Pmax Stresses

Discussion in 'Fettling Forum' started by isfuzzy, Jul 15, 2020.

  1. MYN

    Offline
    Joined:
    Feb 28, 2018
    Messages:
    1,507
    Location:
    Malaysia
    I made a recent search on their current website. Well, I think that still holds.
    I don't have a Britelyt to test that out but the following patent is what seems to be the origins of that lantern:-
     

    Attached Files:

  2. isfuzzy

    isfuzzy Subscriber

    Offline
    Joined:
    Feb 13, 2014
    Messages:
    124
    Location:
    Singapore
    I got to work on the Pmax collar today. Also some touch ups on the Britelyt and 150 Santrax.. I only did see the need to fill more gaps after buffing...

    Steps taken;
    1. Heat the daylights out of the collar
    2. Shape the collar... now that I got rid of the springy-ness, this step is just hammer away
    WhatsApp Image 2020-07-18 at 18.59.14.jpeg WhatsApp Image 2020-07-18 at 18.59.14 (1).jpeg
    3. Actual brazing... a hell lot easier on the Pmax since its so thin
    WhatsApp Image 2020-07-18 at 13.54.49.jpeg
    4. Wash
    5. File, sand, scour wheel, buff
    WhatsApp Image 2020-07-18 at 18.59.14 (2).jpeg
    6. Assemble

    WhatsApp Image 2020-07-18 at 18.59.14 (3).jpeg

    My honest thoughts about Britelyt.
    The lamp is definitely heftier when compared to the Pmax.. There is that tactile feel to it like everything is made thicker. Its a shame to see they did not go ahead to change the way the cage fastens to the tank. Vapalux 300X as an example. One thing here is.. Both the lamps in the pic has got Butterfly J-tube and heat washer. Also fitted with the single piece burner from Britelyt.
     
  3. WimVe

    WimVe Subscriber

    Offline
    Joined:
    Aug 3, 2011
    Messages:
    1,887
    May be me: but when Ii look at drawing 15, I wonder how fuel can leave the tank at all.
    Rod 372 can not be pushed down.
     
  4. isfuzzy

    isfuzzy Subscriber

    Offline
    Joined:
    Feb 13, 2014
    Messages:
    124
    Location:
    Singapore
    I certainly will not run other than kerosene or kero amish.. No matter how robust the claims are. There are things like the fuel cap, having the knob pressure release screw there. You might know you are running white gas in there. So you walk away, any somebody else in your group thinks its time to turn the lantern off for whatever reason. He turns that innocent looking screw full throttle.. And guess what, just so happens that the vent is facing the mantle.. :clap:

    That fuel knob thing? Was it Nitehawk lanterns having the separate positive shut-off knob and the pricker knob? Why not do that?

    The Rapid shouldn't be there either for white gas..

    Yeah... There seems to be a slight boo-boo in the Fig.15

    And this thread... Having cracks on the Britelyt collar??

    Something I want to point out while brazing the Pmax. I had to take a different approach for the Pmax collar. Instead of brazing form the inside like what I did on the Britelyt. The Pmax cracks are mostly on the outside surface. Almost none of the cracks made it to the inside of the collar. Which meant tonnes of filing thru the ridges on the Pmax collar ](*,)
     
  5. MYN

    Offline
    Joined:
    Feb 28, 2018
    Messages:
    1,507
    Location:
    Malaysia
    I've not experienced any stress cracks on the frames/collars or founts of my Petromaxes so far. They're all German mades dating from the 1930s to the 60s.
    I had a couple of both the EYE and BUTTERFLY brands that are all brass instead of the usual steel on newer ones. Not sure if they're nickel or chrome plated.
    They have a couple of stress cracks on their collars but they're not conspicuous. Therefore, I just left them unmended. On the EYE unit, there was a tiny crack at the side of its fount. I can't sil-braze it since that'd melt the solder on other areas. So I just soldered it. It held up fine so far.
    I've brazed the original vaporizer on the Petromax that had sprung a leak. That was only because I can't find a replacement and had to make it functional again. That was pretty tricky since the braze has to stand up to high operating temperatures on a pressurized part. Tricky in the sense that I need it to be strong but don't want that to be a big unsightly blob of metal on the vaporizer.:)
     
  6. MYN

    Offline
    Joined:
    Feb 28, 2018
    Messages:
    1,507
    Location:
    Malaysia
    Yeah, you're sharp. Seems a mistake in the illustration there.
     
  7. WimVe

    WimVe Subscriber

    Offline
    Joined:
    Aug 3, 2011
    Messages:
    1,887
    Well I was looking or searching for any alterations of the original design by E&G.
    Which I don't see.
     
  8. isfuzzy

    isfuzzy Subscriber

    Offline
    Joined:
    Feb 13, 2014
    Messages:
    124
    Location:
    Singapore
    @MYN
    I would think the rods I got are just phosphor-bronze. I'm not pretty sure actually because it did got the carbon steel wires stuck on solid while holding the brass pieces together in the past. I think phosphor-bronze wouldn't have done that without even minute amount of silver.. I don't know what I bought from the hardware some 98 years ago :-k

    Anyways, I had to flux the old school way of dipping hot rod into powdered borax flux.
     
  9. MYN

    Offline
    Joined:
    Feb 28, 2018
    Messages:
    1,507
    Location:
    Malaysia
    The old borax flux works well usually. Well phosphor-bronze are used in a lot general brazing, example, refrigerant copper tubes for air conditioning, chillers, etc. For instance, the brazing alloy strip Harris 0 would be phosphor bronze without silver. These are less pricey compared to their other silvered products.
    For iron/steel, you could just use brass rods with borax instead of other exotic alloys. It'll require more heat to melt the brass rods compared to silvered alloys. They're not suited for brazing on brasses since the required heat to melt the rods would be melting the workpiece as well.
     
  10. JonD

    JonD Subscriber

    Offline
    Joined:
    Apr 15, 2014
    Messages:
    771
    Location:
    Hertfordshire, England
    This is a part of brazing folk lore that puzzles me.
    If I can weld mild steel with a steel rod and an oxy-acetylene torch used very carefully - which I can.

    Why can't I do this with brass used very very much more carefully? Maybe with some flux.
    I have never tried but I am tempted to try...

    The roofers manage to do it with lead. So?
     
  11. WimVe

    WimVe Subscriber

    Offline
    Joined:
    Aug 3, 2011
    Messages:
    1,887
    Well I am not sure if the English language makes a difference but overhere, welding (what shipbuilders do) is not brazing (what railroad track layers do > thermite) is not soldering (what the lead people do).

    But when you call a Britelite lantern a Petromax, everthing is possible.
     
  12. MYN

    Offline
    Joined:
    Feb 28, 2018
    Messages:
    1,507
    Location:
    Malaysia
    In brazing, the workpiece or part does not melt with the filler rod as in welding. Brazing, is essentially a higher temperature version of soldering.
    If you're implying brazing steel using brass rods, its almost the same as any other brazings, only at somewhat higher temperatures.
    The workpiece area must be at the melting temperature of brass and coated with borax or other fluxes. That'll be bright or cherry red hot, say 800-900deg C. At those temperatures, steel surface would oxidize to black(magnetite or some iron oxides) if without a molten flux coat over it. Molten brass from the filler rod would not wet or adhere to oxidized steel.
     
  13. isfuzzy

    isfuzzy Subscriber

    Offline
    Joined:
    Feb 13, 2014
    Messages:
    124
    Location:
    Singapore
    I'm just listing these scenarios. Of which I do not know how to approach for repair...

    How to;
    1. repair crack on steel collar?
    2. repair crack on steel font/tank? steel usually has some kind of coating on the inside
    3. repair stress crack on stainless?
    4. repair leak between stainless and brass part? like in the newer Vapalux, stainless steel font with brass pump tube and filler tube.

    I guess the other headache will be the surface finish. Like in this thread, I was lucky enough the lamps were all lacquered finish. I wouldn't be comfortable if they were chrome plated or had copper plating underneath epoxy paint.

    Anyone can shed some light on the scenarios?
     
  14. MYN

    Offline
    Joined:
    Feb 28, 2018
    Messages:
    1,507
    Location:
    Malaysia
    I wouldn't have the answers for all of them:).
    For all steel parts, its usually best welded with TIG/MIG equipment instead of just brazing or soldering. Properly welded ones would be strongest of them all.
    If the original fount was soldered on all its joints, brazing would create a mess and welding would be out of the question. Soldering would be the only solution, which wouldn't appreciably damage any internal coatings.
    Its almost similar on stainless. Only thing is the right brazing alloys and fluxes. You'll first need to remove the invisible chromic oxide layer (this is passivation that prevents stainless steels from further oxidation on the stainless or the braze between brass and stainless wouldn't work. It could be removed by those hydrofluoric-nitric acid pickling solutions or mechanically. A lot of fluxes wouldn't remove chromic oxide passivation layer on stainless because its quite inert, refractory and doesn't dissolve in most chemicals.
    If its purely a stainless steel part, its better welded as for steel.
    Of course, you'd need to ascertain if its wholly stainless steel or merely chrome plated.
     
  15. WimVe

    WimVe Subscriber

    Offline
    Joined:
    Aug 3, 2011
    Messages:
    1,887
    Before you do anything find out what material is is.
    Brass, steel, steel with brass finish.
     
  16. isfuzzy

    isfuzzy Subscriber

    Offline
    Joined:
    Feb 13, 2014
    Messages:
    124
    Location:
    Singapore
    The past weekend I reflowed some areas on the collar, just above the badge. Also did more finishing touches on the previously brazed areas. I did also decide to spray on a clear coat on the collar. The same coat I spray on the hoods.
    IMG20200729125607.jpg
    Overall, I'm happy enough with the repairs. This current global situation really made me think over stuff thoroughly. Somewhat like how things used to be like 20, 30 years ago when internet buying of parts and things were not always possible.

    The 2 lamps are now repaired. The 150cp is back up high in the shelf with the other Queens, getting lit once a while. While these 2 are back into their cases.
    IMG20200729125702.jpg IMG20200729131140.jpg
     
  17. isfuzzy

    isfuzzy Subscriber

    Offline
    Joined:
    Feb 13, 2014
    Messages:
    124
    Location:
    Singapore
    While looking for leads to the Out-D L6 lantern, I came across a disturbing image of an NOS Santrax 150cp on sale.
    22019549274016_162.jpg Brand new SANTRAX 150CP.jpg

    I would be annealing the collars for any new brass pmax collars.. Anyone knows if I can do the same for chrome ones safely without the chrome peeling or burning off?
     

Share This Page