is it all in the settings or prep or technique ? or do i just need alot of practice.. i just made a seat bracket for my dads 36 chevy with aluminum box tubing, i was welding it with tig and started out nice but after the aluminum got hot i couldnt get the welder to calm down + it was making crappy/porus welds. the metal wasnt the cleanest, the tip wasnt fresh, it was my second time welding aluminum with a tig. first time was all practice. i had to finish it with my mig now its strong as hell, but it doesnt look as good as it could have with the tig. any tips?

 

What machine
What tungsten
what balance
what gas
what rod
what tube material


Lots of questions, Aluminum is very hard to master, especially if any one of those things is off. Cleanliness is key, and probably number one on the the preweld check list

 

not sure on any of those, its miller somthing.. gas = pure argon and idk the rest.ill hafta check. but what should i clean the aluminum with i used sandpaper it seemed to help, but this was brand new aluminum so i didnt think it would be too bad. it did look like it had some kind of coating though... i used to have tha acid w/e for cleaning the aluminum but i think im out. i already finished the seat bracket i just wanted some tips for future reference.

 

Make sure:
1. Clean the piece. Clean it again. When you think its perfectly clean, wipe it down with acetone. If you brush it, ONLY use a stainless steel wire brush. Wipe with acetone again.
2. Make sure you're using a PURE tungsten, no alloying metals (no thorium, no cerium, etc.) Grind it to a rounded edge (no point). It will ball up when you start welding, this is what you want.
3. Set the machine to AC (finer options depending on machine)
4. If the work piece is large, pre-heat with a clean burning torch, and do not heat directly over the joint (keep carbon/soot out of the joint).

Aluminum will oxidize in mere minutes, so if you leave it sit any duration of time clean it again. Make sure your tungsten is not contaminated. If it is, snap/grind it again and start over. Do not try to weld with a contaminated tip, or you'll just blow crap back into the weld and you'll have to grind out the weld and start over.

Oh, after you wipe the joint down with acetone, let it evaporate so you don't start it on fire with the welder

Keep in mind, aluminum skins over and doesn't flow like steel will. Its harder to see the weld with aluminum, you kinda have to lead it with the torch and fillter rod.

 

How thick is the material your are working with? And how many amps are you working with? I would assume as well that you dont have a pedal or wheel adjustment on the torch? Reason I ask, if you have the torch burning too hot, it will be ok for the first parts of the weld, and then your work will start to really break down. It will either melt into goo, or impload. having the work clean is very important, but just as important to know your heat range, or atleast be very close. For learning and doing what you are doing any common aluminum rod, pure tungsten, and 100% argon should atleast give a workable weld. If you blow it up, its probably too much sustained heat.

 

i do have a foot pedal. welder is a miller 180 sd i just looked earlier today.. dont know what kind of tungston or w/e it has no markings. it was dirty though and the metal wasnt as clean as it should of been so i'll start with that next project. 100% argon gas, aluminum 4043 rod. and im not sure exactly how thick the aluminum was, maybe 1/8 inch rectangular tubing. its done now i just wanted to know for faster learning next time. i finished it with mig, i just would of rather had a nicer looking tig job on it... i might just polish the mig welds there ok just smoked over. i did have the heat right when it first started probly even alil too cold as it took really long to get a puddle started, but twards the end i let almost all the way up on the pedal and it was still too hott for it, it kept melting up the wall. welding inside corners where i couldnt see to well. probly not the best type of welds to start out with. i mostly want to learn tig to complete my welding knowledge too. its the only type i havent mastered yet. got steel down with tig, the aluminums always alil more tricky though. thanks for the help sofar.

 

oh forgot anyone know if aluminum is usually coated with something being brand new ? the stuff i got seemed to be. i sanded it and it went to a lighter shade.

 

Good advice and I would ad that if the piece is very small clamp it to a larger piece, aluminum has poor hot strength and if your welding and suddenly everything goes south you have overheated it or it may be to dirty, sometimes you will notice what looks like a "skin" over the weld pool than it needs to be cleaned better.I use a chemical cleaner for aluminum, dont recall off hand what it called but it works well with a little stainless wire brush for really dirty pieces.

 

and dont ever use sandpaper to clean up the metal, it just pushes the dirt into the metal. also like someone else said only use a STAINLESS STEEL wire brush. and if the metal is real dirty only moove the brush in one direction to keep from throwing dirt back into the area you just cleaned.

 

I just learned how to tig weld aluminum and i'm no pro but i read a lot and practiced a lot. it has to be very clean, also if you touch the aluminum just once with the tungsten you will have to regrind it. when you grind the tungsten grind so that the scratches go from the back to the "point" which is parallel to the tungsten itself not in circles around the tungsten. Right way is like sharpening a pencil with a knive (cut from back to pont straight out) not llike when you sharpen a pencil in a pencil sharpener where you turn it. Dont make a point though it should be almost a point but with a flat end. make sure you have enough argon flowing too. better to waste a little more argon with higher flow and not mess up the metal and the weld. once the aluminum is contaminated even if you clean up it's a pain to get a clean weld in that area again. and dont weld continuous or you will overheat. go on and off with the pedal to keep it from over heating and stop once in a while for it to cool, the machine has to cool too. you can run water over it to cool it. a good heat sink material for the base is good too. i have some scrap thick chunks of granite that are over an inch thick and polished flat on one side which is scrap from a place that does counter tops for free. i havent used it yet but it should be great. used bricks or some type of rock. make sure you get good flow to the area before it jumps so that is starts clean. and get used to grinding that tungsten cuz i had to do it a lot but eventually you'll do it less. good luck. oh and to help with welding on and off with the pedal get a autodarkening welding mask. i know harbor freight has bad quality but i got a great autodarkening welding helmet for $50 and it's adjustable darkness up to 13 and solar powered (from welding light). cant get for less than $100 anywhere else. here's a link: http://www.harborfreight.com/cpi/cta...emnumber=91212
it just went up in price it's now $70 and it used to be $50 well then get the blue flame one on the right which is $60 it used to be $60 (same helmet different color). good luck.

 

thanks for all the tips. im sure it was dirty and the tungston wasnt grinded, still hafto get a dedicated wheel for that.i hafto also get a new s/s brush i have about 3 but there all contaminated/falling apart. my dad used to have the liquid aluminum cleaner it was a type of acid,seemed to clean it great, but i got acetone so that would probly work too.. i already have a great welding helmet(280$) miller autodarken came with helmet bag, american flag painted on it, and a few extra things. well worth it. im singin up for a tig/mig class soon, even though i already know how to mig well, im sure they can teach me a few new things.