Date my Optimus 8?

Discussion in 'Optimus No:8 (version prior to the 8R)' started by Oscar Akam, Jan 21, 2021.

  1. Oscar Akam United Kingdom

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    Hello there CCS, this is my first post!

    received_991149294558939.jpeg

    I found this beauty in a bazaar in the Netherlands for 3.5 euros. I had never seen a stove like this before and was keen to get it working. In my angst to make sure it did not leak fuel everywhere on my flight home, I may have overtightened the spindle and snapped it off inside the tube… so began the restoration process.

    1. Clean up the stove.
    2. Remove the broken spindle. After several angles of attack, I managed to remove the broken portion of the spindle in my university workshop by using a flathead screwdriver driven into the brass.
    20190923_114736.jpg
    3. Replace the spindle. I drew the design up and the lovely staff at my Uni made it on their mini-CNC lathe. At this point the stove would only produce a tiny yellow flame.
    4. Peen over broken rivets.
    5. I replaced the wick, cap seal, and SRV pip. It now ran much better! I still had the issue that the spindle tube had been bent down, meaning the packing nut was very hard to get on and would restrict the turning of the spindle. In my stupidity I tried to bend it back up and ripped the tube! I rubbed some fire cement into the gap and luckily it hasn’t caused me too many issues, very rarely a tiny flame comes out of the gap.
    IMG-20200407-WA0001.jpeg
    I then used the stove on many trips, and it worked a charm. The latest addition is the wind shield I made, copying one I’d seen on the forum. After its most recent testing, it does not want to generate the same pressure as before, which is a worry. I replaced the wick again, which was slightly charred but still no luck. If anyone could help me with the following, I would be very grateful!

    - I cannot find any replacement for the teared spindle tube; can anyone help me with this? I would love to try to bend the tube so the spindle is concentric again, then perhaps braze the tear, but it seems like a dangerous move.
    - I have ordered packing tape to stop a flame coming out of the spindle, does my optimus 8 need a packing ring too?
    - Can anyone help with a rough date for my stove? I would love to know, even ballpark.

    I have spent hours trawling the CCS forum and gained so much valuable knowledge, so I thought I would share my stove progress. 20210117_151727.jpg

    Oscar
    ps. sorry for such a long post
     
  2. OMC

    OMC Subscriber

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    Welcome
    You and your no 8 have learned (?) a hard lesson, twice. Servicing brass is an unforgiving arena.

    A rough date: yours will be a challenge. ...Why? You might ask...

    It is an exception not the norm.
    The more rare aluminum case, note 1. this might contribute to dating challenges.
    Yours:
    "OPTIMUS" on cover closest to the hinge, re steel case this indicates earlier.
    Fuel inlet enters side of burner (indicating slightly later), this began c.1935 .
    I presume it's a nickel tank? and plating on tank lid closely matches the tank?
    298D tank lid :-k :-k , 298D came along closer to 1950, much later than c. 1935.

    Which... if yours is all original ... returns us to note 1... Might it be possible the aluminum cases did not change while the steel cases did change?

    Easy answer re approx. age :-k , ...for now I do not know. As narrow a range as I see is late 30s to early 50s.
    As more rare aluminum examples emerge and this dating topic is revisited, if original "maybe" we find yours dates closer to late 40's / 1950 than 1935?
     
    Last edited: Jan 21, 2021
  3. Dean

    Dean United Kingdom Subscriber

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    Welcome @Oscar Akam
    I am sure an expert will be along at some stage to advise you, but if you return to the stove reference gallery, Sweden, Optimus, Op 8 prior to 8R, where you posted your stove and thread, there are a couple (possibly more) of threads that will guide you about age. One is Bryan Miller's Pre PTC 8's and 8R's, the other Robert Radcliffe's Early Optimus 8.
    Following Bryan's thread, your stove case shows the patent number, which narrows the years (maybe) to between 1931 when the patent was granted) and 1947 (when patent expired). However, your stove sports the later type tank lid which Bryan's thread suggests was from 1950's to 1970's. Obviously, tank lids are removable and could be lost, so might get replaced by a later version, which might explain that. I see yours is a nickel plated tank and the lid matches that, which could suggest they have always been together?
     
  4. Dean

    Dean United Kingdom Subscriber

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    Looks like one may have already arrived.
     
  5. Ed Winskill

    Ed Winskill United States Subscriber

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    Welcome to CCS.
     
  6. SveaSizzler

    SveaSizzler United States Subscriber

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    Welcome to CCS, Oscar.
    Congratulations on the spindle repair. Having that kind of resource to deploy is splendid. I would have ordered a replacement part from www.base-camp.co.uk but that's too mundane. You have earned your Fettler's Merit Badge right off the bat.
    What do the Dutch [E3.50] stickers say?
    I didn't see the torn regulator shaft on first glance. It's possible the break could be sil-brazed. Member John [''Presscall''] is the resident Master here.
    It might affect Originality, but if I wanted a User stove, rather than a Collector stove, I'd look into seeing if an 8R regulator stem would fit the tank. But then the burner bell, adjustment key, spindle, internal packing and nut, self-pricker, jet [basically the whole assembly except the flame plate] would have to be swapped out. But you would have a safe srove.
     
    Last edited: Jan 21, 2021
  7. Wim

    Wim Subscriber

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    @SveaSizzler The hand written text says "needs to be checked", the printed sticker says "art & curiosities of small prices" (I'd translate it as " a & c at little cost")
     
  8. Robert Radcliffe

    Robert Radcliffe United Kingdom SotM Winner Subscriber

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    Hi Oscar, that's quite a debut! I think brazing would be the way to go to repair that tube. Another option would, of course, be to look for a donor stove.
     
  9. SveaSizzler

    SveaSizzler United States Subscriber

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    Thanks, Wim. You're the best.
    By the way. On another thread:
    Looking for a Stand and Cooking Pot
    Member Surveyor, had found Swiss Army rackstands, pans, and a pressure cooker for his BVB. Now he's searching for a related cookbook. The discussion drifted into Artillery Horse Mulligatawney, with Parsnips, and since you're a known Kartoffelkanon operator, I thought you'd be interested.
     
  10. Oscar Akam United Kingdom

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    I certainly have learnt my lesson! thank you for the information, it is fascinating to know a bit more about the history. I believe it to be exactly the same as this model - Optimus 8 - chrome tank
    although this one has a chrome tank.
     
  11. Oscar Akam United Kingdom

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    Thank you :) I think I initially did not think I could purchase them from basecamp, as I could not see a listing for an optimus 8 spindle, just the 8R. Could anyone point me to the correct spindle? Just in case.
     
  12. Oscar Akam United Kingdom

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    If I ever get the chance to get back in my university workshop I'll nosy around and see if anyone can braze it for me. I would love to get a donor stove, is ebay generally the best place to look? I don't think I'll be finding one for 3.50 this time @Robert Radcliffe
     
  13. SveaSizzler

    SveaSizzler United States Subscriber

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    Is the spindle from the [Sievert] Svea 123 [not R] the same as the early Optimus 8 [not R]?
    Base-Camp lists p/n: 2190 [Regulator Spindle for old #80 stove (limited stock)...L 10.95 GBP]
    The Primus 71 and Opti 80 were related somehow, IIRC.
     
    Last edited: Jan 22, 2021
  14. Robert Radcliffe

    Robert Radcliffe United Kingdom SotM Winner Subscriber

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    No the chances of that are slim. That was quite the bargain. I'd keep an eye out on ebay, I found France to be a good hunting ground for these stoves. Perhaps also Tradera.
     
  15. Dutchmike

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    The best hunting ground is likely Holland. But I would tell nobody of course. The alloy case I find attractive. Perhaps directly post-war with plenty of alloy but steel in high demand?
     
  16. Oscar Akam United Kingdom

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    @SveaSizzler I have heard something that the packing is the same for Optimus 8 and the svea 123 so perhaps the spindle is the same too.
     
  17. Oscar Akam United Kingdom

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    20210123_123958.jpg

    This is a pic of the flame today. I put some graphite tape in which stopped the spindle flame, and then wrapped a small bit of PTFE tape on the thread which stopped the flame coming from the tear in the photo.

    However, moments later after some minor fettling the stove will not get up to pressure. This has been happening a lot recently whereas before I have used the stove multiple times without issue, even in -4C with no problems. Anyone have any clues why it is being so temperamental all of a sudden? Thanks
     
  18. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi, have you renewed the gasket in the filler cap of the fuel tank? A hardened gasket or leaking “pip” in the Safety Relief Valve can often be the cause of loss of pressure in the tank.

    Optimus No:8R First Steps: Filler Cap & Wick

    Best Regards,
    Kerophile.
     
    Last edited: Jan 23, 2021
  19. Oscar Akam United Kingdom

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    Hi @kerophile, I have replaced the gasket and pip. It was working really well up until recently when it has started playing up. One thing I noticed is that I can't seem to get fuel to leak out of the nipple when warming with my hands or also actually creating pressure with my mouth on the tank.. maybe I should re strip the burner assembly, clean and have another go.
     
  20. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @Oscar Akam if it is a recent change in behaviour rather than a gradual one try the obvious things first:

    1..If flow of fuel is low or impeded, check that the tank has fuel ( no more than 3/4 full).

    2. Next check that the jet is not blocked...use a jet-pricker ( a stiff wire with clearance to fit a 0.23mm diameter jet.

    3. Use soapy water on all caps, joints and fittings to confirm no air or vapour leaks.

    Only when you have tried all these should you need to consider dismantling the burner .... you don’t want to break anything more.....

    Best Regards,
    Kerophile.