Restoring a Petromax 827 (newbie..)

@Martin K.
I was just thinking about that! If I try to plane the edge on the vaporizer to fit snug against the jet...since the edge looks a bit “rough” it might just help. I’ll try that tomorrow and let you know. Also got a few hooks out to get a new (used) vaporizer from some buddies.

 

@Peter ,
If the vaporiser's threads for the jet is not completely stripped and still holding the jet securely, some soft soap or copper-based antiseize compounds would seal that. Smear the sealing compounds on the new jet's thread, care to be taken not to get any into the internals. Fix it on the vaporiser and tighten sufficiently hard but not till the threads strip out. Wipe off excess. It works 99% of the time unless you are the 'lucky' 1%.

 

You might find it easier to use copper slip as a thread sealer for the jet. Stuff car mechanics use to stop disc brakes squealing. You can get a tube from any auto parts supplier so it is readily available. Probably easier to find than old fashioned bar soap. Just smear on the threads and it will seal under the heat and is also easy to unscrew after use. It is amazing stuff. You can also use it to seal the threads on a stove. I have used it many times on Primus and Optimus stoves to seal the burner threads and it seals and works fine even without using the normal heat resistant washers.

The needle screws into the end of the internal rod in the generator. So in use it is inside the generator and is self centering and is operated by turning the control wheel. I will send you a copy of the instructions for the 1940 version of your lantern. ::Neil::

 

Update.

Re-threaded the upper vaporizor with ReCoil. Seems to have worked like a charm! No leaks around the jet. Will try to start her up later today!

 

That's great, Peter.
I'd guess you've repaired that mechanically with a 'helicoil' sort of insert? Or just re-threaded the generator with a tap?
Whichever, some copper slip would further enhance the sealing. ReCoil alone would appear fine initially when unheated. But after some cycles of lighting, the thread form would assimilate a 'relaxed' condition due to some annealing or softening of the metals. The copper slip could accomodate the metal expansion and contraction from the heat cycling and maintain good sealing.
Just my thoughts.

 

@MYN

Exactly! ReCoil is the same as HeliCoil. You’re probably right about the copper sealant. Tonight I will just try to get her to light up though

 

Update.

Well. I’m doing something wrong. I had two mantels and they both look like this now. I didnt use the pre heater but the cup with some alcohol in it to pre-heat the mantle. Saw a guy on YouTube doing it just the way I did...absolutely gutted now. Aint got no more mantles and couldn’t find any but some primus 100cp at my local hardwear store....

 

This is the mantle I still got. Any chance it would work?

 

First try to get a steady blue bunsen flame without the mantle and glass, at low pressure. If you get a steady blue burn for a few minutes, then try a new mantle. The 100cp mantle will not work properly. A 300cp single tie mantle should work well. Are you sure the vaporisr is clean inside and the preston loop is clear?

 

@phaedrus42

This far i’ve just filled the cup with alcohol and fired the alcohol up. To pre heat the mantle and loop. As I saw on a vid on YouTube.
The only thing that happened was a big hole in my mantel.

 

...now that looks bad! Obviously the preheater has blown half of the the mantle away! Did you give the mantles enough time to turn completely into ash?
I'd recommend that you burn the mantles outside the lantern, maybe using some spirit, until it is completely white (except the upper rim which usually stays black).
Then before re-mounting the inner chimney with the ashed mantle (which is very soft and fragile at that time) preheat the vaporizer with full power.
After that put on the inner chimney with the ashed mantle very carefully, though quickly, and give the vaporizer another softer preheating just for some seconds, and try to light the lantern by carefully turning the handwheel. The mantle should then blow up to its final shape.

 

@Martin K.
I didn't use the preheater, just filled the small cup with some alcohol and lit it. The mantle turned all white and ashy (as I think it should?). I let it sit for a couple of hours (while making dinner) and when I was about to start it up properly I noticed the mantle was ruined.
As a complete beginner I must admit I have no idea how to start up a lamp like mine with a new mantle. I googled it and got a video showing a guy filling his cup with alcohol(?) and let it burn under the mantle for quite a while, Turning the mantle all white and ashy...then he just opened the valve and the mantle lit up. Did I go wrong letting the mantle cool down a couple of hours?

 

As the burnt mantle is extremely soft and fragile I never leave it standing for some longer time. Surely it isn't necessary to let it cool down. Only after the burnt mantle has been blown into the final shape it hardens and is much more robust. I assume that the carbonates transform into oxides and sinter to a smaller volume. However even in this state they can break easily.

 

@Martin K.
Hmmm...there’s where I went wrong then. Letting it cool down and moved the lamp around before the mantle hardened properly...will go on a quest tomorrow for a new mantle. Not easy to find (if there are any at all?!?) here on my little island...

 

Firt of all: use the right size of mantle.
second: burn the mantle to ashes and fire the lantern up. The flame front and pressure will shape the mantle and harden it.

But first make sure you get a good blue flame. So test the lantern without a mantle and globe.

 

You had two mantles that were broken the way they did in the pictures?
So, did they break because you move the lantern around, before you even turn on the fuel?
Or, did they break immediately from the initial fuel-air surge while you turn the pricker wheel?

 

Don't worry too much about the mantles now. As mentioned by other members, I would ensure that the burner is producing a steady, nice blue flame first before attaching any mantles.
Do not pressurize too much for the initial start up. And do ensure that you preheat enough before turning the pricker knob.
Air gap between the jet and the inlet of the mixing J-tube should be approximately 12.5mm for a 200/250cp lantern(no exact figures as this could vary, depending on the other conditions of your lantern).
The same thing has happened to mine before (more than once) and these things add to our experience.
Fettling a Petromax is interesting as it has many variables that we could tinker with.
Note: some mantles on the market are very inferior in quality and break very easily from the slightest jolts/bumps or strong flame surge.

 

First mante i just screwed up with. My clumsyness. Second one broke when I moved the lamp before I turned the fuel on.
Today’s project will be to start the lamp without a mantle and then, if it all looks good try a mantle again (a friend actually got one for my lamp!)

 

Don’t know if it’s possible to upload a video here. I get some kind of error message when trying.
Lamp burns with a blue flame, a bit flicker but it burns! Progress!

 

The flames seem a bit small, maybe try some more pressure. I've got a picture with a lamp that is now doing fine:

 

Just two things:
First: make sure you have single tie mantles.
Secondo:is there a air-mixture paddle in the J-tube ? At first atempt make sure it is in the vertical position.

 

The flame's blue alright. Is that too small or is it just colourless due to the pictures?
Anyway, it should be something like @Martin K. 's picture. And also, note @WimVe 's comments.
Well, freshly burnt mantles are extremely fragile. Don't move or bump the lantern while in this stage.

 

Will check the j-tube! I got a bigger flame when I pumped up the preassure a bit though.
A new problem occurred.For some reason there’s fuel coming out of the jet even though it’s in “off” position. There’s a tiny beam coming out when I start the pre-heater. Could it be that the heat from the preheater expands the fuel that’s in the vaporizer and pushing it out?
I’m not using a needle at the moment since I wrecked the only one I got...

 

@Peter look at the last indent in this post earlier, considering the foot valve.
When the needle rod is in upper position the vaporizers foot valve should be close. The rubber seal must be in good working order, otherwise at pressurizing the tank during torch preheating it will leak.
When you want to extinguish the lantern just open the air screw at the filler cap. Don't extinguish it by turning the handwheel: this will cause fuel to remain in the vaporizer which then comes out at the next preheating and cause smell and maybe flames.
You can check whether the foot valve is OK by pressurizing the tank while the excenter is in the upper "off" position. There must no fuel or bubbles come out of the jet.

 

@Martin K.
I replaced the rubber seal in the foot valve and i would say it works fine. I tried it out by unscrewing the jet, pressurised tank and turned the hand wheel. No fuel, bubbles or anything appeared looking down the pipe so I guess it’s fine?

I’ll continue my fetteling in a bit, just have to assist my daughter with her 11y party first...

 

A video file here would be a little too large to post directly, Peter. You'll need to somehow compress or zip it in some ways first.
Anyway, your lantern would work fine with new mantles when you've got the required blue flame size. The lantern would still work even with some leak at the foot valve but that'll prevent you from operating the rapid preheater torch properly.

 

When preheating fuel will expand and leak.

I am a fan of slow starting.
Use the preheater disc and alcohol,
no pressure in the tank,
air screw open > any fuel pressure will go back into the tank,

pre heat,
pre heat again,
close air screw,
pump gently and observe what happends,
flames > not enough pre heated,
gas and light > pump more until 2 bar

Enjoy the light, heat and your effort.

 

Well guys...this lamp is doing my head in...
Now I can’t get any fuel at all through the jet. Just a small “leak” (fuel coming out of the right place though). When turning the hand wheel nothing happens. And I think I was wrong saying the lower valve worked fine. It seems that it’s not sealing off the flow properly even though I replaced the “rubber thingy”.
Jet is clear of debris.

Think I’ll have to leave it be for a while ...

 

...yes, it takes a while to get things sorted if you're doing it for the first time. Sounds like the jet is blocked now, and you need a needle to clear it.
But that's a kind of a "learnig curve" everybody has done here I guess, with some help from the fellow collectors. And it's always more difficult to start with a worn or defective lantern instead of a new one that is functioning properly from the beginning.
So don't give up, and re-start from the beginning: dismantl it, look for anything that's soiled or worn, clean it or revise it until it looks perfect, and then give it a go again. These lanterns require some experience and even more patience (and of course also some money for spare parts etc.).
Good Luck, Martin