MIG Welding Aluminum

[carlmcmas]

Hello All!

I am trying to get the correct settings on this dinosaur to weld aluminum. (063, .080, .125) I am using a Miller Spoolmatic I, the machine runs off of Argon. Looking at some of these photos I just dont know where to begin. Attached are some pictures of the welder and some terrible welds. Any help would be appreciated. Have a good day.

 

[shenion]

You are using pure argon?

Is that 5336 wire?

The voltage looks a bit low. I would expect at least 18-20V.

 

[simon718]

welcome mate

did you clean the sheet first with a (new) stainless wire brush?

 

[madkayaker]

that unit looks like DC output I thought you needed AC for Aluminium (not sure why though)

 

[simon718]

Need ac to break through the oxide layer on the surface of aluminium

Edit: just realised its mig, 99% of migs are dc so thats not the problem

 

[madkayaker]

thanks for that. Looks DC through as it labeled POS NEG

 

[shenion]

AC is used on TIG to clean the surface on the positive cycle.

This is MIG and that is a MIG power supply.

 

[madkayaker]

Just realised that Hadn't read the title properly. Will it matter whether its straight polarity or reversed? Ignore the AC bit

 

[malcolm]

Polarity should be straight. Looks like a problem with the shielding gas to me. The weld should end up shiny and that one is laying aluminium oxide. DC is fine for MIG (though welding with TIG on AC is much easier).

Pure Argon for shielding gas. Mixes or CO2 won't work. If it's a disposable bottle probably the flow rate is too low. Otherwise torch might be too far from the work.

Alu will need to be clean when you weld it (see http://www.mig-welding.co.uk/aluminium-welding.htm), but you should get nicer beads than that even on dirty aluminium.

 

[carlmcmas]

Thanks for all of the advice. I did not clean the aluminum first. The gentleman who fixed our gun was able to lay a nice bead. Of course I didn't pay attention to any of the settings and changed them

Is it the forum consensus to try to set it on between 18-20 volts?

 

[dannyweld]

are you sure that sheet is aluminium!!

 

[Sparkey]

are you sure that sheet is aluminium!!

Now you mention it....it looks a bit like galv....or not?????

 

[Archie]

Now you mention it....it looks a bit like galv....or not?????

That's what I thought it was when I first looked at it.... It's got that flaky look.

 

[dannyweld]

i'd nearly (and thats nearly) put money on it thats galv just from the look of the welding.

 

[malcolm]

Well spotted. Though with flash photography and a little corrosion on the aluminium it could be either from the photos. Hopefully that's the trouble as it would be a nice easy fix.

Certainly there's something up apart from the volts and wire speed in there. 20volts ish would work OK for thin stuff.

 

[Tino]

You don't say what size wire you are using, but for that thickness 1mm wire and about 18-20volts would be OK for me.

 

[carlmcmas]

The wire is .035. The metal is aluminum. If it isn't I need to shoot my aluminum supplier

 

[shenion]

What gas are you using?

What type of wire?

 

[carlmcmas]

Rule #1. Before asking a question, make sure the gass is turned on

Needless to say once I turned on the gas, it helped

Thanks for all of your help!

 

[shenion]

Yeah, did that once. Worked more like a plasma cutter than a welder