Veritas Superb fettle with back-burn problem

Discussion in 'Fettling Forum' started by Fireexit1, Oct 10, 2021.

  1. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Hi all.
    I think this 1954 example came to me a little "unloved". After a good soak to free up seized valve and pricker cam, some gentle cleaning and re-soldering the centre top tank nut, along with new seals and pump leather it fired up 1st time (picture 1) The elation was short lived as it soon started "back burning" and roaring (picture 2). Using the pricker allows the flame to re-form outside the burner in the mantle (with a very impressive 'pop') but reverts to back-burning in 20-30 seconds. I used a Peerless 22a mantle which formed nicely but may be a little big ? The burner gauze is in good condition, and pressure is good and not leaking.
    Any ideas on how to counter this will be gratefully recieved :-k
    C
    VT1.jpg vt2.jpg
     
    Last edited: Oct 10, 2021
  2. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    So now I have taken the burner off and cleaned inside, inspected the mesh, burner and threads - all is in reasonable condition. Put it back on with a little copper grease and used an Optimus 4a mantle. same problem persists.
     
  3. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Aha - just noticed from an earlier thread that there should be some sort of retaining clip holding the burner mesh in place. Mine is missing this, however the mesh is not dropping out, but it does maybe mean the flame can "jump in" past the edges. Sounds unlikley but it's all I can come up with at the moment. When it is working it looks fine..
    vt3.jpg
     
  4. ColinG

    ColinG United Kingdom Subscriber

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    I am not an expert but I would try a larger mantle to see if that helps. Back-burn is not something I've had to contend with in a Veritas lantern so I don't have any direct experience but a larger mantle might transfer more heat to the vaporiser/generator... maybe. This is why I keep a large stock of cheap Butterfly and no-name mantles handy so I don't mind wasting a few in tests. Also try a ball type and a larger sock type to see if either make a difference.
     
  5. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Thanks Colin. I am going to fashion some sort of retainer for the mesh, and then try a 500cp generic globe mantle. I went for the 4a as it is a 350cp globe mantle. I am also going to try and clean out the vapouriser a little more, although I can see through it well enough with the pricker removed. The fact it runs for about three minutes and then starts misbehaving might indicate poor gassification in the vapouriser once the preheat is over. Or maybe not...
    It is my first Veritas so I am on a bit of a learning curve but I must say I do like the shape of it.
    cheers
    Chris
     
  6. ColinG

    ColinG United Kingdom Subscriber

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    I've not been collecting Veritas for that long as their reputation was dire, but I've found them to be excellent lanterns... only one has ever given me bother and that was because I tried to run it without its globe!

    I've now got 9 of them - a mix of 350s and Superbs - and they're excellent... much more like Coleman lanterns than any British models and like you, I like the shape of them!
     
  7. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Progress:
    So a day in citric acid plus some brake cable jiggery for the vapoursier and a bit of springy wire from a filing cabinet folder fashioned into a clip, along with a 500CP generic mantle. NRV needed another teaking up (new lead washer fitted yesterday).
    vt5.jpg vt4.jpg
     
  8. AussiePete

    AussiePete Australia Subscriber

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    @Fireexit1
    I’m thinking that a back burn problem may be caused by not enough pressure. I would think that you’ve pressured the fount enough, but, there maybe a restriction somewhere between the pickup tube and the control valve.
    As to the Superb, I haven’t had to remove the control valve from the tank to test the flow, but @ColinG may have.
    Just thinking :-k
    Cheers
    Pete
     
    Last edited: Oct 11, 2021
  9. ColinG

    ColinG United Kingdom Subscriber

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    That's a neat fix you made from filing cabinet wire! So is it staying alight now and have you cured the back-burn? It certainly looks like you've got a good strong burn as it's very bright!

    I have taken the control valve off a Superb before but I've never had to clean out the pick-up tube. It can't be that hard but the best way to remove any tightly screwed in control valve is to hold the brass assembly in the vice and turn the tank rather that the other way round. When you reassemble it, use some anti-seize grease on the threads as it makes it much easier if you need to undo it again.
     
    Last edited: Oct 12, 2021
  10. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Hi @ColinG and @AussiePete . Thanks for suggestions/tips
    So the back-burn has stopped, but for which of the three suspected reasons we will probably never know. However I am now losing pressure so a break-down and re-fit is called for, probably with a dunk test.
    I think (but do not know) that the air is escaping via the control valve thread. No fuel leak anywhere and the pump is not being pushed out of the tube. Gland seals on the valve and pricker actuator are OK.
    I did have to re-solder the nut on the top of the tank where the valve assembly screws in as it was spinning round and round. When I had the valve assembly out I cleaned the pickup tube and the small filter on the end of it. There is a very convincing stream of paraffin from the jet.

    This lantern was is pretty poor shape so I am not surprised by the number of issues :lol:
     
  11. ColinG

    ColinG United Kingdom Subscriber

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    The way I look at it, a lantern that has been heavily used will always bear the signs of it's long working life! I've got an almost identical Superb that needs quite a lot of work so I sympathize!
     
  12. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Well we got there. A bit more (better) soldering and pressure drop stopped.

    D25643E2-381E-46C8-86F6-F6CCD08914BC.jpeg
     
  13. ColinG

    ColinG United Kingdom Subscriber

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    Hey, there she goes! It's looking great, in fact I'd say it looks Superb!

    (I'll get my coat....)
     
  14. AussiePete

    AussiePete Australia Subscriber

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    Looks like you got to the bottom of it @Fireexit1
    You’ve done a Superb job :lol:
    Cheers
    Pete
     
  15. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    Thanks chaps! It has been fun working on a different lantern. Nothing insurmountable with your help but a little different to my usual subjects. Now to clean it properly find a globe and the correct screws that hold the cap and burner base…
     
  16. AussiePete

    AussiePete Australia Subscriber

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    No worries mate. They’re excellent lanterns as @ColinG and @Norman can attest to.
    Enjoy
    Pete
     
  17. James K

    James K United Kingdom Subscriber

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    Great job, well done for persevering with it.
    These lamps do have a lovely peaceful tone when running.
     

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