first post in the fab thread

anyway, I've been tig'n for a long time now, mainly with mild steel and stainless (and some exotic metals) but I have yet to try my hand out on aluminum. I recently bought my own tig machine too, and figured I may as well start up a little shop out of my garage, so if I'll be doing any work on car parts I'll need to know aluminum. Are there any rules of thumb to follow with this process? typically the same heat as with steel (based on material thickness)? I know the theory behind aluminum, AC this, AC balance that, but just want to know if there's something I should know before trying it out. the only thing I can think of with me having problems is aluminum's low melting point, and when I go to dab, the rod will just melt in front of the torch and I'll get a crapload of filler metal in each puddle

 

Clean Clean Clean. That is the biggest difference when welding aluminum. Steel and stainless both tolerate some carbon or other contamination. Aluminum must be very clean, including the filler rods.

Aluminum seems more sensitive to the size of the filler rod too. You need the right size filler for what you're working on. Too small and it melts before you get it to the pool. Too thick and it cools the pool too much and you get cold spots in the weld (which may not be visable from the outside but will weaken the weld). Aluminum takes more power than steel, but you also tend to travel slower, so the same settings are usually pretty close.

- and clean some more.

-Chris

 

I'm bumping this one. Can anyone expand on this thread?

 

I agree with EMod Civic.

The only things I can add are to brush/clean the aluminum with a stainless steel wire brush and if possible use A/C when welding so that the DC (+) wave can help clean the oxides off of the aluminum even more.

 

Anything else?

 

Pure tungsten

Gas lense always helps.

I weld with 2% thoriated because i don't have any pure lol, works fine, but they recommend pure or 1% (white or green)

 

aluminum will pick up dirt from anywhere when welding it so not only should the metal be clean but clean your work area as well before i ever weld aluminum i wash my hands first and dont use gloves just because when using your gloves they will contaminate the part of the filler rod you are handling. So if you do use them make sure they are clean also the biggest problem with using pure tungsten is that if it makes contact with the bead when arcing it will contaminate up to an inch of the tungsten. I recommend using a 1.5% or 2% lanthinated tungsten (gold band or blue band) also when cleaning the metal dont use something that is very abrasive i have found that the smoother the surface is the cleaner it will weld.

 

you can also hit up your local welding supply for a gold gas mix. it usually consists of 70% argon,12% helium,18% special mix.

 

i agree with all that has been said so far. the only other things that i could add is use meriatic acid to clean filler rod and base metal.connect ground directly to the base metal, and also, i recomend you using pure tungston (green).also set your pre and post purge flow to cool the tungston and to keep the tungston clean because it will pick up any air born debriee and will contaminate it.let me know if you need anymore help. i am certified in GTAW aluminum,Stainless, copper nickle,chromoly,low and high carbon steel, ect.pretty much everything but titanium and nickle-cabnium.peace

 

i think weld clean would be better for cleaning rod (and surface)! I dont disagree with the acid coment but i dont recomend it. you can pick up weld clean from any welding supply store.

 

I use a fresh scotch brite roloc wheel and acetone and it works pretty good.

 

I use Zirconiated tungsten (WHITE), has a higher current capacity then pure, and has less ARC wonder. Once you have sanded, grinder, or brushed the material, use some acetone to clean it off. Just be quick with the pedal, once you get the puddle going, it gets real hot and you need to back off. With ALUM i usually match the filler to the tungsten size. Enjoy

 

oh yea mek works good too!