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.

 

[Gary Fowler]

I would forget about trying to weld that thin wall tubing. It would be pretty hard to weld that with a high frequency TIG rig and a professional aluminum welder. Try the propane brazing wire. I saw a demo on that where the guy welded up a 1/2" diameter hole in coke can and it is stronger than the parent metal also. I dont know if it was the same stuff as the link because I couldnt get it to work. I got price for the brazing wire a while back and it was like $40 per pound but a pound would do a lot of work on that tubing. Search you tube for a video of the newest aluminum brazing video.

 

[Stimw]

I have always used Acetone for cleaning. It dries completely and leaves no residue. Just be careful because it is extremely flameable!!
At a previous job I spent 8 hour shifts welding 4' X 12' X 1/4" aluminum panels bent in U shape relining the floors in 38' Aluminum dump semi trailers that had worn through from gravel hauling. I used a spool gun.
First problem is cleaning, second problem is blocking all wind or even air movement. Both are critical.
You are probably also having problems with feeding, aluminum dosen't push well for any distance. The wire can also be dirty or have oxidation on it.

 

[wired1101]

Another issue could be binding in the tip. The wire expands at a faster rate and to a greater degree that steel wire. This causes the variation in feed rate and the bunching you get. I use an oversize tip when welding aliminium and try to keep the liner as straight as possible.

 

[woodsmith]

Thanks for all the advice.

I have possibly bitten off more then I can chew with this and the brazing rod method may well be the sensible option.

It does seem to be a very 'all or nothing' process and very difficult to get anything consistent. It means I can't risk it on a job as getting it wrong ruins the whole project.

The wire is 0.8mm and the tip is 1.2mm I can switch to 1.5mm but I was finding that I was getting the wire melting at the threaded end of the tip.

I shall try some DuraWeld rods, I think they are similar to the Alumiweld stuff but I can get a starter pack of the DuraWeld rod on Ebay uk.

I guess I should put my welder back to steel welding and hope I haven't messed it up. Changing to a teflon liner seems to have lead to gas leaks and a faulty solenoid valve that won't shut off. I have probably lost most of my mini bottle of Argon now so can't really do much more with it.

Guess I'll use the wire for baling drinks cans!

 

[tcartwri]

I have seen some guys do a beautiful job gas welding Al. Something to consider.

 

[rhett]

Hi, to help stop the wire from 'birdnesting - fouling' use the next size larger gun tip. It really does help, if you notice the wire expands and binds in the tip stopping the wire feed resulting in a mess at the rollers. I actually use a Oxy/Acet tip cleaner to slightly enlarge the tip diameter.

 

[swines]

I have welded aluminum with my MIG and then with a TIG. No contest in weld ease and final weld product - TIG because of the AC cleaning action and heat control. What everyone else has said - and then I'm going to add one more. Increase the flow rate of the argon. The blackened welds are most likely because you've lost the shield, and you're incorporating carbon from the carbon dioxide in the air. If not from that - then the aluminum was not cleaned properly. But, even with a TIG, I use a larger cup and a little more gas flow for aluminum.

1. Clean the weld surfaces with acetone before you brush them. This will get contamination off of the metal and you won't brush it into the metal surface.
2. Brush with a stainless brush dedicated for aluminum.
3. Wipe the surface again with acetone using a clean paper towel.
4. Weld immediately after cleaning.
5. Increase the flow rate on the argon.

 

[yomax4]

By looking at your pic's..You are not that far off. Like stated above, You need to learn on thicker material 1/8 or so. Keep the gun straight, tension only as tight as needed and practice. Your welds look like most 1st attempts. You will likely never be able to do a perfect job and that's why they make Tig units, Spool Guns, Push Pull and Twin Pulse Synergic options..

 

[Hooked_on_HP]

You didn't say what wire you were using. If you are trying 4043 give up. It is to soft to push through a liner and if you tighten up the rollers it will flatten it causing more problens at the tip.. You need 5356 wire. This is a stiffer wire.You have to run the 5356 a little hotter than the 4043. I still don't think you will have sucess welding tubing that thin. But you will be able to weld thicker aluminum if you ever need to. About the only way to mig weld somthing that thin is with a pulse machine. Even with my spool gun I can only do a good job of welding material .080 or thicker.
Bill

 

[Shield Arc]

I didn't read every word in this thread, so forgive me if this has already been mentioned!
I sort of remember trying to do this years ago, (30) before buying my first Tig welder. I had a Miller S32S remote wire feeder that I ran on my 450-amp diesel drive. I bought the shortest Mig gun I could get, with a nylon liner, U-groove drive rolls for the feeder, and hung the feeder above the work, so gravity could help me. Had to keep the Mig gun as straight as possible at all times, or I'd spend the next 5-minutes cutting the bird's nest out of the drive rolls. It can be done, but what a PITA!

Here is a couple pictures of a 1/16th inch corner joint I did when I first got my spool gun. I'd still rather use Tig! I never have been comfortable welding thin material, even to this day 3/8 inch is about my limit!