Making the transition to welding aluminum

[aroy]

I am having some trouble moving to aluminum.

In searching the web for tips I only find a few.

I have some questions.

1. I found a reference to 100% argon being required to make good Al welds.
I also found this in forum. (I'm using C25)
2. I find a reference that states you must push.

Are these statements true in general?

I haven't found any examples of 'bad' weld symptoms with cures.
like 'balling up' of weld material - what we used to call 'bird ****' in stick welding, for example.

This would be really handy, does anyone know where they could be found?

Roy.

[Arbo]

Both statements are in fact true. You do need argon, and you must push, to keep the argon ahead of the puddle.

[Hobart Expert Kevin]

Aroy,
The article I have attached the link to below is very informative
on aluminum welding and may answer many of your questions.
Hope it helps...

http://www.millerwelds.com/education...articles10.php]www.millerwelds.com/education/tech_articles/articles10.php[/URL]

Kevin

[email protected]

[aroy]

Thanks very much!

The article at millerwelds is excellent.

I had another question which was answered in the article!

I also broke down and bought a book put out by ESAB which is very informative.

Roy.

[Hobart Expert Kevin]

Roy,
Glad I could help now you just have to put all that information to work. I can hear the wheels turning already on all of those cool projects you are planning... Time to have some fun....

Kevin
[email protected]

[aroy]

Hi Guys,
OK, I got a small tank of argon.
I moved the job into the shop so wind doesn't blow the argon away.

I am welding brackets onto some aluminum racing seats.
The seat material is 5052. The brackets are 6061.
I'm using .035 ER5356 wire.
I'm cleaning the surface with a wire brush.

I have an 'inexpensive' welder which has worked great for steel.
I find it extremely difficult (nearly impossible) to get the wire feed rate and current balanced right, but I'm sorta-kinda there. I don't seem to be able to get into the 'spray' mode consistantly, but I have made a couple of marginally acceptable welds.

The big question in my mind is - Why do I see a grayish-black deposit, like carbon, even though the gas is pure argon? Doesn't this indicate I don't have a good gas pocket? Even so, where can the organics be coming from? The material is new and clean.

The Miller article says increase the voltage and get into spray mode, if I do I can't get the feed speed and current correct, apparently. The wire melts back most commonly and destroys the tip, even though I'm staying around 3/4" back.
I may not be holding the correct angle.

Do you have any suggestions other than 'LOTS' more practice?

Roy.

[Franz]

Just one cautionary note here, in case you don't already know, ARGON is very toxic. Since you moved to an indoor location, make certain you are venting the argon out of your welding area for your safety.

[Planet X]

Originally posted by Franz
Just one cautionary note here, in case you don't already know, ARGON is very toxic. Since you moved to an indoor location, make certain you are venting the argon out of your welding area for your safety.

I thought it was just heavier than air- granted suffocating would suck

[DaveH]

Argon is inert. The worst it can do is displace the air and deprive you of it. I couldn't really see that happening in a garage.

[Seldom]

Been there, done that!
I used a Millermatic 35 (white-faced for the old fellas reading this) many years ago to weld very thin tubing (pontoon frames and such) and did a satisfactory job but I spent a lot of time trouble-shooting and finding its limitations.

That grayish black deposit stuff you mentioned could be coming from the your wire being contaminated. If you haven’t replaced your original flex cable liner with Teflon one, your aluminum wire is probably picking up all kinds of copper sheathing left from you using CS wire. Even blowing the liner out with compressed air won’t clean it either.

Using .035” wire even in the stiffer 5000 series with a Teflon liner doesn’t want to “push” well at all and will bind in the liner as it takes a “set” off the roll(s). A .045” wire would be more appropriate with a short whip and no “push-pull” type gun. I would suggest because of its stiffness but then you have to think about being under-gunned for machine.

I would also suggest you use the next larger size tip regardless of wire size you choose to use and a short, straight whip. Aluminum melts at about half the temperature of steel so if the tip overheats it will soften the aluminum wire as well as pinch it. Couple that with it not wanting to push and you’ve got trouble at the tip!

Also, you may be under-gunned in the power department with a duty cycle that won’t allow any time in the spray range to weld without a shutdown happening. With whatever machine you’re using, I’d almost bet you’ve seen a tip or two actually melt the end off by now!

I don’t have a qualified WPS for .035” wire but here’s a “generality” for welding flat fillet welds on 1/8” material with .040 wire - 150amps/23v/190imp/30cfh argon.

There are reasons why industries use either "pull" or "push-pull" guns, that are water-colled, larger diameter filler wires, high power output machines, and argon/helium mixes for welding aluminum! LOL

Good luck.

[aroy]

Hey - thanks a lot.
The tips about wire and tip size should help.
Not only have I melted tips full of aluminum but actually eroded the copper on a couple.

I haven't found a high current setting which works for me. 150 amps is the max capability for the welder but it's a 220 input and a pretty good capacity connection. I 'might' be running at 80-100 amps. Hard to know.

They have a welding bench at the local Praxair store. I may go down there monday and try out a Miller welder just so I get the feel of what it's like with the right equipment.

The 'smokey deposit appears very similar, if not identical, to what you see when you are trying to weld Al with C25.
Is it possible they (Praxair) sold me argon contaminated with CO2? The quantity of deposit appears too much to 'just' be from the liner but I find it hard to believe they would screw up like that.

It's usually a good idea for a beginner to blame his problems on himself but occasionally ...

I've made some progress in improving the quality of my welds. I was having a hard time getting a good pool going. Still am, actually.

I'm going to try some more practice pieces today - from everything I've read I think I may be keeping the tip too close to the workpiece.

I think I'll be able to do a reasonable bead about the time I'm finished!

[Seldom]

It certainly gets your attentioin when you blow a tip doesn't it! LOL

There’s always the possibility of getting a cylinder of argon contaminated with CO2 but as time goes on, the chances get slimmer and slimmer. The reason for this is the fact more folks are buying 75/25 rather then mixing their own. Years ago when many shops were still mixing their own, contamination were not infrequent. You’d run through several cylinders of argon to one CO2 and without backflow prevention, the argon cylinders became contaminated. This contamination easily/quickly showed up when tiging SS or nickel-based alloys.

Good Luck

[aroy]

Well, I ran some practice beads.

A couple weren't too bad.

Ate some breakfast, went back out and tried to weld a bracket.

Absolutely could not get a pool going! Beaded up and no penetration. Increased the power - still not good. At least I haven't burned up a tip yet today!

I am not getting the same amount of 'smoke deposit' that I was so maybe the surface or liner was/is contaminated.

The inconsistancy is driving me nuts!.

Roy.

[Roger]

When welding aluminum you should use exstended nozzle so contact tip is recessed. That way you can use longer stickout and still have good shielding. Aluminum is much better electrical conductor than steel wire so not significant increase risistance with longer stickout. Longer stickout also helps with some of the heated related problems.

Some companies make special contact tips for aluminum wire with over sized bores. Following is from Kemppi Publication "Pronews" artical using metric wire diameters. www.kemppi.com

Wire Dia 1,0 1,2 1,6
Tip hole. 1,6 1,8 2,3

Kemppi is also big on giving MIG welder synergic controls on MIG gun. Their new push pull gun has variable speed gun trigger as used on variable speed electric drills only you program upper and lower speed limits.

[Seldom]

Well Aroy, Lets try something that hopefully will point to or eliminate your power supply as the primary source of your puzzle. You haven’t stated your base material thickness but regardless, try some preheat. I’m not talking about a couple hundred degrees; I’m talking about 500-700 degrees! Get a splinter off a piece of pine to use as a temple stick. Heat your weldment enough so that when you drag the pine splinter on the surface near the weld joint it leaves a dark smear (that’s around 600-700 degrees). When you see that indication, try to weld. Make sure your joint is freshly cleaned of oxide with a SS brush or a grinding wheel specifically for aluminum and you’ve purged the air from your whip just before starting the arc.