Welding Aluminum. How hard can it be?

So, I bought a cheap used aluminum capable MIG welder. It even came with 1/3 a roll of aluminum wire.

Today, I installed a 50 amp 230V receptacle in the shop, changed the machine from 208 to 230, and then spent 45 minutes trying to get it to feed the wire without birdsnesting it. The push-pull arrangement for the wire feed is a little tricky to adjust, to say the least.

The good news is it works. It makes sparks and melts aluminum. It's a little hideous looking without shielding gas, but it made a puddle.

Now what do I need to know. What kind of shielding gas. I've read Argon, but it looks like Tractor Supply only carries Argon/Co2 mix. Can I use that or do I need to source pure Argon?

Is aluminum any harder to weld than steel. Are adjustments similar or is it a whole new process.

Any pointers would be appreciated. I've got a trailer to build.

Aluminum is much harder to weld than steel. You have to change your hand speed to compensate for heat. It melts like butter. You have to have it ridiculously clean. The spool gun has to feed smoothly ... I don't think I'd try to MIG an aluminum trailer together as my first project unless it was a gift for someone I didn't like very much

I'd be tempted to take a class and rent a TIG. It isn't actually easier at all but atleast you can manage the current while you weld to compensate for the heat instead of changing your tempo. If you get the hang of it - it looks a ton better when you are done. And it's a much cleaner process too. No pop and spatter.

Actually, I might be tempted to rent a "TIG guy" if I wanted to have the thing done before Christmas :)

aluminum dissipates heat a lot better than steel, it's definitely more challenging.

Biggest problem I have is the lack of color change in the puddle. Makes it tougher to manage.

I would mig aluminum way before tig. Its far more forgiving.

As others have said, aluminum has a very narrow range where you are getting penetration, but not melting through it. Knowing what I know from TIG welding it, I don't really know how MIG welding aluminum would go. I know it is done, but It seems like you would end up with minimal to no penetration.

Pure argon shielding gas and clean, CLEAN aluminum. Even if it is a brand new piece of aluminum it isn't clean enough. Keep a stainless wire brush that you only use for aluminum welding and brush the surface before you weld. Raw aluminum reacts with the atmosphere and creates a thin oxide layer on the outside. That Aluminum oxide has a melting point of 3600 degrees. The material under the oxide melts at 1220. You have to brush that off

In reply to Huckleberry:

Where's your sense of adventure. I haven't met a tool yet I couldn't master.

I'll do some practicing before I start the actual build. I have enough scrap at the office to build all kinds of stuff.

In reply to Jumper K. Balls:

I've been watching some youtube videos. They mentioned the 3600 degree aluminum oxide melting temp. That was surprising. The videos make it look pretty easy.

This welder also has a lead in setting that speeds up the wire feed rate as the weld progresses. I'm guessing that is the speed change that Huckelberry was talking about. I was wonder what the purpose of that was.

As the piece you are welding absorbs more heat you you have to either move faster or reduce current. That setting is to take advantage of that.

When you TIG a large piece you pin the foot pedal all the way and wait for your puddle to form. When you start adding filler and moving you will still have your pedal all the way. As the piece gets hotter you will start to back off the pedal to maintain your weld. By the end of the weld you could be at 1/4 pedal or less.

In reply to Toyman01:

I was hoping you would start a thread on your new welder!

No info to share though, as I've never tried it.

Novice here, but I have a Tiny bit of Mig, and some Tig experience on Al. +1 on all the above stuff. Acetone to clean, along with aforementioned dedicated Stainless brush. The importance of watching the heat in the metal cannot be overstated. For instance, on a cold morning, it can be hell to get it to wet out. Equally, there is a sweet spot, once the metal is heated nicely, that things go well. Once you notice things not going well, walk away. Once you can hold a bare hand on the last area welded, you should be good to go. There are "junk rods" that will help when Tigging unlike, or dirty aluminum. See if there are junk spools available. I believe there must be.

I've got a never used spool attachment for my Miller I've been dying to try out, but got interested in Tlg first. I very much look forward to following along.

I played around with welding aluminum using my Hobart MIG welder.

Kinda worked OK after I replaced the (old) gun cord with a Teflon inner liner. (maximum bird nesting prior to that change)

If I were to do it again with this welder, I would get a spool gun.

Have FUN!

Rog

I have successfully MIG'ed aluminum with my Italian HF 110V MIG and straight Argon. I would not want to do a large project with it.

My Lincoln has a kit to convert to aluminum Mig welder and I tried it but was unhappy with the results. I bought a Lincoln Square Wave 200 and love Tig welding with it. It's made such a difference to my race car, too. A lot of steel parts have been converted to aluminum

I've only done non-structural MIG welding on aluminum. The most ambitious project to date was an intake air box for a TR6. It was certainly a learning experience. Many of the new words I learned can't be repeated here as I doubt there's a forum filter for them.

I used an older Hobart Handler with 0.030 wire and full argon on 0.050 aluminum. Getting the wire speed, voltage, and gun technique right so that I could lay a clean bead took lots of practice on scraps. Cleanliness definitely helps. I kept birdnesting the wire. Pulling the gun away from the puddle and using faster/wider gun motion seemed to help some with that, but it was still slow going. If I hadn't ground down the welds, I wouldn't have shown the end result. But no air leaks in the end. It can work, but not the easiest way to go.

Thread has my interest. NAPA has a special on for a 110/220 MIG welder with spool gun for around $1000 and welding aluminum would make my life easier.

I've tried gas welding aluminum and by the time I got what I thought was an acceptable weld, I turned the torch off and flipped up my mask and found that I warped/melted the rest of the part. D'oh!

Welding aluminum presents some unique challenges compared to welding steel or other common materials, particularly in terms of the chemistry and crack sensitivity.

In many cases, welding aluminum requires following some special procedures. Important factors when welding the material include: selecting the right filler metal; proper storage and thorough cleaning of the base material; and proper welding techniques.

I did a little aluminum with my Lincoln Weld-Pak 100.  It was too small for a spool gun so birdnesting was a problem.  I ran it with the recommended pure Argon and it was ok as long as the material was less than 1/8" and clean, clean, clean.  It didn't have enough a** for 1/4".  I'm looking now for something in the 175-250 range before trying it again.  Aluminum is counter-intuitive.  Novices try to turn the amps down, but that requires you to go slow and causes overheating.  For both Tig and Mig, aluminum welds better with high amps and fast movement.

I generally don't weld aluminum if I have any alternative, like bolts or using steel or fiberglass.  

Aluminum will humble you quick if your confident with steel. 
 

what helped me when i was starting to use my spool gun on aluminum was being told about aluminum being a spray transfer, not just going at it like steel. Listening for the spray sound helps. But ive been trying to learn TIG too and thats really friggin humbling. Especially on aluminum. 

SmithAlie said:

Welding aluminum presents some unique challenges compared to welding steel or other common materials, particularly in terms of the chemistry and crack sensitivity.

In many cases, welding aluminum requires following some special procedures. Important factors when welding the material include: selecting the right filler metal; proper storage and thorough cleaning of the base material; and proper welding techniques.

Particular reason your first post is in a 3 year old thread?

bluej said:

SmithAlie said:

Welding aluminum presents some unique challenges compared to welding steel or other common materials, particularly in terms of the chemistry and crack sensitivity.

In many cases, welding aluminum requires following some special procedures. Important factors when welding the material include: selecting the right filler metal; proper storage and thorough cleaning of the base material; and proper welding techniques.

Particular reason your first post is in a 3 year old thread?

Spam bot.

Not only in a 3 YO thread, but also their first and only post. 

I've been watching some youtube videos. They mentioned the 3600 degree aluminum oxide melting temp. That was surprising. The videos make it look pretty easy.

This welder also has a lead in setting that speeds up the wire feed rate as the weld progresses. I'm guessing that is the speed change that Huckelberry was talking about. I was wonder what the purpose of that was.

robertstevenbk said:

I've been watching some youtube videos. They mentioned the 3600 degree aluminum oxide melting temp. That was surprising. The videos make it look pretty easy.

This welder also has a lead in setting that speeds up the wire feed rate as the weld progresses. I'm guessing that is the speed change that Huckelberry was talking about. I was wonder what the purpose of that was.

Wow, what an informative post. Thank you so much for copying Toyman01's post from 3 yrs ago. Maybe you should weld your Aluminum canoe while you are a few miles out at sea, in the middle of a hurricane, without a life jacket or welding visor.

Toyman01 said:

bluej said:

SmithAlie said:

Welding aluminum presents some unique challenges compared to welding steel or other common materials, particularly in terms of the chemistry and crack sensitivity.

In many cases, welding aluminum requires following some special procedures. Important factors when welding the material include: selecting the right filler metal; proper storage and thorough cleaning of the base material; and proper welding techniques.

Particular reason your first post is in a 3 year old thread?

Spam bot.

Not only in a 3 YO thread, but also their first and only post. 

 

Spam bot aside, did you ever find any success melting AL?