Mig welding aluminium

[woodsmith]

I have a Cebora Boxer 155 mig welder that I have been using to weld steel and it has been faultless.

I have just bought a mini bottle of Argon, a teflon liner and a small spool of aluminium wire as I would like to be able to weld some small aluminium parts, mainly thin wall tube from old tent poles to make bicycle trailers.
To date I have been using pop rivets and epoxy glue but could do with welding some parts.

First attempts have been hit and miss, either melting the tube away completely or just blobbing on the surface. The welds around the melted tube has been smooth and shiny but the blobs have been cratered and rough looking. Not getting much in between.
Should I have more power lower wire speed or less power higher wire speed or something else?
I only have 7 power settings and a wire speed dial.

Any advice or tips to help me progress further in my trail runs please?
If I can get a nice consistent bead run then I can work on it from there until I improve enough to actually join bits together.

If this works then I will invest in a larger gas bottle but I don't need it enough to invest in TIG right now.

Thank you.

 

[woodsmith]

Here is a photo of what I have managed to do so far.

The blobby black bits are the first attempts.
There is one acceptable weld, the upper of the two tube joints. The lower one is cratered and porous.

I can't seem to get a consistent weld as the wire burns back, jams, bunches up and sticks despite careful setting up. Sometimes it doesn't bunch with a good bit of roller pressure, other times, it bunches up even when the rollers have a lot of slip.

Also when the feed is working, and the settings are the same, some welds are so hot that the tube melts away suddenly, other times the weld bead just sits on the surface.

Given it can do a good weld, twice, what do I need to do to try and keep that consistency and not get wire jams and too hot/cold welds?

 

[tcartwri]

Can't see the pictures at work, but most people purchase a spool gun for aluminum welding, and even then it will never be as pretty as a tig machine.

 

[ericher69]

Question; did you clean the work pieces with a dedicated (aluminum) stainless brush or us an acid etcher cleaning fluid?



Preweld cleaning requires two operations: oil/grease removal and oxide removal. As below, remove oils and greases first, then remove the oxide. Don’t reverse this order.

Take the following steps before welding aluminum:

1. Remove oil, grease, and water vapor using an organic solvent such as acetone or a mild alkaline solution like a strong soap. You may also use citrus-based degreasers, but be sure to rinse and dry the part before welding.
2. Remove surface oxides with a stainless steel wire brush (used only for aluminum) or strong alkaline or acid. Many welding suppliers sell oxide-removal solutions in spray or squeeze bottles for local application. Exercise extreme care when handling these solutions, and again, rinse and dry the part before welding.

3. Assemble the joint. If it won't be welded immediately, cover the joint with brown Kraft paper to prevent dirt and grit in the air from getting into the joint.

4. Keep the aluminum dry and at room temperature.

5. Weld within a few days. Clean the joint again if it isn't welded within that time.

Hope this helps!

What thickness are you trying to weld? 1/16-1/8?

 

[ray66v]

I decided not to even try using my mig on aluminum.

They say the temperature difference between welding, and melting it all away is only like 500 degrees.

The tig welder gives you a lot more control over the heat.

I just use these, when I need to bond aluminum. Aluminum repair kits, repair any aluminum metal by welding with a Propane Torch - Alumiweld

 

[woodsmith]

Thank you for you responses.

Question; did you clean the work pieces with a dedicated (aluminum) stainless brush or us an acid etcher cleaning fluid?



Preweld cleaning requires two operations: oil/grease removal and oxide removal. As below, remove oils and greases first, then remove the oxide. Don’t reverse this order.

Take the following steps before welding aluminum:

1. Remove oil, grease, and water vapor using an organic solvent such as acetone or a mild alkaline solution like a strong soap. You may also use citrus-based degreasers, but be sure to rinse and dry the part before welding.
2. Remove surface oxides with a stainless steel wire brush (used only for aluminum) or strong alkaline or acid. Many welding suppliers sell oxide-removal solutions in spray or squeeze bottles for local application. Exercise extreme care when handling these solutions, and again, rinse and dry the part before welding.

Hope this helps!

What thickness are you trying to weld? 1/16-1/8?

I didn't degrease, just scoured the surface with a fresh stainless steel scouring pad. Getting the wire brush tomorrow I think. I will look at getting some degreaser too.

The tube is 20mm by 1mm thick wall.

I decided not to even try using my mig on aluminum.

They say the temperature difference between welding, and melting it all away is only like 500 degrees.

The tig welder gives you a lot more control over the heat.

I just use these, when I need to bond aluminum. Aluminum repair kits, repair any aluminum metal by welding with a Propane Torch - Alumiweld

I figured that for the small cost of the stuff it would be worth a try. If it worked then I would get a spool gun and modify the welder to be able to switch from steel to aluminium with two gas bottles and two guns.

If it doesn't work then I will have learnt from it and find a different option. That link looks interesting, and easier.:thumbsup:

TIG isn't an option, unless it earns enough money to pay for itself but there isn't enough work to justify it yet.

 

[ray66v]

Clean it 6 different ways. Even the slightest amount of contamination, especially with aluminum, can cause a poor quality weld.

One automotive aluminum welding class I took said, if it's been more than 60 seconds since you cleaned it, aluminum can already start to corrode.

I could never justify a tig welder, especially with a friend that has a fab shop, and will do stuff for me anytime I need.

 

[LD1]

Welding aluminum that thin is very trickey with a mig.

For starters, what diameter wire are you trying to run? You need some small wire for only 1mm thick tube.

Also, tubing by nature is hard to weld, because there isnt much difference in the heat needed for a good weld, and the heat it takes to totally collapse in on itself.

Also, as others mentioned, CLEAN CLEAN CLEAN. You have to make it extra clean with mig. Tig welders use AC which cleans by nature as well as putting less heat into the work.

Mig welding thin aluminum on DC is hit and miss and probabally one of the most difficult things to accomplish. Now if you were working with 1/8" or so material, it is alot easier. But 1mm (.040") is going to be tough for sure.

 

[Chilly807]

What the other guys have said... is true. I have a basic spool gun that came with my Miller 180 and it does an acceptable job, though it's not pretty. Be sure to push the gun, not pull it, you want the shielding gas out in front with aluminum. I had better luck with a longer stickout than I use for steel, too close and the wire melted inside the tip.

1mm is very thin, try some thicker stock to practice until you get better results, then work your way down. Aluminum is touchy stuff, the melting point is very sudden, and not far above the point where it welds smoothly. You can pre-heat with a torch, it helps drive moisture out of the metal before the weld starts.

Sean

 

[LD1]

We had a pretty decent set-up at work. SP-30a spool gun with a miller 350p welder. I hated it. Welding aluminum was hit and miss at best. So I understand the frustration with a smaller unit, and trying to weld really thin stuff. Fortunatally, we talked them into a 200a dynasty Tig. But that is a big company with deep pockets

I know anything is possible with enough practice, but 1mm stock is a tall order with the setup you have.

I agree with Sean, try practicing on some 1/8" stuff and see where that takes you. Maybe you can get it to dial down and get good results. But it is going to take time and practice. You dont learn to weld aluminum (with any quality) overnight.