Good morning. I have started work on cleaning the Petromax lamp, which was identified by you as 829 (Bundeswehr). While taking it apart, I noticed that the generator is straight. Does this mean that it is a gasoline-powered model? And one more question. What does the letter B next to the model number mean? I would appreciate any answers. Greetings Stanisław
By design Petromax model lanterns are not designed for gasoline! Despite the straight (gasoline) vaporizer. Even the Bundeswehr had to admit that is was a mistake. Your lantern seems to have missed the re-building (?) of the vaporizer back to kerosene (petroleum).
OK - so while in service they re-worked them to be kerosene ? and did that involve swapping out the vapouriser top (with preston loop) or just changing the jet/needle ?
Correct, I thought this was clear with the evidence @Reinhard shared, the army order. Army's tend to efficiency, that is we need to use the same fuel for cars and lanterns, ergo > gasoline. Diesel would be better but hey who am I. So in the beginning they wanted and got straight vaporizers. But not all soldiers where handy enough and use in small not well ventilated tents, bunkers and what more, was never well thought about. So at a certain point in time they swapped the vaporizers but like always, some lanterns where already in homes and shop stores. But not only the fuel is a problem the design is too: there is no way you can shut off a burning (in the wrong way) petromax style lantern filled with gasoline. At an early age I thought my family members to use the air release screw in case of mall function.
Thank you gentlemen for your posts and suggestions. I have carefully read the contents of the military order, posted in Reinchard's entry, which you write about here.Petromax 829B petrol Interesting document. It seems that the main reason for the withdrawal of gasoline as a fuel for this model is the risks associated with using them indoors. I was a bit dismayed by the entry @WimVe about the inability to turn off an improperly burning gasoline-powered lantern. How should I understand this? When you write badly burning, do you mean leaks through leaks in some connections, or difficulty in cutting off the fuel supply to the burner?
Interesting but reinhardts article does not talk about conversions only the order to use kerosene and not petrol. I am interested to know if the German Army actually converted them in any way or just put kerosene in them.
@Knee With kerosene you can always open the filler cap and lose the pressure. With petrol or Coleman fluid you should not as you release flammable gas next to a flame. So lanterns that use more volatile fuel have a positive shutoff valve (Like Coleman lanterns)
Hello from Ireland. I would think the straight vapouriser should work fine with Kerosene considering the Primus 1020 design. Also, How many Petromax's are out there with a clogged up loop unbeknown to the owners...All you can do is try, if no joy then try a preston loop vapouriser.
This military order said that from now you could no longer use petrol,but there was no mention of the top parts of the carburettors having to replaced.This necessity was probably recognized in practice when it was noticed that the straight universal carburettor did not work well with kerosene.
Thanks for all the interesting answers. Thanks. I agree with this. So why the vent screw in the filler cap/manometer on this model?
Like @Fireexit1 explained. The vaporizer is NOT the issue for using whatever fuel, it is the design ! More volatile fuel need less heat, ergo straight vaporizer but they also work with the preston loop. Less volatile fuels work better with preston loop but with more pre heating also can do with the straight version. Both versions do not include a positive shut off valve like the Coleman type lanterns have. And yes there is always an expention: even E&G made a gasoline version which has two valves: one for the cleaning needle and one for ???
Sorry to ask this question. Does the hole in the nozzle matter when using different fuels in lanterns? I dig around a bit with stoves and there the hole for kerosene must be smaller than for gasoline.
Yes and no. Others will quote formulas etc, but I would try it "as is" with Kerosene. If it always is too rich you have your answer. As there is no space for a spirit cup you will need to get the rapid starter working with kerosene as well.
For gasoline the jets have a slightly larger orifice than for kerosene, which is e. g. the case for the Swiss Geniol or Petromax 821/523 army lanterns, which are inteded to burn gasoline (despite their design issue, as Wim mentioned). But the difference is only like a slightly worn jet for kerosene, so it will usually work. Contrary, for alcohol there is a big difference, so you will not get those lantern working with that kind of fuel without modifications.
There is space for a spirit cup, so it can be retrofitted. Even with the heat shield / baffle plate (Prallteller) mounted. And the Rapid preheater will work well with both kinds of fuel, even with alcohol.
Avoid petrol and kerosene with a burner cup. Is the way to go an explosion is not needed..good luck m8tey
I have a Petromax 2827B wartime lantern, June 1944, and that lantern was the same as the ones you see today that were issued by the modern German army in the 1960’s. I guess the lesson was not learned… I can’t believe they didn’t experience problems during the war with this concept!
The design was perfect so why change it? As for fuel choice: there was a choice for other generators in the old days, likewise the fuel types where different then.
Hello, having found this conversation my question might fit in. I have recently been working on two Petromax lamps, one 828/350 and one 829/500. Both working good now although there is one difference when shutting off. When I turn the blue wheel upright on the 828 the lamp is off immediately, like an electric lamp. When I turn the blue wheel upright on the 829 the lamp in lingering on for about half a minut and in the end shuts off with a "plop". But when I leave the lamp as it is in this way, pressurized as it is, there are absolutely no leaks, no loss of pressure. Not even the next day. On both lamps the cleaning needles are adjusted half a mm above the nozzle when the blue wheel points upright. Can anyone explain this difference i behavior? Regards, Ton.
That will likely be caused by a perfectly fitting needle at the 828, where the fuel is blocked directly at the jet, whereas the 829 shuts off by the valve at the bottom of the vaporizer (as intended), so that the remaining fuel inside the vaporizer is able to escape through a slightly worn jet besides the needle (or by a 350 needle that was fitted erroneously). Mind you that it is not advisable to store the Petromax lanterns pressurized. The needle is not intended to be a fuel shutoff, and the bottom valve is basically designed to prevent liquid fuel from escaping the jet while preheating with the Rapid torch preheater.
Exactly as what Martin had explained. Even if the footvalve is perfectly working (for now) and you've tested that the fount pressure has been perfectly holding for 24hrs, do not be tempted to regularly use gasoline, Coleman/Crown camp fuels or any other similarly volatile fuels for the Petromax 828 or 829, (regardless of whether or not, it is a 'B', 'Benzin' or Bundeswehr). I have tested Petromax founts and their footvalves similarly by pressurizing them(together with the fuel) at 3bar and leaving them aside for 3 consecutive days. No pressure drops at the end of the test period. Even with these reassuring results, the footvalve merely relies on a spring-loaded rubber pip making the seal in the NRVs. In principle, it is NOT a shut off valve. In addition, any kind of elastomeric material, including Viton, would eventually swell or shrink to some extends under prolonged immersion in gasoline. While the pips might seal well for now, they might not do so, say, a month later under similar conditions. Any kero-fueled Petromax will run with gasoline. It is just not too safe to do so.
Goodmorning, so the needle on the 828 causes direct stop while the needle on the 929 is not that tight. On the other hand, I am pretty sure now both bottom valves do their job. And leaving the pressure on is not what I normally do nor using petrol or similar fuels in Petromax lamps. Thanks for answering, have a nice sunday. Ton.
