Phoebus 635 NRV problem

Discussion in 'Fettling Forum' started by Scott D, Apr 7, 2021.

  1. Scott D

    Scott D United Kingdom Subscriber

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    1DA3B572-39E3-4FD0-84BE-E448D65FB699.jpeg 4A7F120F-5B9E-4AE5-8CE2-1E8DE7048973.jpeg

    I may have a problem!

    I fired the Phoebus 635 and got a decent light initially but the nrv was passing enough to be a problem. I tried to remove the valve to replace the pip and spring but the lug sheared off the top of the valve not leaving enough to be able to get anything on it. I tried an extractor but still couldn’t get it moving but after several attempts have now drilled straight through the valve so the bottom end section dropped into the fount. I think/hope I still have the upper edge and thread of the top section of the valve in the threaded hole at the bottom of the pump tube so I don’t think all is lost yet. I’m open to suggestions as to how to proceed with the final extraction, assuming there is something left to extract. (It would be a big gamble on my very recently acquired soldering “skills” being up to removing/replacing the whole pump tube). I’ve also struggled to find much info on the lamp. It looks like a typical Primus/Optimus nrv and the Primus tool fits but I need to know for certain before I make this situation any worse.

    If I do have to drill out completely, could I size and tap for a larger nrv, a Bialaddin for example?

    Of all the lanterns I’ve worked on so far it would have to be one of the rarer ones that I have my first major problem on!

    Couldn’t manage a better photo.

    Thanks
     
  2. Henry Plews

    Henry Plews Subscriber

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    @Scott D I understand your trepidation, I had not had a great deal of practice/experience at soldering when I found myself in a similar situation. Long story short, my lack of confidence was my own worst enemy, removing the pump tube and putting it back wasn't difficult at all.

    After I'd washed out the tank to remove all traces of fuel, I put it in the vice (protected with strips of soft wood) to hold it firmly. You could also hold it by the vapouriser if your vice doesn't open wide enough to hold the tank. Remove the pump leather and replace the pump rod. If you're worried about heat conducting to other fittings and softening soldered joints, wrap them in kitchen towel soaked in water. Apply heat to area around the pump tube and pull on the pump knob, make sure to pull squarely. If the tube sticks, do not wriggle it as this may enlarge the hole, just keep applying heat to keep the solder molten.
    When it comes to replacing the tube, simply line up the nickelled part of the tube with the hole in the tank. Personally, I prefer to have the NRV fitted (albeit without the rubber pip), though it's not imperitive.
     
  3. Scott D

    Scott D United Kingdom Subscriber

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    Thanks @Henry reckon you’re right. Shouldn’t be complicated in theory and I do have a recently retired Bialaddin fount I could practise on. Is it a fairly standard NRV unit in the Phoebus 635? Do you know what I need? The current one is already in pieces so I don’t have much to work from.
     
  4. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    @Scott D - I think you have the right attitude and you come across as someone who will not find this difficult, but just lack a bit of practice.
    As long as you understand a few things you will be just fine - in no particular order: a) soldering relies on making a very thin layer between two close fitting surfaces. b) capilliary action. c) the importance of clean joints and flux d) thicker solder joins does not equal better e) heat dissipates and can melt nearby joins f) excess solder can be wiped off using a damp cloth g) you can "tin" joints in advance - i.e pre-solder them seperately.

    I would practice on other things as you mention - start with a bit of copper/brass strip and work your way up.
    good luck
    Chris
     
  5. Henry Plews

    Henry Plews Subscriber

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    @Scott D the NRVs in most European lamps (and stoves) have the same thread, it's just the head that is significantly different. The NRV in my Phoebeus 645 has a screwdriver slot but I think it's a replacement, the other Phoebus lanterns have Primus type NRVs.
     
  6. Scott D

    Scott D United Kingdom Subscriber

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    Thanks guys, feeling better about it now. Will keep you posted!
     
  7. M.Meijer

    M.Meijer Subscriber

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    With a hole drilled through, that could even be enlarged with a bigger size drillbit, does it not provide purpose for a left hand extractor?
     
  8. Scott D

    Scott D United Kingdom Subscriber

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    Possibly Mike, I walked away from it the other day as it was one of those moments where frustration could have led to a bigger problem. I’ll have a look again today with a clear head, as you say it may be salvageable yet.
     
  9. Scott D

    Scott D United Kingdom Subscriber

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    A4010079-1047-4E25-9E24-7D3A3AB31AA9.jpeg Well I wish I’d done that two days ago. It seemed fairly well stuck when I started trying to pull it out but once I started twisting and pulling at the same time it slid out fairly easily. The good news is that it looks like I’ve stopped my drilling and extraction attempts just short of the pump tube thread for the most part and the body of the valve just fits through the hole and the NRV thread is wider still so I should be able to get a good enough fix to seal it. There is still some surplus metal in the threads but I think just passing a tap through it will clean it up nicely. The NRV thread is 5/16” OD, but wondered if anyone can confirm the size/pitch as I seem to have misplaced my thread gauges in the 20 years since I last used them and I’m rather hazy on thread measurements, but do remember it wasn’t as easy as sticking the verniers on the thread and reading the OD.

    Thanks again for the advice, feeling pretty confident about the Phoebus now and really pleased that I’ve actually attempted the repair!
     
  10. Fireexit1

    Fireexit1 United Kingdom Subscriber

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    So good so far - you might be able to tease out the metal with a pointy thing ?
     
  11. Scott D

    Scott D United Kingdom Subscriber

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    I’ve tried, I might need a better quality pointy thing. The o ring picks I have are rather bendy! Going to try some dental tools this time, as I remember being recommended on here somewhere.
     

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