Wire Gauge for 550B Generator Wire

Discussion in 'Stove Forum' started by Scoutmaster, May 8, 2021.

  1. Scoutmaster

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    Was turing up a Coleman 550B we found buried in a troop storage box and used the blow torch cleaning method to clean out the generator. I removed the wire this time (something I didn't do on previous generator cleanings) and managed to lose most of the wire attempting to clean it. I still have the little brass elbow that hooks into the valve (and, of course, the generator tube, which is now clean but infuriatingly unusable).

    Does anybody know what gauge that wire is and what material it is made from? Has anyone ever attempted to replace the wire in one of these things before?

    I understand I can buy another generator (and I plan to pick up a couple so I have on-hand spares for the two stoves and my own personal 550B that I recently pulled out of deep storage), but if I can salvage this one, I'd like to give it a try.
     
  2. Scoutmaster

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    CORRECTION: I understand with patience I can eventually buy another generator if I get lucky. These are harder to find in the US right now than I had previously understood.

    ADDITIONAL QUESTION: Can I safely and effectively run the stove without that wire? I'm thinking its primary purpose is to help keep the generator clean, but if it also helps control fuel flow, without it am I going to find too much fuel in the burner?
     
  3. Lance

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    Scoutmaster The wire is there to maintain heat to help gasify the kerosene. Being only a little bit lighter in weight than Diesel fuel it requires additional heat and slower pressure to fully gasify. There is a very fine mesh brass or copper screen you can buy from Hobby Lobby which you can use to replace the wire. Just cut the mesh and roll it so as to fit in the generator. Don't roll it too tight but make sure it is long enough to fit across the flame pattern. This will to the same job as the wire you speak of.

    I suppose this thread should now be in the fettling forum if so feel free to move it.

    Lance
     
  4. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Still attached to the pricker wire? Or did you mean that that’s the ‘wire’ that’s disintegrated?
     
  5. Harder D. Soerensen

    Harder D. Soerensen Denmark Subscriber

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  6. Scoutmaster

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    Presscall, most of the pricker wire has disintegrated. There is a tiny bit left attached to that little brass "elbow." Was thinking perhaps that I might - and that's a big "might, I'll admit - be able to attach a new piece of wire to that elbow.

    Also - probably should have clarified that this is a white gas generator on the Scout troop's 550B. All of our other backpacking stoves are set up to run on white gas, so it wouldn't make sense to convert it to kero (although a spare kero generator for my own 550B is not a bad idea).
     
  7. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @Scoutmaster I see, so it’s the pricker wire that’s shot and not the ‘spring’ liner component that Lance was referring to.

    I don’t know the gauge, but it’s very fine. Smallest gauge wire in a stove context that I’ve used has been a guitar high ‘E’ string at around 0.23mm diameter (0.009 inches). Fine enough to clear the Coleman’s jet orifice? Maybe.

    Fiddliest task would be securing the wire to the ‘hook’ component that engages with the valve’s pricker operating cam. A lead soldered joint would be too weak and would melt with conducted heat. Silbrazing heat would vapourise the pricker wire. Crimping of some sort would work, but a tricky job.
     
  8. Lance

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    ScoutMaster where abouts is your here abouts? i'll need to check my parts board but i might have a new generator for this stove.
     
  9. Lance

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    Sorry SM i don't have one. If i had one you could have it for the cost of shipping.

    lance
     
  10. Scoutmaster

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    Lance, I'm on the Illinois side of the river across from St. Louis. I do appreciate you looking.
     
  11. Scoutmaster

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    Presscall, I need to take a close look under a magnifying lens to see how the original wire was connected, but I think it was just threaded into a hole in the brass piece.

    I just compared the pricker wire on the unmounted kero generator for my own 550B to an E-string, and the guitar string looks a tad bit too thick to the naked eye, but I'll give it a try. If it's too thick, it gives me a gauge dimension to start working down from.

    Thank you for the suggestion!
     
  12. Harder D. Soerensen

    Harder D. Soerensen Denmark Subscriber

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    @Scoutmaster
    I measured the prickerwire on my 550B (07/09) running on CF.
    Length of the wire it self is 111 mm - the end seems pointy as to clear the jet best possible.

    Thickness is around 0.32mm
    The wire seems crimped - not soldered to its fixture.
    Hope this helps a bit?
    1B44A89C-0B34-46EB-AADA-CF9DEA7658FD.jpeg CADDA89A-88E1-4846-AC67-27BAD7CE2BAC.jpeg CCFCFDCD-1C55-402C-B07D-C1FCA8DFBA45.jpeg
     
    Last edited: May 9, 2021
  13. Scoutmaster

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    Thanks, Harder. This does help.

    After pulling out the magnifying visor, I noted that mine is crimped, too. I think I can get some small brass tubing at the hobby store or online, and my wife just revealed to me that she owns a jewelry crimper. That woman always comes through at the right time in the most unexpected ways. I'm so glad I managed to trick her into marrying me.

    I went to the guitar store with the wire-less generator as well as a good one off another stove to compare, and a .10mm high E-string seemed like a pretty close fit, maybe slightly smaller. It was hard to tell looking through the magnifier and estimating.

    I don't have a clue as to how to read your measuring tool, but the fact that you have a tool tells me to trust your .32mm measurement. I will need to go back to the store and try a .32mm string; obviously, the closer I get to the original measurements, the closer I'll get to performance as designed.

    It's Mothers' Day here, so I'm going to have to push "pause" on this project and attend to my wife for the afternoon (after all, I do want to use her crimper), but I will update this thread as I make progress; this information may prove useful to others in the future.
     
  14. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Undersized is ok. It’ll still act as a pricker to clean the jet and won’t handicap performance. Too tight a clearance between pricker wire and jet orifice could cause it to snag in use.
     
  15. Harder D. Soerensen

    Harder D. Soerensen Denmark Subscriber

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    I have that E-string here as well - It seems a tiny thad thinner than the pricker wire - and it passes through jet without any problems.
     
    Last edited: May 9, 2021
  16. Scoutmaster

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    Realized I got my units of measure backwards. That E string is .010 inches, not mm. Hazards of living in a country that still hasn't gone metric 25 years after the deadline it imposed on itself 45 years ago.

    .010" = .254mm, which is much closer to the .32mm Harder measured. But if slightly smaller will still do what the original wire did, then that's one less thing I need to buy and one less trip I need to make.

    Finding the appropriate brass tubing to replace the hook at the end is the next task. Probably won't be able to get to that for another couple of days.
     
  17. Harder D. Soerensen

    Harder D. Soerensen Denmark Subscriber

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    @Scoutmaster
    I’ve been a Scout during most of my growing up years and later a Scout Leader for a period. If your fettling doesn’t work, I’ll be happy to send you my pricker wire for free.
     
  18. BradB

    BradB United States Subscriber

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    If you are forced to replace the generator and can’t find the white gas model, the 550B will burn just fine on white gas using the kerosene generator. I haven’t tried changing it yet, but I suspect the only difference between the two generators is the removable jet. I have been wanting to try putting the gas jet on the kero generator to see if it then burns the same as the “gas” generator. Using the kero generator to burn gas, the stove is very slightly less powerful. Brad
     
    Last edited: May 11, 2021
  19. Scoutmaster

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    I wanted to give you all an update. I have managed to fabricate a pricker wire for the generator.

    I used 1/16” brass tubing for the brass elbow that hooks into the valve and have experimented with both .010” and .011” (.32mm) guitar strings. The .011” is closer in size to the original wire.

    In the photo below, the new wire is on the left while an original one from the generator on another stove is on the right.

    Running into a different issue once I reassembled the stove - the valve knob doesn’t have the full range of motion it should. The stove lights and runs, but only at one setting and has more red than I’d like. Not sure if it has to do with the new pricker wiry or not. Out of time this weekend to continue troubleshooting.

    Will keep at it. Thanks again for all of the great suggestions - they really helped.

    8D7DCC5B-D9F4-4812-807E-1EA0CA1FDCEE.jpeg
     
  20. BradB

    BradB United States Subscriber

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    Have you had the valve apart? It is quite simple. You can check to see if it has the full range of motion.