Question for the welders in da house

[Hoosier Daddy]

Yesteday I learned TIG (Heliarc) welding isn't as easy at it looks. :
I learned to used a torch set years ago, and it's still my favorite. I can even weld with a coat hanger for filler rod in a pinch... then came stick welding, then finally MIG. I bought a 120v MIG and can do pretty good with that for home projects considering I am using the flux core wire without argon here.
Yesterday I took my aluminum seat pan to work and tried to TIG, practiced on a piece of scrap till it looked nice then proceded to duck shit on my seat pan, Got frustrated and walked away 3 times, wound up settling for what I will call tack welds in 3 spots just to hold it together. Actually never flowed, like it wasn't hot enough, but I kept turning up the power and stepping on the pedal harder to the point I was afraid of blowing a hole in my nice set pan. Lets just say I am too embarased to post a pic of the results even after grinding the crap off.
Now the question. While looking for some smaller tungsten electrodes at the local Farm store, I saw some "Aluminum Brazing Rod" in the torch section, and a spool of aluminum wire in the MIG section.
Can I weld aluminum with a torch set? How about using my MIG if I buy the regulator I need to hook up an argon tank?
I thought you had to TIG aluminum....

 

[chrisf]

You can MIG aluminum, but it is a pain in the ass. You have to get an aluminum spool gun which is a little pricy or a teflon liner for your current gun.

FWIW, I used to have trouble TIGing aluminum as well. It sounds like you don't have the gas turned up enough. Are you using a gas lens? I find it easier to use them and they only cost like $20 for the whole conversion.

Then again, it could be any number of things like a contaminated electrode, wrong electrode, dirty material....the list goes on.

--Chris

 

[mixmaster]

Electric welding aluminum takes a different Voltage (dc vs ac). Gas welding Aluminum is the hardest i ever TRYED!! I watched those guys at state fairs and expos weld beer cans and such. OMG, i wasted all the supplys and money in an instant. Aluminum welds best if you take a knife and scrape the top layer off make it shinny clean,, and use a wire feed. It's all about heat control, and practice. I had a pedal type mig-tig for years and converted to thumb controls. What a great advancement. And that flux core you are welding with,, it is not as strong as it looks. You do not get penetration like a gas shielded weld. Do not bet you're life on it. And remember, brazeing is just glueing things togather, like soldier. Hope i hepled..

 

[chrisf]

That's a good point. You are welding the aluminum on AC, right?

--Chris

 

[Hoosier Daddy]

You can MIG aluminum, but it is a pain in the ass. You have to get an aluminum spool gun which is a little pricy or a teflon liner for your current gun.

FWIW, I used to have trouble TIGing aluminum as well. It sounds like you don't have the gas turned up enough. Are you using a gas lens? I find it easier to use them and they only cost like $20 for the whole conversion.

Then again, it could be any number of things like a contaminated electrode, wrong electrode, dirty material....the list goes on.

--Chris

Oh, oh... Gas Lens?
Used a fine green electrode..

Aluminum welds best if you take a knife and scrape the top layer off make it shinny clean.

I used a die grinder with a scotch-bite pad on the seams to get it clean, just like all my welds. Good points about the flux core wire and the brazing... I was just explaining my level of experiance.

That's a good point. You are welding the aluminum on AC, right?

--Chris

Yep, had it set on A/C. here is more to the story... I went into work early and had one of my 3rd shift guys who is pretty good at it set up ther welder and show me how it's done. He watched over my shoulder as I practiced on the scrap piece of the same aluminum I made the pan out of. Practice looked pretty darn good, he said I'd do fine then it was time for him to go home (he actually stayed over a while with me.)
I set it down, didn't touch a thing on the welder. Then at lunch I thought I could bang out the seat in an hour.... WRONG.
Now my home MIG is D/C only... so thats out even with a spool gun?

I watched those guys at state fairs and expos weld beer cans and such. OMG, i wasted all the supplys and money in an instant.

They sure do make it look easy don't they!

 

[Firestarter]

Without seeing the weld results I cant tell you what you were doing wrong. However here are a couple of things I have seen give people trouble with aluminum:

Contaminaton- aluminum welding has to be clean clean clean, A scotchbrite disc works fine, but then you need to wipe it down with laquer thinner, because the disc will push crfap into the metal and it will go badly for you when you try and weld it.

Some alloys are different to weld. I once got ahold of some strange marine aluminum that was sent in by mistake, and it would NOT weld for crap to anything else. I ended up throwing it out and making a new piece.

The more I think on it the more I think heat was your issue. A seatpan is a fairly large piece and needs a lot more heat than a smaller thinner sheet. When welding aluminum you are literally taking it to the point of blowing through and using a lot more filler than you would with say, steel. Because of the heat transfer properties on a larger piece of aluminum you will need some patience to allow the heat to come up, and use more heat than you think you need. Once again however its not that simple, because too much heat will cause the aluminum to crystalize and become brittle.

 

[rockcitycafe]

aluminum sheet metal- tig setup

you probably used 3003 alloy for the seat-1100 rod if you're polishing, it's the same color, 4043 if you're not, it's stronger and doesn't want to crack as much

green tungsten, 3/32 usually, same diameter rod

amperage - for 16-14ga, use 100-150, 4.7 duty cycle, 15cfh argon

as far as cleaning, run the edge of a utility knife down the edge of your pieces, works nice and doesn't leave abrasive bits on it

if you're butt welding, clamp a piece of aluminum behind the weld, it will help avoid burn through and give better side penetration in the base material

and you can weld aluminum with a torch, it's not as hard as it sounds but it is tricky with a big welding tip, the first time I did it, I used a jeweler's torch setup, if I were to do it again with my big tanks, I'd have to go with a different regulator, but it's cheaper than tig if you don't have a tig unit

 

[Hoosier Daddy]

Thanks for all the replies... if I had to guess, I'd say you all are spot-on with not enough heat as it really never flowed. Guess we'll chalk this up to experiance (or lack of it). Obviously I would have a rough go of it with my little home MIG unit, more than just buying a tank of argon & putting aluminum wire in it. I will check Monday and see what the smallest brazing tip we have on the torch set at work is and ask for advise on that.
Maybe for now I should just check with guys I know around town who are welders and see if any would do it for a 6-pack.

 

[Basement rat]

Im told what the old timers did back in the air force was more of a braze than weld ???

Also do what you can to clamp what your working with so you have a little space for your filler. If not your work piece will suck togther when it gets hot and your penetration will suck.

I learned to TIG with stainless. Very easy compared to Aluminum.

 

[4eyes]

I woudn't claim to be a welder, but if it welded good at work, and the same settings sucked at home, I'm thinking electrical supply is funky. I've had it happen with my mig. Looked like a hogs ass sewed-up with barbed wire. ;D

 

[beater]

also - do not use aluminum oxide sandpaper or pads, as it leave a residue which prevents puddles forming.

a common technique is to pre-heat aluminum as well as sometimes using your filler to start the puddle. If you are fillet welding aluminum, you will need to make sure you have a nice ball on your electrode as well as have a good sized protrusion, usually 20% more than aperature of the lens.

oxy fuel with aluminum is a challenge, you will find it brazed more often than not. Usually with lugs on frame materials.

 

[Hoosier Daddy]

I woudn't claim to be a welder, but if it welded good at work, and the same settings sucked at home, I'm thinking electrical supply is funky. I've had it happen with my mig. Looked like a hogs ass sewed-up with barbed wire. ;D

Sorry I wasn't clear on that, I didn't take it home at lunch, just spent my lunch hour at the welding bench at work... Although it would be SWEET to be able to take that welder home once in a while, then I could pratice all night!

*Snip*.... a common technique is to pre-heat aluminum as well as sometimes using your filler to start the puddle. If you are fillet welding aluminum, you will need to make sure you have a nice ball on your electrode as well as have a good sized protrusion, usually 20% more than aperature of the lens.

I tried using the filler to start the flow but wound up chasing the bead away and then had a glob higher up on the electrode when I took the tungsten out of the ferrel.
So which piece is the "Lens" you guys are refering to? motofiaccone spoke of it as well. Is it the Ceramic "tube" that screws over the electrode that focuses the arcon onto the weld? If that is what it is, it just dawned on me with your term apature, the one I used was red tinted, should it have been green like the tungsten?
Also the tungsten was small, but larger than the smallest collet and ferrel I found, I had two choices of collets for the holder but only one diameter of tungsten electrode to choose from. Would buying a pack of smaller tungstens to fit the smaller collet help?

 

[beater]

there are two types of gas shields on a tig torch, a cup and a lens. cups are just that, a ceramic cup that surrounds the electrode and "corrals" the gas around the weld area. A gas lens is a cup that is integral with the collet, and has a diffuser screen to diffuse and flow correct the gas flow around the weld area.

By your descriptions in your last post, I can come up with a couple of thougts.

a - your base material was not clean

b - your polarity was possibly reversed

c - your tungsten wasn't balled and of sufficient thickness for the material

d - your amperage was not high enough

e - about 10 other things that I don't have the time to type out.

Tig on aluminum is precision stuff. In fact, I find that Ti is easier than aluminum. I am not a miller endorser, being a lincoln man, but... the miller welding forum is a WEALTH of knowledge and help.

for short burst jobs on aluminum on a home user mig machine, you can buy drive roll kits and liners for your small 210 mig welder. A simple trick is to pre-heat your wire to 170-190 degrees before loading it, to help with the flow through the rollers and to prevent balling up in a rats nest or breaking at the drive rolls.