Carbon buildup with my 210 on AL

[SoCalTA]

Hello guys ....

Been a long while since I have been on. I have managed to get a good handle welding with my spoolgun on 1/8 AL. I have a problem however that I can't seem to figure out. I seem to get a lot of splatter and black carbon like build up on my welds. If the splattering isn't enough to make a mess the carbon like build up is a bummer. I can't complain since my welds look better than before but if you could direct me on what I am doing wrong and how to fix it I would appreciate it. For the record I am running .030 wire on an .035 tip, 100% argon and welding on a fantastic MM210 with the spoolgun. Oh I am using my air grinder to sand down the surface before I weld and clean it up with either Acetone or brake cleaner.

Thanks .....

[df5152]

what flow rate do u have your regulator set too?

[SoCalTA]

I should have mentioned that as well. Thanks for asking. I tried anywhere between 20-21 down to about 15-17. Would the amount of gas left in the tank be a cause?

[df5152]

if the tank is very low it maybe cause a problem usually the black is a shielding gas problem or lack of. is it all the time or at the end of the weld?

[SoCalTA]

all the time. Anything from a simple tack to a long bead

[lramberson]

I am gonna jump in on this, I just completed a large project with aluminiun tube, The spoolgun produces this as a normal process in this operation. Kinda like slag with rod welding, mine kleens of with a simple wipe of a rag after cooling & for that factory fresh look I hit it with a scotchbrite disk..
I was informed it is normal,(I hope I was not mislead) the welds have good penatration, nice formation, & strength is excellent...
And lastly I am pulling the gun with a 45* angle & 15* angle back.

[timw]

You could be getting contamination from the sanding disc. With Alum you should clean with a stainless steel wire brush. Even steel brushes will contaminate Alum. Also I like to push on Alum, it directs the gas and heat out in front of the puddle. With Alum that is not real clean I will go slower and let the puddle burn off the contamination in front of the weld. This works on steel too. I've welded a lot of Alum semi trailer refridgerated floors and they get animal fat on them and are hard to weld. They also out-gas from the insluation and ruin the weld. If you go slow it burns off but you still clean a lot.

[sparx]

Couple of things.....

Iram- The proper technique for aluminum mig is to use a lead angle and push technique. The best way to remember the direction of travel is this- "If there is slag, you drag"

SoCal- If the black "carbon like buildup" looks like soot, then that is basically what it is. The proper technical term for this deposit is "smut". You will notice this a lot more when you mig with the 5XXX series filler rod/wire than other alloys or Tig welding. It is caused by metal vapor being produced at arc temperatures, and being condensed on the base metal. Since the arc temperature is higher than the boiling point of aluminum, some of the filler metal vaporizes in the arc plasma, and then condensates on the "cooler" base metal (even in the HAZ). The smut is basically finely divided metal oxides, and although not harmful to the weldment, they definitely don't add to the visual appeal of the weld. This SMUT can be removed by wiping soon after welding or if left on too long, will need to be wire brushed.

Hope this helps.

[Scott T]

Turn Up your gas flow, I run 40-60cfh. Wire brush cleaning for wire feeding is good enough, you are pretty much just wasting time with the acetone unless you are removing something other that oxides. Scott

[SoCalTA]

thanks guys ..

I will try out some of the suggestions today.

[hankj]

SoCalITA,

Nice to see you back. Missed ya. I've got a 210 w/3035 now, too, and I get the same "smut" as you do, but the welds are good. I just buff it off, and grin while I pound 'em flat in the vise with the BFH and the welds don't crack!

Hank

[SoCalTA]

Hello Hank,

Nice to be back and great to hear from you. Glad to hear you got yourself a MM210 w/3035. I love mine and am thankful for your help when I was trying to figure out what I should do.

Two things I want to toss back out there. Is the splattering affect part of the smut creation process and do I need to change my pressure settings? I usually work in the 15-20 range with al. I work right now on 1/8 AL and Steel.

Thanks also to the others that have answered.

Jorge

[ASKANDY]

One more thing, Are you using 4043 filler??? the 5356 filler will give you a more sooty weld. Also, what is the base metal? Some base metals like some of the 5000 series will do this.

Andy

[jeffscarstrucks]

I would use acetone and not brake clean. It is my understanding that brake clean leaves a carbon based residue that can effect weld conditions. I would like to know if this is a standard rule or one of those "wives tales" kind of things. I read it in a couple of credible sources but that doesn't always matter. JEFF

[paulrbrown]

sparx
very good description of 'smut', the oxides, Aluminum and Magnesium, more so on 5000 series as Andy mentioned are so dense they will not let light penetrate or reflect, hence the black look instead of the expected white of regular oxide. Hope this helps, Paul