Welding Tips and Tricks

Trying to weld 5mm aluminum and am doing something wrong:

Lincoln Electric Tig200 Square Wave machine
AC 150 Amps
Pulse OFF
balance 60%
Freq 100
Gas: Argon 18CFH
3/32" 1.5% Lanthanated Tungsten slightly rounded tip (with diamond grinding wheel.)
3/32" 4043 filler rod (which never actually got added..)
Preheated to 150°brushed with dedicated AL wire brush and wiped with Acetone.

Thanks in advance!

I cannot get a puddle to form. The material simply gets too hot without puddling.

General rule of thumb, if the puddle doesn't start in 3 seconds or less, need more amps.

In general, Aluminum likes amps, be bold, hammer down. Once puddle starts, back off pedal as needed.

However, your pieces are small and you may have to back off the amps almost as soon as you get some filler in the puddle.

Try starting the puddle with all 200 amps. Don't "sneak up" on the amps like is possible with steel.

Being gentle, and/or using too low of amps, the aluminum edges melt away from each other.

try turning up the amps and get a tack on each end first.
craig

I found it useful when I learned to weld aluminum to start in the middle of the flat piece and run a decent bead with filler to get a feel for starting the puddle and maintaining proper heat. I still do that exercise because I'm a home hobbyist who doesn't weld every day. Then I moved closer to the edge to see the effects of having less aluminum mass to conduct the heat away. Then I gradually rolled over on the edge of the aluminum, and finally tried different joints. The hard part with aluminum is that it takes a very large initial pulse of heat to get a puddle going, then you have to back off really quickly on the heat, or else push a lot of rod into the puddle to keep the piece from melting and burning through. For aluminum I don't try to guess how much current I'll need, I dial up to 200A and use as much pedal as necessary to quickly form a puddle.

Thank you for these great tips! I never would have thought that I needed even more heat to start the puddle but that was key to my problem!
Now I just have to learn how much to back off before I melt the entire piece!

johnny340 wrote:Thank you for these great tips! I never would have thought that I needed even more heat to start the puddle but that was key to my problem!
Now I just have to learn how much to back off before I melt the entire piece!

Yeah that does get tougher when your part is that small.

You'll find it get easier when the parts have more mass. Everything is a little more predictable.

MarkL wrote:I found it useful when I learned to weld aluminum to start in the middle of the flat piece and run a decent bead with filler to get a feel for starting the puddle and maintaining proper heat. I still do that exercise because I'm a home hobbyist who doesn't weld every day. Then I moved closer to the edge to see the effects of having less aluminum mass to conduct the heat away. Then I gradually rolled over on the edge of the aluminum, and finally tried different joints. The hard part with aluminum is that it takes a very large initial pulse of heat to get a puddle going, then you have to back off really quickly on the heat, or else push a lot of rod into the puddle to keep the piece from melting and burning through. For aluminum I don't try to guess how much current I'll need, I dial up to 200A and use as much pedal as necessary to quickly form a puddle.

I have a thing about a weld filling the joint at both ends. As the aluminum workpiece gets hot, I find it very difficult to keep the very end full. Run off tabs are a solution, adding helium is an expensive cure, but a thrill. Or, I can begin at one end, weld to center, then begin anew at the other end. Beginning an aluminum joint must be approached boldly, with courage. Gobs of heat will not cause problems beginning. Zap talks of leaving his 350 amp welder on KILL, and using full pedal to start. Of course, southern Massachusetts dims when he does.
Willie

I had a bad habit of easing in with the pedal trying not to blow any holes, but ended up making it worse. Got the confidence to drop the hammer and was amazed at the results.

Just a further follow up:
I now have good success using 1/16" tungsten on pieces this size, clamped tightly to start, using up to 135 Amps rapidly to start and then backing way off as the puddle forms and the part heats up. Breakthrough for me!

johnny340 wrote:Just a further follow up:
I now have good success using 1/16" tungsten on pieces this size, clamped tightly to start, using up to 135 Amps rapidly to start and then backing way off as the puddle forms and the part heats up. Breakthrough for me!

Try even more at start. Practice toward welding faster. As skill improves, results improve. Aluminum wants welds outrunning the heat dissipation that characterizes aluminum welding.

Steel, or stainless steel won't conduct heat as fast. Still they distort less, and have a smaller Heat Affected Zone (HAZ) if welded with more heat, faster. Aluminum is very sensitive to this phenomenon. It is necessary to start slow, gain skill, then speed up. Therefore, we need a good supply of scrap aluminum for practice.

We really need an aluminum sticky.

Just for aluminum ? - how about a post " I just bought a shite welder off Ebay but it don't weld like Jody " !

Oscar wrote:We really need an aluminum sticky.

If your aluminum is sticky, increase amperage

Those pieces are way too small to start learning to weld aluminum, I know I was just there.

for the Lincoln Square Wave Tig 200 I have found that you must use a gray banded electrode. Green, red and blue do not work. I don't know why but that is what I have discovered.

Bill

discap wrote:for the Lincoln Square Wave Tig 200 I have found that you must use a gray banded electrode. Green, red and blue do not work. I don't know why but that is what I have discovered.

Bill

2% Laninated (blue) works fine on my 200.

When i did my fuel tank 1/8 inch diamond plate I used 3/32 purple tungsten at about 160 amps.

Looks like similar issues to what I was having - http://forum.weldingtipsandtricks.com/v ... 2&start=10