Petromax 829B is it original?

That is what I said. But it seems that using gasoline in a Petromax is on a come back here.
Again and again people, repeat the same things here but read the safety article of NeilMcRae and make your own decisions but I would be careful with public announcements.
The name is Petromax not Benzinmax.

 

Sorry, I forgot it was you. Busy weekend.

I'll take a look at that article.

 

@Gilbert from my own experience, you can use kerosene with that straight generator but I found the lantern does not like strong blasts of cold wind. Adding up to 20% gasoline to the kero increases the volatility and gives a better burn on cold windy nights.

 

@Gilbert .I once fired up such a lantern on kerosene.Petromax 829 B runs on kerosene.
Admittedly, I did not use it outdoors, but now I will keep in mind what Henry said.
Greetings
Stanisław

 

I read the article. His final conclusion gave me a laugh. If anyone hasn't read McRaes article, at the end he said he's convinced the petromax is not engineered very well, even with kerosene.

It makes me wonder how the Col Max differed in design.

@Henry Plews, I think I'll stick with kerosene regardless and keep the straight carburetor in the case. I'll have the option to use gasoline if there is ever an emergency.

 

@Gilbert the anatomy of the kero generator is such that there is a restriction in the main tube between the two points where the loop is attached, the fuel will naturally take the path of least resistance i.e. through the loop thus giving it a little more time to fully vapourise - an ideal solution when using a less volatile fuel such as kerosene but there is no need to change the generator back to the straight one to use gasoline.

 

Will regular gasoline foul up the loop on the kero generator?

 

@Gilbert yes but only after many gallons of fuel and most, if not all, of the residue can be shifted with carburettor cleaner.

Kerosene leaves carbon which is more difficult - but not imposible - to shift but again, it will take burning many gallons of fuel before it causes enough of a build-up to have a detrimental effect on the lantern's performance.

 

I'll update you all once the lantern arrives.

I am curious about the paint. Have any of you ever seen a petromax painted from the factory? It's coming from the Netherlands if that makes any difference.

 

I think it's an extremely stupid idea to use a carburetor with a Preston loop for petrol operation. Especially not with lamps that have such a powerful rapid preheater as the Petromax.I accidentally unsoldered a carburetor coil while using the Rapid. Good thing there was no petrol in it.
I've seen preston loops that were soldered in with inferior solder,I've seen preston loops that were poorly soldered,I've seen preston loops with little holes ,thin walls and bloated by the heat.Preston loops very often glow in use,especially with 500HK lamps when they run at high pressure for a long time.

 

A good find!

 

Thanks Jeff! I hope it works well after replacing the seals and getting a kero carburetor.

Reinhard, is it worth it to re solder a Preston loop if it fails?

Will I need any special tools to completely disassemble the lantern?

 

It is not easy to completely de-coke a Preston loop vaporizer. It would certainly be easier with a straight generator(vaporizer).
In the case of modern gasolines, the rate of decomposition within the generator increases significantly at temperatures around the usual operation temperatures of these devices.
In order to reduce this rate as much as possible, there is actually a technique or an art in that. Usually, this can only be realized by the design and construction of the generator to meet these lesser known criteria:-
1. The fuel temperature within generator must only be allowed to attain a maximum value which is just slightly above the final boil-off temperature of the fuel. Anything higher is very detrimental to the fuel.

2. The residence time of any fuel that has attain the above temperature must be shortened as much as possible, and the fuel must be allowed to immediately exit the generator via the jet/gas tip orifice during operation. That is due to a nearly exponential fouling rate when the fuel is already at their vaporization temperature range and higher.

The above are very difficult to realize in actual practice.

 

@Gilbert
Look,that's all you need.
- Don't repair a carburetor,get a good used one or a new one

 

@Gilbert
Recommended video links:
youtube, King ColeMan channel and
"Restoring and Rebuilding a 1950s Petromax Lantern"
Restoring and Rebuilding a 1950s Petromax Lantern (youtube.com)

youtube, Grillshop Kiel channel and
"Petromax HK500 - Reparatur und Wartung - Schritt für Schritt Anleitung"
Petromax HK500 - Reparatur und Wartung - Schritt für Schritt Anleitung (youtube.com)

Good luck,
Piotrek

 

It usually isn't worth the trouble to 're-solder' a Preston loop generator if you're able to just buy new ones easily.
The coil or looped section is hard-soldered or brazed to the vertical part. Soft solders will certainly fail in the operating heat.
Silver-bearing brazing alloys for a higher temperature range are used for that purpose.
Not all brazing alloys are suitable. Those containing only phosphorus-copper (without silver), such as the lower cost Harris 0 or similar, which is commonly used in HVAC-R tube joints don't work well for this.
Suitable brazing fluxes(usually containing potassium salts of both boron and fluorine) are required for the job. Usually, the brazing heat is supplied by an oxy-fuel torch. It provides a more localized heating as compared to MAPP gas alone. The actual jointing is actually very brief and neat if you're already skilled on that.
Once properly done using the right alloys, the 'sil-brazed' section will not fail easily, even when you heat the generator up to dull-red. Surprising as it might sound, it doesn't re-melt as easily as a new brazing rod of that same alloy.

 

Now I am going back to college - is some braze rod "eutectoid" ?

 

Thanks for the info and link everyone.
It sounds like buying a new carburetor is the way to go.

Should I buy a new heat shield? Do you think the painted one will melt? There's no telling what kind of paint was used.

 

I'd try a paint stripper first. I can't remember if those heat shields are steel or brass, either way, they should be nickel plated.

 

I'll dunk it in acetone for a few hours.

 

There certainly are some having very narrow melting temperature ranges. Like some of those containing around 45% silver or so.

 

Is it possible to buy a carburetor by itself? Or is it necessary to buy a carburetor with the needle and valve attached?

 

Yes. You can certainly find and buy solely the 'carburetors' or vaporizers without the needle-rod assemby.

 

I'm seeing them for sale in Europe, but nothing in the US. Oh well.

 

Folk have mentioned using parts from Britelyt (who are in the US ) for things like nrvs and similar ..
I don’t know if a vapouriser from them would fit?
Other members might know??

 

I found this. I don't know if thicker brass will be better or worse, but it's a little cheaper than the whole carburetor/valve assembly.

 

@Gilbert
I do recall that some folks had successfully operated the Petromax 829B with kerosene as fuel and using the original straight vaporizer.
The Coleman 237 and the 249 are kero-fueled lanterns having straight generators.
I believe it is possible that the straight gen would also work on the 829B with kero. It might or might not require some modifications. (example: Jet/gas tip size changes, internal stuffings, coils, etc).
I would certainly give that a try in liew of the Preston loop.

 

I'll do that. Do you think I should buy a spare parts kit from Britelyt? They sell viton seals for the petromax. Would those be better than the original seal material?

 

Well I love Viton - most of the time it is superior but on occasion it can be a littler harder so might not seal when being pressed closed by a weak spring. But if you already have the other kit use those.
The thicker brass might take a little more heat to get going but is probably better and maybe even more stable than the original. Thread compatibility as well as the angles on the mating surfaces is important. Brytlit may be able to advise if it is a "drop in" or not.

 

Do you know of anyone using britelyt seals in an original petromax?

Something tells me I should stick with what is already known to work well before trying off brand parts/seals.