Primus No.4 1915 'E'

Discussion in 'Primus No:4' started by igh371, Feb 16, 2017.

  1. igh371

    igh371 SotM Winner Subscriber

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    Primus No.4 1915 'E' with, interestingly, exactly the same 'E' overstamp on a tank that had originally been made with the 1914 'D' date code as also appears on the only other 1915 No.4 on the gallery. The other interesting features on this example are an original burner with fixed flame spreader skirt all in good order, and a very nice cast trivet.
    DSC05376.JPG DSC05377.JPG DSC05378.JPG DSC05375.JPG DSC05374.JPG DSC05373.JPG DSC05381.JPG DSC05382.JPG DSC05384.JPG DSC05386.JPG DSC05387.JPG

    DSC05380.JPG

    Unfortunately not up to the tea test with this one due to continual rapid loss of pressure through a faulty but particularly recalcitrant NRV. But there is currently no rush to go further with tackling this. I now prefer a slowly slowly approach to this sort of problem rather than risking doing damage that would necessitate yet another pump tube extraction!
     
    Last edited: Feb 16, 2017
  2. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Very fine, Ian. Looks like the spirit cup is soldered to the tank top?

    John
     
  3. igh371

    igh371 SotM Winner Subscriber

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    Hi John, yes, this is the tank top spirit cup variant which was available as an option on most of the basic Primus stoves for a while around this time, but is most often only encountered on No.5s (see p.8 in the 1914 Primus catalogue). There are a few examles of No.5s with this spirit cup arrangement in the gallery e.g. I think this was possibly a response by Primus to the Auto-Optimus offering. Ian.

    @presscall
     
  4. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @igh371
    I've encountered a low-slung spirit cup before (on a No.5 as you say) but recall it just sat there and wasn't soldered to the tank top.

    I'm suggesting there's no need for it to be soldered and that in the case of your No.4 it was a user modification (to solder it) perhaps to prevent it from rattling about on the riser. The soldering doesn't look factory done in fact.

    John
     
  5. igh371

    igh371 SotM Winner Subscriber

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    Hi John, an interesting observation. I've got 3 or 4 No.5s like this, but these, and indeed all of the others I've seen, all have the spirit ring firmly fixed in position. But the amount of solder visible seems to vary quite considerably, usually it is fairly minimal such as on the linked post above or the 1st picture in this thread; this No.4, on the other hand is definitely at the greater quantity end of the spectrum! I wonder if it might have been reinforced to counter seepage from the riser joint which was never a strong point on the '0's and '4's? Ian

    @presscall
     
    Last edited: Feb 16, 2017
  6. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @igh371
    Hi Ian. Good point you make about the seepage 'cure' though it isn't characteristic of the 'classic' manufacturers to resort to tackling symptoms rather than the underlying cause, I'd have thought.

    Another good point you make and I'm inclined to think it's more to do with that. Soldering the cup to the tank would vastly improve heat conduction, especially if the tank and cup were separately lacquered before packing off to wholesalers, or when tarnishing of mating surfaces arose subsequently. That auto-start is very satisfying when it occurs on a Primus 96!

    John
     
  7. shagratork

    shagratork United Kingdom Moderator, R.I.P. Subscriber

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    There may be stoves that support this theory, but as far as the documentation on CCS shows, it looks like Optimus was responding to the Primus self-lighting stoves.
    The first mention of an 'Auto-Optimus' is in the 1915 catalogue here.
    The self-lighting Primus is shown in the 1907 catalogue here.

    SelfLight.jpg
     
  8. Tony Press

    Tony Press Australia Subscriber

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    @igh371 @ @presscall

    On the subject of spirit dishes and old Primus stove, I have:

    1 pre-1911 Primus No. 5 with a large spirit dish at the bottom of the riser (ie sitting on the tank). It is fixed.

    1 pre-1911 Primus Patent No. 5 with a large spirit dish at the bottom of the riser (fixed).

    1 pre-1911 Primus No. 1 with small spirit dish fixed to riser near the top.

    1 pre-1911 Primus Patent with large No. 1 with large spirit dish that sits on top of riser (loose). [could this be a later repair?]

    1 1911 Primus No. 1 with small spirit dish fixed to riser near the top.

    2 1913 Primus No. 1 with small spirit dish fixed to riser near the top.

    1 1916 Primus No. 1 with large spirit dish that sits on top of riser (loose).

    Cheers

    Tony
     
  9. threedots New Zealand

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    Hello Ian and nice stove.

    I have some early Primus Nr:5's and they all have their spirit dish fixed firmly onto the tank and riser except for one which I am working on now.
    That one has a damaged spirit dish and may have got knocked loose but I cannot see any trace of soldering on the underside of it so it may be a sliding fit. That is a 1915 "E" Primus Nr:5.
    It also has had a solder repair at the base of the riser so it has changed from what was there originally.

    :-k As Ian points out, the position of the soldered dish to the tank and riser may have helped strengthen a troublesome(weak??) joint at the bottom of the riser to prevent leakage there.
    Not unusual to see a little solder showing under the spirit dish from the fixed dish ones up to say 1912 from what I have seen but others are obvious repairs.
    Cheers, John
     
  10. igh371

    igh371 SotM Winner Subscriber

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    @presscall @threedots @Tony Press @shagratork - an illuminating discussion, great how so many new points can come out from sharing different views and ideas. So much more to think about now in relation to these 'self-lighting' Primus 4s and 5s:thumbup: - and there was me thinking initially that the original burner unit was the most interesting feature of this one!
    But to shift the ground a little now, another question I'm tempted to ask: has anyone actually come across a No.1 or an '0' fitted with the tank top self-lighting spirit ring? - I know they were offered, and would have thought that they would have been more obvious candidates for greater volumes of sales, but in reality they are conspicuous only for their absence from the gallery postings?
    Ian :thumbup:
     
  11. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Not on this pre-1911 '0' restoration project.

    IMG_4244.JPG

    John
     
  12. igh371

    igh371 SotM Winner Subscriber

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    Now answered own question about whether there are any No.1s with the low cup to be found in the flesh - here.
     
  13. shagratork

    shagratork United Kingdom Moderator, R.I.P. Subscriber

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    Ha! Slowly but surely more information emerges.
     
  14. Tony Press

    Tony Press Australia Subscriber

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    I’m adding one more datum to this discussion.

    I have a 1912 Primus No. 4 with the spirit cup firmly soldered to the stove at the bottom of the riser.

    E47CB34E-696F-4940-BC44-C0D2E15D4E8D.jpeg

    Cheers

    Tony

    @igh371 @shagratork @presscall @threedots
     
  15. igh371

    igh371 SotM Winner Subscriber

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    Excellent, Tony; I am increasingly intrigued by this form of auto-lighting set up. It can work! (but only if well away from drafts). When it works, however, I think the most interesting thing is that it doesn't seem to provoke underburning in the way that a normal high level priming ring would. I still can't quite work out why!
    Ian:thumbup:


    @Tony Press
     
  16. Tony Press

    Tony Press Australia Subscriber

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    Ian

    Unfortunately I can’t test the underburn question on my No. 4 because it has a roarer burner fitted, not the silent. :(

    Cheers

    Tony

    @igh371
     
  17. Rangie

    Rangie Subscriber

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    I hadn't considered that but you're right! most odd.

    Alec.
     
  18. Radler

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    @igh371
    Why no underburn occurs?

    I am studying a JUWEL 15 auto-lighter at the moment and made the following observations:
    As long as the priming flame is alight, the jet stream is relative slow and takes the flue gas of the priming flame into the mixing tube. There is not enough oxygen in the mixing tube and the burner for underburning. Only after the stream has left the burner holes, some fresh air is available.

    What is the advantage of a self-lighting stove? It is not necessary to wait for the right moment to light and you can't miss it. This is nice so far.
    The disadvantage is the smell. Not all vaporized kerosene is burnt during the priming process. This makes a lot of bad odours which are really unpleasant. If the stove is left alone unlit, it will spill vaporised or liquid fuel out of the jet for a while. Maybe the stove should have a lighter tube, to make lighting a bit more reliable.

    Best regards
    Radler
     
  19. igh371

    igh371 SotM Winner Subscriber

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    Glad to know I'm not the only one to have noted the problem of the smell as well as the extreme vulnerability to draughts. Pondering over a No.5 with this type of auto-light I previously wondered "a bit smelly in the priming phase which maybe [is] why they were eventually dropped from the range" (here). So why didn't this type of lighting up system last in production, draught vulnerability or smell, or both!
    The Svea flame 'leader' and later Primus tube type both work well in saving using the extra match, but for a true auto-light the only one I have found can really be relied upon is the Pyro Patent.
    Ian:thumbup:
     
  20. Simes

    Simes Subscriber

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    Nothing against our parents/granparents generation but would they have really.been concerned as we are of a bit of a paraffin smell at that time? They were probanly trying to heat bath water in a room that smelled of coal smoke with a tin bath sitting on a rug that gets beaten once a year if it was lucky.

    Smell, what smell?