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Airco Bumblebee 250 (MA)

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  • Airco Bumblebee 250 (MA)

    Hello all,

    First I'd like to thank you guys who write in and help people with their machines. I've read every post, ( I think), concerning the dialarc machine and have learned alot about this old work horse. A little about me, I'm not a welder by trade or any other name lol, but I can melt 2 pieces of mild steel together with increasing proficiency. (One cast vise repair under my belt as well). I was given an old tombstone AC machine and discovered that I really enjoy stick welding. Most of my welding will be projects around the acreage and I'd like to make some sweet sculptures too. I've been scouring craigslist for an AC/DC machine and finally struck gold with an old Airco Bumblebee 250 MA for $52 off an online auction. $50 of gas to drive and pick it up and I've got all the welder I'll ever need.

    My first question is, can someone help me with what year this machine was built for downloading the correct pdf manual from Miller.

    I downloaded the manual starting at serial number HF839494 stock # 901-502. This appears to be correct but my stock number is different. I've got
    serial # HG001905 and stock # 1341-0269.

    My second question is what do I need to all clean up inside? It appears to have spent a little time outside or a least in a shop that gets alot of moisture build up from temp swings. I've posted a closeup pic of one of the connections showing pretty good corrosion but I'm hesitant to take them apart as it welds and I don't want to break anything if I can't get the nut off the bolt.

    third I have what I think is a capacitor foe the fan, 2 actually of 4, with a broken wire. What's the purpose of 4 capacitors for the fan?

    Any thoughts or advice on what I shoils or should not do to shine up this old girls innards would be great. I've only gotten range selector unstuck and shined up the copper plate contacts, a little love to the amperage potentiameter, and the female plugs for electrode and work to connect to. I read on here or elsewhere a guy power washed the inside of his dialarc for a restoration. I'm not going to restore this machine because I like my tools wearing work clothes but I did blow out quite a bit of dust and dirt from inside so a power wash would really get it clean if that's something I could seriously do without wrecking it. I still cringe a little thinking about doing that though...

    anyways any thoughts, advice or info would be much appreciated.


  • #2
    Here is the pictures.
    Last edited by Noobie; 07-25-2018, 03:58 PM.


    • #3
      On the broken wires, I can’t be much help at the moment, at least without more info....even then, I’m no pro.

      As far as cleaning it up....most of my gear is old salvaged junk that I’ve brought back to work. Blow it out, clear out the mud dobbers and rodent nests, make sure the input is set up correct and tight and fire that sucker up. At least see if she chooches.

      On the old info you need...I’d give Miller tech support a call, they can cross reference that stock number to the Miller model it is and tell you exactly what you need. I run a 1974 airco 3a (Miller 330 a/bp). One call solved it all. They even have a guy there that knows his way around those old machines, I think his name is Jeff. I’d have to check my notes. Very nice people. Very helpful. Clearly I’m not the original owner of this machine, but they still bent over backwards to help me.


      • #4
        Hey thanks for the response Ryan. I wasn't sure how much help miller would be on a machine this old. Good to know that they are still providing support.

        btw I did blow it out, seemed like pounds of dust came out. No nests inside and she fired up and seems to weld like a champ! Just was trying to get thoughts on how far to take the inside cleanup job before I put all the covers back on.


        • #5
          Move the knobs around make sure the old contacts are getting and dust knocked off, any obvious built up dirt and grinding dust, outside of that, I always have a hard time fixing something that's not broken. That machine will probably last longer than both of us.


          • #6
            Ok I've done all that. ( puts away the pressure washer.) Just doing a few short practice welds it welds pretty nice. I've got my parts now and I'll blow it out one more time and put the covers back on after installing the parts. Next step is mounting wheels and getting some hooks attached for the cables. Thanks again for taking the time to respond ryan!

            I'm pretty excited to actually use this old girl


            • #7
              Burn some rod man.