aluminum welding

[oldguy44]

I have been welding since I was old enough to wrap my fingers around the torch in my dad's auto repair shop. I have welded up race car frames and did a stint fabricating structural steel but in all my years I have never welded aluminum. More and more I am finding the need and it is getting to be a pain setting things up and having someone else weld them, finding out that it is not quit right and going back to have it modified. I still have a Lincoln DC250 power source with an LN7 wire feed on the top. Lincoln tells me that there are no provisions for adapting a spool gun to the LN7 but years of experience has taught me that Mr. Disney's mouse has ways that manufacturers either do not know or won't share. The DC250 has the capacity to tig weld but apparently does not have a high frequency generator so requires a scratch start. I have also never ventured into TIG. The majority of my experience is stick and MIG. I probably only need to weld aluminum once or twice a year so spending a lot of money does mot make sense. If I can somehow adapt an inexpensive spool gun it will probably meet whatever need I have.

The current project is a dual chambered tank that will need to hold about 20psi. The base material will be 4" square tubing with about an .060 wall. I have to use aluminum because of the corrosion created with dissimilar metals. What about the low temp aluminum soldering rod? Does it work and is it capable of holding 20psi and be liquid tight?

I am open to any suggestions.

[G-ManBart]

I'm not an expert, and I don't know anything about the LN-7, but if you could get some knurled rollers for it and a short whip with a teflon liner you might not need a spool gun at all. The bigger the wire diameter the better for that setup as well, so you'd probably want at least .045 wire. You'd probably have to keep the whip pretty straight and it might not always work perfectly, but for a couple of times a year might not be a bad solution.

[Dean Mott]

You can actually weld aluminum on dc, I’ve seen a couple videos about it on YouTube, just search for weld aluminum dc tig


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[M J D]

You don't want mig for something that thin. In all honesty cut and fit your pieces and take it to someone to weld it up for you with Tig. Adding a high frequency box,( which is necessary for aluminum) will cost more than a new budget AC-DC Tig machine.

[Oscar]

You don't want mig for something that thin. In all honesty cut and fit your pieces and take it to someone to weld it up for you with Tig. Adding a high frequency box,( which is necessary for aluminum) will cost more than a new budget AC-DC Tig machine.

Yup.

0.060" alum = AC TIG or pulsed spray MIG .

[M J D]

[QUOTE=Oscar;8813673]Yup.

0.060" alum = AC TIG or pulsed spray MIG .[/QUOTE
I wouldn't attempt pulsed spray on something that thin that's also a pressure device although pulsed is definitely better than regular mig on thinner stuff. Even on commercially made aluminum tanks which are mig welded, the stops of the welds and bungs are Tig welded.

[Munkul]

I'm not an expert, and I don't know anything about the LN-7, but if you could get some knurled rollers for it and a short whip with a teflon liner you might not need a spool gun at all. The bigger the wire diameter the better for that setup as well, so you'd probably want at least .045 wire. You'd probably have to keep the whip pretty straight and it might not always work perfectly, but for a couple of times a year might not be a bad solution.

You don't use knurled rollers for aluminium, the wire is too soft. The knurls will rip the wire to pieces, and subsequently shred the liner and clog it up with aluminium scrapings.

Instead, U shape rollers are the standard for aluminium. You can sometimes get away with standard V rollers, if you have a really sympathetic feed setup.

The ideal setup for aluminium is a 4 roller feeder with U rolls; a teflon liner right from the feed roll exit all the way to the gun neck; a short brass wire liner down into the gun neck to the tip; and an oversize wire tip. I use 1.2 tip on 1.0mm wire, and a 1.4 tip on 1.2mm wire.

I've set up a few MIG sets like this - a Lincoln 405 at work; my Miller XMT and 64 feeder, and now my fresh Lorch S3 MIG set. No spool guns in sight!
I've even had a dealer set a Lorch up for feeding pure aluminium wire - incredibly soft, some feeders just can't handle it - was a setup as described, with a carbon/teflon liner, a 4m whip, and a watercooled gun. He even tied a knot in the whip to prove that the setup fed nicely.

You can get "A" designated aluminium tips, but I've found these have an even bigger tip, and it doesn't allow pulse MIG to run as smoothly.

[M J D]

You don't use knurled rollers for aluminium, the wire is too soft. The knurls will rip the wire to pieces, and subsequently shred the liner and clog it up with aluminium scrapings.

Instead, U shape rollers are the standard for aluminium. You can sometimes get away with standard V rollers, if you have a really sympathetic feed setup.

The ideal setup for aluminium is a 4 roller feeder with U rolls; a teflon liner right from the feed roll exit all the way to the gun neck; a short brass wire liner down into the gun neck to the tip; and an oversize wire tip. I use 1.2 tip on 1.0mm wire, and a 1.4 tip on 1.2mm wire.

I've set up a few MIG sets like this - a Lincoln 405 at work; my Miller XMT and 64 feeder, and now my fresh Lorch S3 MIG set. No spool guns in sight!
I've even had a dealer set a Lorch up for feeding pure aluminium wire - incredibly soft, some feeders just can't handle it - was a setup as described, with a carbon/teflon liner, a 4m whip, and a watercooled gun. He even tied a knot in the whip to prove that the setup fed nicely.

You can get "A" designated aluminium tips, but I've found these have an even bigger tip, and it doesn't allow pulse MIG to run as smoothly.

I would say your partially correct as far as drive rolls go. On the miller 30A spool gun the drive roll is a knurled V groove roll against an idler bearing. I'm sure that's due to the small diameter and gripping the wire.

[Munkul]

I would say your partially correct as far as drive rolls go. On the miller 30A spool gun the drive roll is a knurled V groove roll against an idler bearing. I'm sure that's due to the small diameter and gripping the wire.

Push-pull and spool guns are a different ball game. They don't have a long soft plastic liner to damage after they've knurled the aluminium, since they only push it a short distance.

Even on a push-pull setup, the push rolls in the wire feeder are U rollers. The pull rollers can be whatever, because it's only pushing the wire through a short section which is usually wire anyway.

By all means you could use knurled rollers to push aluminium through a regular whip I won't say a thing - but you'll be swearing plenty, after the 2nd liner change, and 10th burn back and birdsnest...

[M J D]

Push-pull and spool guns are a different ball game. They don't have a long soft plastic liner to damage after they've knurled the aluminium, since they only push it a short distance.

Even on a push-pull setup, the push rolls in the wire feeder are U rollers. The pull rollers can be whatever, because it's only pushing the wire through a short section which is usually wire anyway.

By all means you could use knurled rollers to push aluminium through a regular whip I won't say a thing - but you'll be swearing plenty, after the 2nd liner change, and 10th burn back and birdsnest...

What I'm getting at is the " tearing aluminum wire up" part. With the tension set correctly it doesn't happen. As for feeding thru a whip, I'm sure your spot on. I've tried it and in all honesty it sucks. Buying a new, shorter gun , rollers and whatever else isn't cheap either. I've used spool guns forever and other than being more bulky they work really well. Either way, for what the OP wants to accomplish, it's the wrong process no matter how you feed the wire.

[shovelon]

What I'm getting at is the " tearing aluminum wire up" part. With the tension set correctly it doesn't happen. As for feeding thru a whip, I'm sure your spot on. I've tried it and in all honesty it sucks. Buying a new, shorter gun , rollers and whatever else isn't cheap either. I've used spool guns forever and other than being more bulky they work really well. Either way, for what the OP wants to accomplish, it's the wrong process no matter how you feed the wire.

That is correct. A "U" groove drive roll pushing alum wire through a short nylon liner works well. Will it work on .06" wall tube? Not very likely. With that said I was approached by an old guy that restores vintage British cars and had bought a Harbor Freight Titanium gas mig with a spool gun. He could not get it to work and the idiot chart was not helping. So I said I would fire it up, tuned it in, and was able to get him to weld .03" body panel sheet with .030" 4043 wire. That is the route I would go before dumping a bunch of money into something that was never designed to weld alum.

[Munkul]

Either way, for what the OP wants to accomplish, it's the wrong process no matter how you feed the wire.

I agree.

I bit at the knurled rollers comment to start with because it was simply incorrect.

[G-ManBart]

You don't use knurled rollers for aluminium, the wire is too soft. The knurls will rip the wire to pieces, and subsequently shred the liner and clog it up with aluminium scrapings.

Instead, U shape rollers are the standard for aluminium. You can sometimes get away with standard V rollers, if you have a really sympathetic feed setup.

You are correct. I was thinking of the knurled rollers on a spool gun. I know better as my 350P uses U rollers on the feeder for aluminum.

I suggested using a short whip with a teflon liner rather than a spool gun not for the current project, but because the OP said he has projects a couple of times per year...no idea if they're all thin aluminum or not. If not it would be a much cheaper solution than a spool gun.

[oldguy44]

Thanks to all for your input. I am now checking with gun/cable suppliers to see if I can find an 8' cable with a teflon liner to fit the LN7. I can increase the wall thickness of the current project without difficulty. It is just a custom radiator catch tank that I need for an engine swap nothing critical. The current tank is plastic so I do not believe that the pressure will be a problem. I believe mig is the least expensive choice. I had a guy weld up a crack on an aluminum oil pan several years ago. He used a mig, welded it in about three minutes and it never leaked a drop.
I will keep checking craigslist, who knows someday I might find a good used tig at a price I am willing (and able) to pay.

[Weldordie]

What about the low temp aluminum soldering rod? Does it work and is it capable of holding 20psi and be liquid tight?

I am open to any suggestions.

I just skimmed over all of the suggestions that were made to help, but didn't see anyone answer the above questions. Based on the equipment you have, I would certainly get ahold of some of the aluminum soldering/brazing rod, and do some experimenting. I suspect you might be surprised at what it will do. I've used it to repair gashes in large irrigation pipe.

[Denis G]

Someone on Ebay is presently selling a Lincoln DC-250 + Airco spoolgun + rolls of 4043 wire:
https://www.ebay.com/itm/Lincoln-Ide...-/274569715868

[T Red]

is it capable of holding 20psi .

.06" aluminum seems thin on 4" square tube even for 20psi. It might push the walls out like a balloon. Round would be better, or thicker.

[BaTu]

OMG!

I can help but think that you'd be So Much Better Served by an inverter Tig Welder for this (and, Really, your future Welding).

For what it costs today, why would anybody go so far Backwards???....

[Munkul]

when we say technically you can mig weld it, what we really mean is, someone some where with a really fancy automated pulse MIG can weld it... but a normal person will struggle.

It's hard enough work to MIG 1/8" or thinner, unless you have a good modern pulse MIG set.

You'll be lucky to get it to work on 060 at all. As said above - you need an AC/DC TIG welder. Ideally a modern inverter.

[M J D]

when we say technically you can mig weld it, what we really mean is, someone some where with a really fancy automated pulse MIG can weld it... but a normal person will struggle.

It's hard enough work to MIG 1/8" or thinner, unless you have a good modern pulse MIG set.

You'll be lucky to get it to work on 060 at all. As said above - you need an AC/DC TIG welder. Ideally a modern inverter.

With aluminum mig you have 3 major things working against you on smaller parts of thinner material. 1 cold starts, preheat can help on that but it only makes the rest harder on smaller items. 2, insanely fast travel speed and high rate of metal deposition. 3, craters that can be problematic for anything sealed , pretty hard to avoid them at the end of the weld, especially on smaller or thinner parts. By backstopping the crater it can be filled but again much more difficult on small items. One of the less than 1,000$ AC-DC inverter Tig machines would make the entire aluminum welding thing worlds easier.

[oldguy44]

I do have a pulse welder, it is called my trigger finger. I have been successfully mig welding thin steel, read auto body, for close to 30 years using .030 and .035 wire without generating enough heat to cause distortion. So if the issue is pulse welding I have been doing it for years. The machine several posts back is the exact machine I have in my garage, now the only question is how did he wire the spool gun. Looks like it was quite a project.

As for the 20psi ballooning .060 4 in. square aluminum tubing custom aluminum radiators are .040 or less. I have two vehicles that have them and they hold just fine. But as I stated way back I am not locked into tubing that thin, I can increase the wall thickness without issue. I just need something that has a relatively small cross section to fit where I need it with around a gallon capacity the tank only needs to be about 14 in. tall.

I plan to go on the search for a short gun and cable that will fit my LN7, seems like a good place to start.

[Oscar]

I do have a pulse welder, it is called my trigger finger. So if the issue is pulse welding I have been doing it for years.

I plan to go on the search for a short gun and cable that will fit my LN7, seems like a good place to start.

What you're describing is more akin to "stitch" or "spot" welding. Pulsed-spray MIG is a completely different animal altogether.

Call up HTP. They sell 8 ft MIG guns for aluminum with carbon graphite liners. They might be able to put a different back-end connector for your LN-7

[oldguy44]

Thanks I will give them a try.

[albrightree]

While your ordering your gun, make sure you pick up a roll of 5356 .035" aluminum wire . You'll get a lot less bird nesting than the 4043 wire, which is much softer. Going to a little bit thicker aluminumb will make your life much easier . Joint design is going to make a big difference too, having a thicker endcap that fits into the tube would make for an easier welding job. Make sure you have plenty of extra material to practice on, its possible to do what you want, but their will be a price in time and material. It still won't look as pretty as a nicely TIG welded job.

Is this work for yourself , a friend, or a customer ?

There are some nice AC/DC Inverter TIG machines out their, if its a business, it might be a good investment.

Best of luck on your project, and let us know how you like your new gun if you get one. I've been thinking of buying an aluminum only MIG gun for my snap-on mig machine from HTP for a while (tweco style)Their prices on wire don't seem to bad either.


Regards

[Denis G]

While your ordering your gun, make sure you pick up a roll of 5356 .035" aluminum wire . You'll get a lot less bird nesting than the 4043 wire, which is much softer. Going to a little bit thicker aluminumb will make your life much easier . Joint design is going to make a big difference too, having a thicker endcap that fits into the tube would make for an easier welding job. Make sure you have plenty of extra material to practice on, its possible to do what you want, but their will be a price in time and material. It still won't look as pretty as a nicely TIG welded job.

Is this work for yourself , a friend, or a customer ?

There are some nice AC/DC Inverter TIG machines out their, if its a business, it might be a good investment.

Best of luck on your project, and let us know how you like your new gun if you get one. I've been thinking of buying an aluminum only MIG gun for my snap-on mig machine from HTP for a while (tweco style)Their prices on wire don't seem to bad either.


Regards

He might want to stick to 4043. Radiator temperatures get close to 200 deg.F and 5356 has magnesium which has corrosion problems at elevated temperatures:
https://www.indalco.com/when-should-...ld-i-use-5356/