[Follow da blue light]

Good afternoon gentlemen.

I have just taken a new job as production supervisor at a metal shop, I start Monday week.
While being shown around the shop after acquiring the new job I noticed the ali mig welding section had black soot on the welds.

I have done an extensive amount of ali mig welds myself in the past and never once got black soot.
When I weld ali I always clean with acetone to remove any contaminants then brush with a SS wire brush, gas is Argon.

What could be causing the black soot?
I have no idea of the gas or technique used at the new job site as it was quick and fleeting tour around the shop.

Also, how do you remove the black soot once it is there?

[Oddjob83]

I find when all the planets align and I've had my morning coffee, I can weld aluminum and not get soot. For me there are two types of soot, the black stuff around the outside of a weld can be wiped off with a cloth and little to no effort. the soot you get from pulling the gun is more grey and is on the weld and around it, and i find that a wire brush works fine on that.

[Otto Nobedder]

I have a few ideas.

First, though, since this appears to be a MIG question, I'll move it to the MIG subforum, where it'll get more traffic from the MIG guys.

Steve S

[Otto Nobedder]

Black soot, eh?

I'd look first at the argon supplier. Impurities, particularly moisture, can cause that soot. You can install dessicants in the argon lines between the flowmeters and the machines on the cheap. Maybe just one station, to see the result. If the color changes, they're absorbing moisture, and of course if the soot goes away...

Another possibility is in the wire. Mainly how it's stored, and whether it can pick up anything from the air. Are they using cleaning pads? If not, they should. Are they using "Wire-Kleen"? If so, they shouldn't.

Also, perhaps they began as short-circuit guys, and tend to run too much wire/too little voltage for the spray transfer?

Just some thoughts...

Steve S

[Oddjob83]

Hadn't thought about moisture issues myself. I do notice if I am running a straight bead, if i change my gun angle for some reason, ie. cough, have an itch, or the cord gets caught on something I will get black soot when I have a less than optimal gun angle and I'm not tuned in right even the temp of the metal its self.

[Braehill]

I've read that the black soot is actually Magnesium oxide and if they are using 5356 and or are welding 6061 they both have higher Mag. content. If that's the case you might need an adjustment in gun angle or even try upping the flow rate on the shield gas, which will add to the cost. Not that a post weld cleaning doesn't add cost.

But as the new Production Supervisor you'll need to look into these cost comparisons and write a report and send out a memo and if need be, send out a companywide mandate. You need to start acting supervisory, you have until Monday to loose all your common sense man. BTW Congrats on the new job.

But all the afore mentioned issues can and will cause it also.

Len

[weldin mike 27]

Hey,

Have a look at this, sort of like a gas lense for mig. supposedly great for alum welds.

http://www.bernardwelds.com/centerfire- ... j7NBj9aaSo

Mick

[noddybrian]

Now that's funny / ironic - I previously commented on how Mig manages such effective gas cover with such primitive diffusers - & why is'nt there anything better for critical applications - Otto / Steve was all for inventing something - seems like we were slow off the mark ! naturally these won't be available / affordable in the UK ! or made for any torch sold here - it'll be like going into a weld supply & asking about a stubby gas lens or a flex-lock torch - ( blank stare / never heard of that / been asked for one / why would you even want one !!!!!! )

[weldin mike 27]

Try these guys,

http://www.engweld.co.uk/ they seem to have lots of big brands.

PS: A guy I work with worked in england for a while, wanted some oxy guide wheels, no one had ever seen them or could sell them to him. Ended up getting his dad to send a set from Australia.

Mick

[noddybrian]

@ Mick

Thanks for the link - will have a look through their site a bit more later - but their way up the other end of the country from me & the few everyday items I glanced at seemed more expensive than I'm getting locally - & like alot of these outfits now they don't like pricing stuff unless you start an account with them & promise to buy X amount a month from them - it's a shame but Ebay has become the better option so long as you keep your eyes open - though strangely I've never found any stubby gas lenses on there.
The real problem is that BOC have a virtual monopoly - since the buy out wars a few years back where they & a couple of other companies like Esab took over all the smaller outfits & everything is now corporate they dropped established product lines we liked - doubled the prices of what was left & you never know who has made what your buying as they just badge anything as their own - the gas supply here is another example of it - their only real interest is medical gasses & users consuming gas by the tanker load - ordinary guys trying to earn a living don't interest them - but there is no encouragement to try & make anything - the only jobs that are on the up are lawyers / hair dressers / fake tan / therapists / life coaching - I could go on till my blood pressure rises - it's no wonder this country is now the sewer for any & all euro scum & Brits are emigrating to a simpler life elsewhere.

[Follow da blue light]

Thanks for the replies guys, I have to check out what is what when I start the new job next Monday....

[weldin mike 27]

@ Noddy,

Thats no good mate, Get onto a 457 visa over here, lots coming over, plenty of work. Big companies like the 457s cos they want to work. Unlike us Aussies. (dont tell anyone i said that....) Ps the search engine on bernard site listed the nearest genuine dealer of torches to england as germany.

Mick

[Follow da blue light]

I thought they made the 457 very hard to get?

[weldin mike 27]

Doesnt appear so, heard of heaps of boys getting sacked to employ overseas workers.

[nathan]

Hey,

Have a look at this, sort of like a gas lense for mig. supposedly great for alum welds.

http://www.bernardwelds.com/centerfire- ... j7NBj9aaSo

Mick

I'll be asking for a bag of these tomorrow. Man, it's amazing the stuff I learn with just one visit here every week or two!

[nathan]

Try these guys,

http://www.engweld.co.uk/ they seem to have lots of big brands.

PS: A guy I work with worked in england for a while, wanted some oxy guide wheels, no one had ever seen them or could sell them to him. Ended up getting his dad to send a set from Australia.

Mick

And what are Oxy guide wheels? Are they like training wheels for a oxy/ace torch, cause me engineer has my foreman trying to invent something like that for me.

[Follow da blue light]

[weldin mike 27]

Hey,

They will be brand specific so have a look for accessories for your torch. If ya cant find em, check ebay australia .

Mick

[nathan]

WOW! that's awesome! They want me to have something like that because the push-pull gun we have is freaking heavy; it'll give a little extra support. I'll ask for one of those on Saturday!

[Follow da blue light]

I did an update sometime ago but it didnt seem to stick so Ill try again.

I tried the gas drier but nothing changed the smut was still there.

We have just received a roll of pure Al wire and will try that with the pure Argon, the rep from Air Liquide said that a mixture of Argon and 25% Helium may help and he will send a trial bottle to us to see how it goes.

I am also going to try a bigger nozzle to see if wider gas coverage helps.

[Follow da blue light]

An update.
The pure Al wire didnt help nor did the wider nozzle, but I was very surprised at the difference the gas with 25% Helium made, there was hardly any black soot (smut), you could see the side the welder came from had non, the other side due to nozzle angle had some soot which wiped off with rag.
Ill have to educate the welder in question about nozzle angle.