Aluminum Welding?

[GaryM]

Ok I need to know some things about tig and mig welding aluminum.
Satarday i am going to meet with the production manager for a Aluminum boat outfit and well I have tig welded but never on aluminum.

The aluminum is 5086 so you know what will be welded. as you could see on a boat there will be out of position welding so any info would help very much.

They use all miller tig units so you can give me some tricks you just my help me get out of welding Galvanized tubing everyday. Darn nasty sutff.

Thanks
Gary

[timw]

I can tell you about mig and Alum. Alum runs pretty easy but the metal has to be clean. Cleaned with solvent, acetone is best, and wire brushed with stainless brush. (steel brush can leave contamination behind) When migging Alum the machine settings are more sensative, you might have to ajust as you go depending on the material and shape. ALSO I HAVEN"T SEEN IT MENTIONED IN THE POSTS I"VE SEEN BUT YOU WILL BURN MUCH FASTER WITH ALUM, BECAUSE OF THE REFLECTION, be sure to cover up. I once welded for about 4 hours in a squating position. My pants rode up and I got burned above my socks. Both legs with 2" strips were purple and sore for about 3 weeks.

[HAWK]

Gary,

Aluminum TIG:

It is hard to know what to tell you: When you get a good shiny puddle with aluminum it is time to add filler and move the torch forward, add filler and move foward again. The torch angles are basically the same as other materials. It is a common mistake to get the torch too far off from the vertical-20-30 degrees off the vertical with the back cap leaning toward the back or beginning of the weld is a good rule of thumb.

For amperage figure your material thickness and convert to a decimal amount: 1/8"=.125 therefore 125 amps is a ball park range for your amperage adjustment. If the machines have adjustable arc frequency and you are using pure argon, then around 100 is a good place to start. The higher the frequency the narrower and more focused the arc. If you have the option to adjust balance, 75% electrode negative is a good place to start. If you get a good whitish color line all the way around your bead, the balance is set correctly. This indicates good arc cleaning action.

Positions are as with any other method: It takes less amperage for a horizontal than a flat or in position fillet. Verticals usually take even less amperage. With TIG the trick is to run verticals uphill and treat each individual bead as a shelf to stack the next on one.

As timw mentioned cleaning is a biggie! I also use a Scotch-Brite pad to clean my filler rod, then wipe down with acetone.

There are so many variables and particulars. If your puddle starts running away with you, back off on the foot pedal a bit to cool the puddle and get it under control.

The best thing I can say is watch the puddle. When it forms move on. Don't wait for the burn through and it is too late. Tig is not as critcal to speed up once the material starts heating up like mig can be. Once your material heats up after the first few inches with wire welding you must really increase you speed to avoid burn through. Tig is a bit more tolerant on that-especially on larger surface areas like a boat hull. You will still have to increase travel or maybe back off the pedal, but don't have to react quite as quickly as with mig.

When mig welding aluminum, push the mig torch forward with about a 15-20 degree angle off the vertical. Also get a good stick out around 3/4" -1". This should cause the arc to go into a spray mode and freeze as it contacts the base material. It make out of position much easier.

Best of luck!!!

[GaryM]

Thanks for the info I will try my best and take my time!

I would rather have a bad looking weld then a big hole to fill. Should do fine my mild and stainless steel welding with tig have come a very long ways quick. I guess the practice is helping.

Gary