Optimus 535 A

Discussion in 'Optimus No:535' started by dusan, Jun 19, 2016.

  1. dusan

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    Alcohol stove,run straightaway.

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    IMG_1140.JPG IMG_1141.JPG IMG_1143.JPG IMG_1142.JPG IMG_1145.JPG

    D.
     
  2. gieorgijewski

    gieorgijewski Subscriber

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  3. Funfundfunfzig

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    The 535 is one of my favourites! Nice to see the 535a variation in action! Very classy!
     
  4. dusan

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    Somethink is not in order.
    1 L boiling watter in 30 min.
    By more power flame fly simply away and die.
    ???
    D.
     
  5. dusan

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    Repair the "Wire gauze cartridge" part,No.53519

    The stove run after buy,but with low output,pumping flame and noises in tank.
    Clear direction to control the cartridge.And really,both cartridges haven hole in the middle.Bad for function.
    Repair kit : Gauze from the watercock and glasswoll.
    After repair run stove correctly ,but output is visible still low.

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    For repair

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    Repair kit

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    New cartridge

    D.
     
  6. dusan

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    Repair the Optimus 535A stove , next step.

    Finaly the right way to flawwless run found ?

    One ring between air tube and innercap open the way to more air.Selfcontrol is not enought,or out of order.
    Stove run now with high pressure,flame blast not out and FINALY HAD THE RIGHT SOUND !!!
    No more only noiseless run.
    I think too,stove run better also with higher outer cap No.1 as with original.

    IMG_1161.JPG IMG_1163.JPG IMG_1164.JPG

    End of worry? Hope so.

    D.
     
  7. dusan

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    All is others.

    With this added rings run the stove safe, but with red flame. (Little better with No.1 cup.)

    As a result of more time burning and learn harder handling run now stove correct without this added rings to.
    By priming is more heat for heel (full spirit cup) as for head and full pressure in tank needed.
    I can start this stove now every time on first attempt.
    I cook my coffee outdoors in the wind. Flame is not to see, but clear sound "sssss" is to hear. (Sweet music).
    Bee now happy.

    D.
     
  8. Kalle

    Kalle Subscriber

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    Hi Dusan,

    Nice stove you have. I have the same type of stove with it's original inner caps completely ruined.

    I improvized new ones from regular inner caps and 17x0.7 stainless steel tubing : A narrowed piece of the tubing is first silbrazed on a regular silent burner inner cap from the upper side, and then another piece of tubing is pressed to fit snugly on it from the underside (see pictures).

    535A.JPG 535A_caps.JPG 535A_flame.JPG
    By replacing different pieces of tubing, one can vary O/F ratio of the flame. I started with a short piece and kept replacing with longer one, into the point where outer cap no more developed a red glow after few minutes of run.

    The original inner caps are supposedly self-regulating in some way. I believe that they are, but I doubt they accomplish this by moving up and down as someone suggests, as there isn't any such mechanism. My guess is that air/fuel flow passing over the slit between the cap and mushroom piece draws in secondary air by venturi effect. According to Bernoulli's law, pressure drop of the effect is directly proportional to the density of passing fluid, so the denser the passing A/F mixture would be, the more air would be drawn through the slit. But this is just guesswork. If I ever use other than pure ethanol I think I need to re-adjust the tube length on my caps. I wish I just could find a pair of originals some day...

    I managed to clean clogged wire gauzes on mine, by first unwrapping, then pickling in phosphoric acid and finally re-wrapping.

    -K
     
  9. dusan

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    Hi Kalle,
    it's really the same type ?You have not the decalt on the top (only methanol) and reg.wheel with
    outher spindle is in under hole as by others petroleum stoves.
    My spindle seat in upper hole.

    D.
     
  10. Kalle

    Kalle Subscriber

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    Hi Dusan,

    Mine had decal on top, but it was half off and brittle, so I had to preserve it in transparent tape and scan it for later reproduction.

    535A_label.jpg 535A_underside.JPG 535A_burner_height.JPG

    On mine I can not fit spinde wheels into upper holes without having to re-bend the fuel lines. I have noticed at pictures of 535 kero versions too, that some have spinlde wheels seated in lowers and some in uppers. The tank feed lines must either be bent for different position or the burners must differ. In fact I myself have two different silent kero burners stamped "Made in sweden" that have near same body height buttheir spindles are at different height from the base. Alcohol burners might also come in various versions.

    -K
     
  11. Kalle

    Kalle Subscriber

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  12. dusan

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    Different,but with same problems ?

    D.
     
  13. Kalle

    Kalle Subscriber

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    You're correct. It is of interest to note that 535A comes in at least three variants, the third being a 'regular' 535 with restrictors in burners.
    -K
     
  14. dusan

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    And last.....
    Pump run total dry.
    Little bit fat is needed,now run good.

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    D.
     
  15. gieorgijewski

    gieorgijewski Subscriber

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    :)
    from 3 days - I have my own example of 535 A

    Someone fueled it - parafine or something low smelling...

    Power is low too...
     
  16. OMC

    OMC Subscriber

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    Dusan thanks for posting congrats on *success.

    Kalle, I want to thank you **specifically and welcome you to Classic Campstoves!!
    You have pointed out a destinction myself and others have surely missed.
    Ben showed us 2 Optimus alcohol burners, **you point out they are different, and I thank you for that.
    I offer 2 "Optimus" links as excellent examples that also provide additional information in support of your clever observation. Optimus info is most certainly relevant, I'll not say (just yet) the info there-in is entirely accurate.
    1972 Optimus ... Range ... catalog shows a No.209 (used on 535A) w/valve positioned higher on burner.
    1974 brochure shows a No.209N (used on a 535A etc) w/valve positioned lower on burner.
    Fellow stovies have modified optimus alcohol burners in various ways and (for me, thx Kalle, today I see) it seems OPTIMUS HAS MADE CHANGES ALSO !!!

    Dusan, *I assume Kalle's "O/F" is Oxygen / Fuel ratio? If yes, you two can "join the club" of fellow stovies
    tweeking this O/F ratio (here is link example). This has been accomplished in a variety of ways. I will add that using different alcohol fuels (brands) has been the problem on occasion (meaning the burner was not necessarily the problem, YET fix can still be adjust burner O/F ratio).
    Dusan please also note the dimples shown in that link, your rings do what Optimus's dimples are there to do. I think maybe you have done it better :content:.

    Gieorgi, Congrats on getting a 535, it is on my short wish list too.
    thx omc
    tag @z1ulike @Kalle @gieorgijewski
     
    Last edited: Jul 21, 2016
  17. gieorgijewski

    gieorgijewski Subscriber

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    @OMC This time alert do not works :(
    It is a question - "Why fuel pipes was not mounted at the bottom of the tank?"

    [​IMG]
     
  18. Funfundfunfzig

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    My Primus 535 Kerosene is one on my favourite stoves!
    image.jpeg
    The fuel pipes might have been placed in the side to keep the overall tank height to the minimum - safer from damage too!
     
  19. Jeopardy

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    Presumably they are bent down to the bottom of the tank once they get inside.
    Regards
    John
     
  20. threedots New Zealand

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    :-kI wonder about those internal caps on those Optimus alcohol burners and whether they do move up and down(even a fraction) depending on the rate of fuel being let through the regulator.
    But Bernie Dog disputed that theory and that the inner caps do not move at all.

    The oxygen level of air varies with altitude , ie...sea level having more oxygen than say at 10,000 feet up a mountain having a lot less oxygen in the air. Also air pressures change depending on altitude...
    My way of thinking is; Why didn't Optimus fix the inner cap 2 parts together with a fixed center tube and with a set air gap.

    I have had the problem with the same type of Optimus alcohol burner 'blowing out' when the regulator was turned up allowing more fuel through.
    What I did was ensure both inner cap and it's mushroom center tube (and the the outer cap) were totally clean with the mushroom cap being able to slide easily within the inner cap hole.
    It may have been a fluke that I had cleared something else when I disassembled the burner but the burner ran perfectly after all was cleaned up. :)