% duty cycle is gonna drive you crazy, either tig or mig.
With mig though, you would want a push pull. And cost wise, a push pull is a lot of money- the miller XRs now run about $3500, without the welding power supply. You can buy a pretty nice tig machine for that much.
 
For 1/8" thick I'd Tig it, nice clean job. Clamp it on a rotary and go.
Gotta have a water cooled torch and enough amps/duty cycle indeed.
 
2nd the pulse mig, done right there isn't cleanup
investment will be more than adding or tweaking your current tig setup, but they do make nice welds once parameters are tweaked

mig or tig, prep cleaning is key

still would want to invest in a positioner of some sorts

I'd stick with 1/8" on your end caps.
Joint style whether you insert the cap in the tube or lay it on top will dictate the appearance of the finished weld
 
Using a rotary positioner is key.
As a reference point I can tig that thickness of aluiminum at about 7-8 inches per minute and
have it look good. I have used a Miller 350 with pulse and once it's set up can double that rate, easy.
I don't own the Miller and don't have much time on it but suspect I could get quicker with out trying to hard.
The machine is able to go faster if the weldor can handle it.
I'd look at what else I needed a welder for before dumping maybe $7000 into the mig.....have to build
a shitload of tanks to pay for it.
I'd guess maybe 4 minutes per tank with a tig and positioner, if you could just drop the ends on and go.
David
 
If I had no equipment I would rather buy a big old tig (ab/bf miller) and a positioner. I'd tack all the caps on and then plunk in the headphones and put on the thick glove to keep my fingers comfy.

I hate migs in AL in every possible way.
 
As others have said mig in aluminum is hot and very fast, ok it was 20 years ago :codger:, fortunately I have never run anything but half inch plate but it is still fast no lingering around. My 2 cents, tig with a rotary positioner will probably give the best result. Now that I have a pacemaker :angry: and have to avoid the EMF, my welding days are over Damm!t. That was the loss of the can you fix it biz out of the home shop. :angry:

Scott
 
If I had no equipment I would rather buy a big old tig (ab/bf miller) and a positioner. I'd tack all the caps on and then plunk in the headphones and put on the thick glove to keep my fingers comfy.

I hate migs in AL in every possible way.

Oddly enough in the light of my prior comments, so do I. Even moreso as I had a weldor, ex-Austal Shipping, working for me at one point. That bastard could do prettier welds with the MIG than I could manage with the fancy TIG rig, and much, much faster as well.

I just got him to do all the welding, not being stupid. I wasn't bad, but he was so much better it wasn't worth my time trying.

Agree about the amps. We had a 300A @ 60% duty cycle TIG rig but rarely welded anything over 10mm, probably nearly all was 6mm or less. These days I've got a 250A @ 60% duty cycle MIG and a spool gun but can't remember the last time I welded aluminium.

PDW
 
I'm thinking the people here who are down on the mig for this application have not ran one
of the latest generation units. With correct setup they really do work well.
Only real drawback is initial cost.
David
 
I'm thinking the people here who are down on the mig for this application have not ran one
of the latest generation units. With correct setup they really do work well.
Only real drawback is initial cost.
David

I am thinking you couldnt make the weld (os corner 1/8 th common start stop no leaks or cold lap) with a magic wire gun.
 








 
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