I'm beginning to, no fully understand the comments made about the original and Chinese Petromax 829 being different. I've bought a full PX service kit to overhaul my 1962 PX 829, except nothing seems to fit!. The Rapid starter seal replacement is longer so I had to adjust the thumb lever position, now I find the lead seals are not the correct thickness!. The supplied seals are 15mm OD 10mm ID and around 2.1mm thick, unfortunately to get the generator to seal properly and tighten firmly, I have to turn it a further 90 degrees which puts the valve in the wrong place, I have tried two seals, both require the same adjustment!. The rapid starter not really an issue as the thumb lever can be repositioned where I need, unlike the main generator valve. The manometer seal is too thin so the display is now rotated to about 4 o'clock instead of 12. The new needle threads are not cut properly so I cant use it. Luckily the original is in good condition. The new ceramic burner is too small and therefore a sloppy fit, luckily I got hold of some larger diameter thread burners. Anyway, the lead seal for the generator, are there any issues with using viton O rings 10mm ID x 2mm ?. And is there somewhere that I can get the correct lead seals from or is it a case of make my own, oh and what have you done for replacement manometer seal?, what rubber can I use safely to make my own?, is TPU acceptable (Thinking 3d print a new part, minimum glass transition temp is 180 Deg C depending on the blend, but can be 220 Deg C). (TPU or Polyurethane is Paraffin / Kerosene resistant) The heat shield does not fit since the rapid burner is closer to the generator on the original PX, but nothing a dremel type tool and grinding bit can't fix. Oh actually, the spirit burner does seem to fit, so maybe not all is wrong. Anyway, first light looks to be further away as re-assembly is continuing with challenges along the way.
I've never used an O ring of any sort but if Viton will stand temperatures between -30°C and 200° C you should be O.K. Scroll down this page to item 90 Detailseite: Ersatzteil- und Zubehörliste "Petromax 500 HK, Geniol 500 HK und Hipolito 500 HK Or simply put a few turns of PTFE tape (use the gas stuff, it's thicker) round the threads, it's easy, cheap and works well. The method I use when reinstalling the valve/needle control is to start with the control in the correct position and turn it exactly 7 times. If it's still loose, back it off and put another turn or two of PTFE tape on the threads. And this affects the operation of the lantern how ? Of the many lanterns I have with a combined filler cap/manometer, there isn't a single one that sits at 12:00 when tight enough to seal correctly. Not only that but I can put the same filler cap on a dozen or more different lanterns and it will clock differently on each and every one them. Although the position doesn't affect the lantern's performance I appreciate that for some users, it is aesthetically pleasing when the dial is at 12:00. If it's of help, I've only one new unused spare filler cap seal and it's 3.25mm thick.
Thanks Henry, I've found a strip of lead this afternoon on the bay site 15mm wide by 300mm long and Code 6 (2.65mm) thick, which should allow me to make just the right thickness seal. Hopefully with me on Monday. I've definitely got a 10mm punch but not sure about the 14 / 15, but a bit of copper pipe off-cut and a hammer to create a round dent and a set of tin snips will do just what I need. I've got a brand new gauge for my other lamp to restore which when fitted to the Chinese lamp and this lamp and the AIDA with the same new manometer seal does sit at 12 O'clock, but had hoped to use the original gauge. I will try 3d printing a TPU seal and leave it in paraffin to see how it holds up. Aesthetically pleasing is always a bonus.
Lead arrived, I found a spare 15mm brass olive which cut the outside of the lead washer just perfect then with the cutout still inside the olive, I punched out the 10mm hole then pushed out the washer. Fits perfectly and has sealed the generator in tight and leak free. Lamp assembled and now sitting at 2 bar pressure test for a few hours before first light. I'm not making a show piece of this, just a good honest working lamp, so no further polishing.
Hello @chocki , the lead seals regarding the generator at the petromax works in this way: First of all you should check, how many turns you can screw the generator in the tank without seal, ending at the right position with the valve. Normally it's about seven or eight turns. Then you should screw the generator in with exactly the number of turns you figured out before. As you will see, the lead will get "floating" out at the flanks. This procedure requires to give some time to the lead for "floating" (turning step by step) and also a matching tool. Maybe sounds a little incredible but exactly that is the way, to get a correct and sustainable connection of the parts using the lead seal. Just be carefull, always screw by turning right. Never screw turning left (also not a very little) ... then it gets leaking. The other problem with the not fitting size of the ceramic burner is "by construction". New ceramic burners do not fit the old "Mischkammer" (mixing chamber, made of brass). So you have to find the old ceramic parts or otherwise you have to change also the "Mischkammer" . Hope you can get it with this explanation. Regards, Steven
For the use lead seals and washers, you've already had a good 'feel' of the characteristics. You might not always have the coincidence of getting the desired clocking positions for all the parts even if they come similarly sized as the originals. The various techniques as had been shared by members are useful suggestions. Lead is not resilient and deforms permanently. Either you get it right the first time or not at all. I've used alternatives such PTFE tape with acceptable outcomes. Might not be desirable for purists though. Alternatively, you can also use some semi-hardening/non-hardening thread sealants on the threads in combination with copper, brass or even steel washers to obtain the correct height(lower generator), desired clocking positions and a reasonably fuel-tight sealing without over torqing or tightening down too much. As mentioned, these alternatives would still work but of course, you won't get the purist's ideal on regards to originality.
Thanks all for your help and advice, I see "fetling" these lamps isn't just a case of buy an off the shelf parts kit and away you go. I wasn't looking for a purists approach, just a safe sealed joint which wont come apart at the slightest touch. These are all good solutions, I ended up making my own lead washer getting the necessary thickness needed to seal my generator into the fount. And have made another one for my next lamp.
