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Old roarer burner heads

Discussion in 'Fettlers Master Class' started by shagratork, Oct 23, 2007.

  1. shagratork

    shagratork United Kingdom Moderator Subscriber

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    I acquired a 1924 Primus No2 about two years ago.
    I finally got around to starting to fettle it this week.

    I found that the tank held its pressure but that the burner was not letting even air through.
    It was a bit of a struggle getting the roarer burner off and I had to apply some heat to the area just under the spirit cup.

    I then removed the nipple.

    I soaked the burner in a warm citric acid solution for half an hour, took it out, scrubbed it with a nail brush, rinsed it well and then back to the citric acid for another half hour and then rinse.

    No luck - the burner was still completely blocked with carbon.

    Out came the blowtorch to try the 'heat-and-quench' method.
    I usually grasp the hexagonal burner nut with mole-grips and then hold the mole-grips with a thick oven glove.
    MIsc025.jpg

    After about 10 to 12 times of heating and quenching in a bowl of cold water, lots of carbon had been loosened and expelled from the burner.
    MIsc022.jpg

    I then heated up the burner to dry out the insides and let the burner cool to room temperature.

    Next comes the 'tap-and-knock'. This involves tapping and knocking the burner to loosen the remaining carbon. In this case I tapped and knocked onto a Kleenex tissue so you could see the results.
    MIsc021.jpg

    As you will have noticed, lots more carbon came out of the burner.
    After about 10 minutes of this, I then went back to the 'heat-and-quench' method for about another 5 quenches, and then back to the 'tap-and-knock' method.

    Both released more carbon, but eventually no more carbon appeared.
    By the way, the burner is now completely clear and can be blown through easily.

    The reason I have given this account here is because I do not think that stove novices realise how much carbon can accumulate within the burner head.

    Do you get yellow flames on your 00, No1 or No5, etc? Carbon may be causing it.
     
  2. kerophile

    kerophile United Kingdom Subscriber

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    Hi Trevor, Good Tutorial and nicely illustrated.
    Please tell them not to over-do the heating to the extent that they melt the braze holding the burner together.
    I would love to see one of those patent pumps, such as Magnus showed us from the Technical Museum, in operation. How about trying a foot-pump, as well as the blowlamp on your next unblocking assignment?
    Best Regards,
    George.
     
  3. shampine

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    Great advice,Thanks !

    Shampine
     
  4. shagratork

    shagratork United Kingdom Moderator Subscriber

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    Hi George

    You are right about the overheating. A little at a time is my way.

    I know that the ideal way to clear the carbon is to push air though the burner while heating. This burns off the carbon.

    That is the recommended way from Primus and Optimus but I need to rig some way of doing it. I am looking for a suitable air-compressor. The method I outlined is a 'make do' method, which while quite effective is not the ideal.

    By the way, my photos show only half of the process.
    Once I had cleared a way through the burner tubes, I went back to the beginning and soaked the burner in citric acid, then rinsed, etc., etc., etc. I was then able to get a lot more carbon out of the burner.
     
  5. kerophile

    kerophile United Kingdom Subscriber

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    Hi Trevor, Check out this apparatus in the 1932 Radius catalogue:

    http://classiccampstoves.com/threads/202 - image 41

    You will need to go to Tesco and buy one of their workshop bicycle pumps, then modify it to fit onto the burner.

    Best Regards,
    George.
     
    Last edited by a moderator: Jul 2, 2015
  6. shagratork

    shagratork United Kingdom Moderator Subscriber

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    Hi George

    Thanks for the tip.

    I also like this setup.

    Pic.gif
     
  7. aktopp

    aktopp Norway Subscriber

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  8. spudz Ireland

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    Very true. Although I've used the 'heat-&-quench' technique on 4 burner heads to date, I am quite impressed with the amount of carbon you managed to remove from that burner. :shock: :shock:

    Great advice Trevor.

    Let's all try to keep our heads carbon free. ! :D :D :D
     
  9. barrabruce Australia

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    Thanks for the advice

    hmm Iv'e melted one burner. :D Twisted the nipple seat on another when quenching. :oops:

    Got a couple that I just can't seem to get clear enough.
    Every now and again I get enthusiastic and have a nother go.

    I tried the compessor trick. It works but you really dont need that much pressure.

    REMEMBER TO WEAR GLASSES. There will be nice little glowing soot come out then a big one every now and again. And yes they tend to blow back over you too :lol: :lol:

    Some sort of gerry rigged holding device is better than trying to balacne 3 hands at once..especilly when you get hit in the face and automatically go..ARrrrr

    Barra.
    Still hoping and trying.

    Now that Iv'e rambled on enough I'll go out and see if I can melt another one.

    :oops: :oops:
     
  10. Doc Mark

    Doc Mark United States Subscriber

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    Hey, Shag,

    Very nice stuff, Lad! You and George have offered some very important and efficacious information for us all, and it is very much appreciated!! Take care, and God Bless!

    Every Good Wish,
    Doc
     
  11. Ed Winskill

    Ed Winskill United States Subscriber

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    Computer hasn't melted, Doc?
    A good sign.....?
     
  12. Runegutt Norway

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    Why not use a ultrasonic cleaner?
     
  13. bajabum

    bajabum United States R.I.P. Subscriber

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    I have used ultrasonic, and it does remove carbon... but how much? And with my u/s unit, I can only do half a burner at a time .
    Which is better? I dunno :-s
     
  14. DAVE GIBSON United States

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    Trevor--well I'm convinced..I never tried that because i never thought that much
    could gather in the generator as it was so hot all the time..will this work on all
    stoves or just the kero burners??
     
  15. Kenh157 United States

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    QUESTION

    This is a very interesting and well thought out repair procedure.

    I think it will help me with a few of my stoves having fuel delivery
    problems.

    But my question is Is this black stuff really Carbon ? Is it an ash
    left behind from the combustion process, a fuel contaminant or
    actual Carbon ?

    Ken H.
     
  16. fyldefox

    fyldefox Subscriber

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    Hi Trevor

    This is an interesting post, and well done shifting all that carbon !

    I have just checked, and still have a 12V mini compressor, designed to blow up car tyres. It never worked very well at this but would certainly power some sort of gizmo to clear burners, when combined with a blow lamp. It would need to have some sort of heatsink fitted to provide thermal isolation between the burner and the rubber air input tube . . . . . oh no, another project to do ! ;)
     
  17. kerophile

    kerophile United Kingdom Subscriber

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    Hi, I think there can be little doubt that the substance is a petroleum coke, and as such will be pretty much 100% carbon.
    The temperatures in an operating burner are high enough to vaporise and "crack" the hydrocarbons in the kerosene feed. If you had a fractionation column rather than a jet you could separate the various fractions present in the vapour.
    I believe that a crust of pyrolytic carbon grows on the inside of the burner tubes and eventully interferes with heat-transfer and the passage of the vapour itself.
    The method which Trevor describes thermally shocks the burner and makes use of the differential expansion/contraction of metal and carbon to detach and remove this crust.

    Best Regards,
    Kerophile.
     
  18. shagratork

    shagratork United Kingdom Moderator Subscriber

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    Hi George

    The process you have just described is exactly what the heat-and-quench method does, but you have explained it much more scientifically.

    Steve, ultrasonics does work really well, but seems to have problems working within the burner tubes.

    Keith, the problems with using a compressor seem to be twofold.
    Firstly is stopping the heat transferring itself to the flexible compressor hose, and thus melting it.
    The next problem is connecting the compressor hose to the burner screw thread.
    The link to the Primus literature showing their cleaning apparatus indicates that they sold nine different burner connectors.
    Does anyone know the screw thread types and sizes of the burners??

    It may be more feasible to make some sort universal clamping device for the burners.
    Anyone got some good ideas?
     
  19. redspeedster

    redspeedster United Kingdom Subscriber

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    Trevor
    A gas Blow torch! :oops: :oops: :oops:
    Trevor is right about the heat and quench method.
    An ultrasonic cleaner will only work if the burner is only partialy blocked it needs the fluid you are using to get inside to work .
    PS. If you are buying an ultrasonic cleaner get one that heats as well makes a lot of difference.
    I use an ultrasonic cleaner as a maintenance tool, clean the crap out every now and again to prevent carbon build ups or when you need to prime more than once.
    This doesn't help with recent purchases that are already choked up though.
    Trevor can I suggest you visit Aldi when they have compressors on again, comes with a good "hobby" airtool kit: hose with quick release connectors, airbrush, inflation tools, spray gun (for those 111 cases), paraffin gun, blow off gun, tyre inflator with pressure gauge. Great deal and I'm sure we could build a rig to clean out burners to go with it.
     
  20. fyldefox

    fyldefox Subscriber

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    The first problem should be solvable by fitting an extended brass tube, which could have brass strip soldered to it to lose heat before it meets the hose connection, or run it through a water bath.

    It surely doesn't need to be a totally air tight seal, some sort of clamp fitted to the top of the burner should suffice. I'll give it some thought :-k
     

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