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MIG welding aluminum - black residue

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  • johnny_waz
    replied
    Originally posted by tigman250 View Post
    one more thing, try pushing the puddle, pulling always produces alot of soot pushing reduces it greatly.
    Exactly!
    I also found using a bigger gas nozzle produces less soot with my cobramatic(not sure you can use bigger gas nozzles with your setup?). And, block all wind/breeze or it blows your shielding away.

    Leave a comment:


  • aametalmaster
    replied
    Even i learned from the article. I just welded 4 alum columns that were formed from 16 ga sheet alum to a cast base that was only like .100 thou thick. I lowered my stickout putting the nozzle closer and straighten up my gun position a little and the welds came out shiney. Guess i was also getting "suckback" as described in the article on my earlier welds and i have been doing alum spoolgun welding for 30+ years...Bob

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  • grumpy42
    replied
    Originally posted by aametalmaster
    Great link. Thanks.

    Good to know that it is normal. After doing some experimentation I finally realized that the amount of smut deposited is dependant on the angle of the gun. I was pushing the puddle but I also wasn't holding the gun vertical to the direction of travel so I was creating rather large streaks of smut.

    All of the descriptions of spray transfer of aluminum that I had read, had described the process as "clean", so, due to my lack of experience, I was a little surprised by the mysterious black residue. I also could not think of where it would come from - it was certainly surprising to find out that the black smut is actually aluminum oxide.

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  • aametalmaster
    replied
    Weld Smut...Bob http://www.thefabricator.com/Aluminu...cle.cfm?ID=554

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  • phaxtris
    replied
    the black residue is standard opperation, pushing however creates less black soot

    Leave a comment:


  • tigman250
    replied
    Originally posted by grumpy42 View Post
    Thanks for the replies. Being new to this I really don't know what to expect.

    I was just concerned since we seemed to be getting a slightly different result from the first time we tried the machine and the only change was the new argon. Perhaps it was just the alighnment of the stars.

    So since there is nothing to worry about, we can move on to ruining more metal - and we can't even blame it on the equipment
    one more thing, try pushing the puddle, pulling always produces alot of soot pushing reduces it greatly.

    Leave a comment:


  • hankj
    replied
    Grumpy,

    Don't feel picked on. Sometimes, we (us old farts) forget to notice the number of posts that an OP has.

    Believe me when I tell you that when I joined this forum, I was greener than healthy grass. I got where I am now (some may wonder if that's a good thing! ) through a lot of ruined steel and aluminum, a healthy respect for advice from knowledgeable folks, who proliferate these forums, and membership (and participation) in these on-line wonderful knowledge repositories!

    We all gotta start! Hang in, and keep the questions coming.

    Hank

    Leave a comment:


  • grumpy42
    replied
    Thanks for the replies. Being new to this I really don't know what to expect.

    I was just concerned since we seemed to be getting a slightly different result from the first time we tried the machine and the only change was the new argon. Perhaps it was just the alighnment of the stars.

    So since there is nothing to worry about, we can move on to ruining more metal - and we can't even blame it on the equipment

    Leave a comment:


  • KB Fabrications
    replied
    Originally posted by grumpy42 View Post
    When MIG welding 1/8” aluminum I am getting a lot of black residue (carbon?).
    ROFLMAO. Welcome to the club. Good answers so far. Just wait until you are doing some GTAW and you dip your tunsten into the puddle or shove your filler rod onto the hot tungsten while you are welding.

    Leave a comment:


  • hankj
    replied
    No sweat. Happens to me all the time. A rag gets rid of it!

    Hank

    Leave a comment:


  • grumpy42
    replied
    Originally posted by tigman250 View Post
    i assume you are running 5356 alloy?

    if the soot really bothers you try some 4043. it is very common with 5356 and it dosen't hurt anything, it's just a PITA to wipe it off all the time
    I forgot to mention that we are using 4043.

    Leave a comment:


  • tigman250
    replied
    i assume you are running 5356 alloy?

    if the soot really bothers you try some 4043. it is very common with 5356 and it dosen't hurt anything, it's just a PITA to wipe it off all the time

    Leave a comment:


  • grumpy42
    started a topic MIG welding aluminum - black residue

    MIG welding aluminum - black residue

    I am back with more aluminum welding questions, but this time MIG welding aluminum. When MIG welding 1/8” aluminum I am getting a lot of black residue (carbon?). The weld bead looks nice and shiny and is surround by line of oxide, but around that is about 1/4" of black residue. The residue is easily wiped off with a paper towel.

    Being new to welding, this may be entirely normal, however, when we first got the machine (MM252 w/ spoolmatic 30A) we tried MIGing some aluminum using our TIG argon and there was not nearly as much residue. We originally used the recommended setting of 19V which seemed to be enough for spray transfer to occur. Now, we needed to increase the voltage to 20.5V for spray transfer to occur. The only difference that I can think of is that we just received new argon.

    My first thought was contaminated Argon, but we attached the spoolgun to the tank we use for TIGing and we got the same results. I used that same tank to do a couple of beads with the Dynasty and things seemed fine (shiny bead, good cleaning, no mysterious residue). So, I am starting to doubt that it is the Argon.

    Also, the metal has been cleaned with a stainless steal brush and wiped down with acetone. We have tried argon flow rates of 25-35 cfm.

    Thanks
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