sheild gas for weldin aluminum?

[boardmanr]

ok...i've was trained to use 100% argon or 75 argon and 25 helium to tig weld and mig weld aluminum but i seen on another site won't say who but they say to use 75 helium and 25 argon...which helium is a hotter burning gas.. and is light but my ? are they right is that the right mixture to mig and tig weld aluminum with?

[welder_one]

you can, but DANG that is going to be expensive. i also dont see the problem with using 100% argon. its what i use daily on aluminum usually more than 3/8 thick. sometimes 2 inch thick, and dont have problems with penetration.

[HMW]

I use straight Argon for both MIG and TIG. Thickest I have welded aluminum is 1/2" and argon works great on all that I've used it for.

[FusionKing]

ok...i've was trained to use 100% argon or 75 argon and 25 helium to tig weld and mig weld aluminum but i seen on another site won't say who but they say to use 75 helium and 25 argon...which helium is a hotter burning gas.. and is light but my ? are they right is that the right mixture to mig and tig weld aluminum with?

The need for different gas changes with what you are welding on with a particular machine. If you have enuff amps to weld a piece of 1/2" with straight argon well good for you, but if you can't get enuff heat then helium allows you to do this with a less capable machine. For example a 200 Dynasty is a fine tig welder but has a limit to what it will do and by using helium it can weld thicker metal than it would with straight argon and it will let you turn back the amps on less thick material to a setting where the duty cycle is higher.
It can be confusing at first but after awhile it isn't all that big of a deal...just keep reading and asking questions.