I took out 5 stoves that were easy to reach, and lit them all. They are: - Original SVEA 123 (not R) - Taiwanese 123R clone - Optimus 8R (with mini pump) - Russian 8R clone - Primus 71 All of them came up with 100% blue flames. (The 71 started bad, but after pricking the jet got to a nice blue flame). What I noticed is that all of them had a disc of blue flame under the flame plate (like the one in my avatar), and in all of them the flame plate glowed cherry red after a few minutes of running. The burner bells did not get to glow. I took a whole bunch of photos, which I will upload later tonight or tomorrow. I was hoping to find at least some yellow flame tips to experiment on, but got none. I still recommend to conduct the three experiments I mentioned in my previous post (swap flame plates on bells, unscrew bell a little, make plate more concave). Yonadav
Thank you, guys, for your input. It seems that we have come an existential question about life in general . I did this yesterday and here are the results: 1) Only flame plates swapped. --> 8 R with its "bell-shaped" burner bell shows very small output; 123 R with almost catastrophic flame pattern (long, yellow flames). 2) "bad" flame plate made more concave and put back into the 123 R. --> no significant change 3) I filed the round-cornered air slots in the 123 R open a bit, so that they resembled the slots in the bell of the 8 R. --> no significant change As mentioned in a previous post in this thread the 123 R starts burning blue after being shut out for some seconds (and having cooled a tiny bit?). Soon after that flames turn red again. I have come to the end of my understanding of those burners . Since there are obviously so many bells, flame plates and combinations of them in the market I am wondering if the stove manufacturers were trying to construct "the ideal burner" simply by trial and error , with many errors out there... Regards, Philipp Aren't stoves time-consuming?
Hi, If you look through the thread, about an 1939 Primus No.71, you will see photos of the adjustable burner: https://classiccampstoves.com/threads/16107 Best Regards, Kerophile.
just to confirm one thing. If you swap the complete burner bell the problem transfers to the 8r? This is just the burner bell and cap not the jet? If Im reading this right there is something fundamentally wrong with that bell. The flames go blue if its turned off for a few seconds but upon relighting it quickly returns to yellow. A few seconds is not enough to affect the pressure in the tank. This leaves us back at something in the metal of the burner bell causing the colour. Something that is vaporising out of the metal at high heat. I would love to see a comparison of a polished spot on each burner with a tiny spot of a weak acid like vinegar applied. Bet the 123 bell discolours much faster than the 8r Wash well after doing this
As promised, here are the photos I took last night. These are the stoves I tried: As can be seen, flames are perfect blue, and the burner plates are glowing. Russian 8R clone: SVEA 123: Taiwanese 123R clone: Optimus 8R: Now I did another experiment. Took the flame plate off the SVEA 123. Got a brass coin of a similar size, held in long-nose pliers, and held it in various heights in and above the burner bell. Due to the pliers interfering with the bell rim, the coin was mostly slanted. I got all kinds of funny looking flame patterns, but ALL were 100% blue: Here I made the coin concave: Last, here is the Primus 71: My conclusions: the fault is most probably with Philipp's burner bell, although I cannot tell what it is. My gut feel tells me it is a dynamics (air/fuel mix) or heat transfer problem, and not the metal composition, but I can't prove it, of course. I will play some more with my stoves, in hope that I will be able to replicate the problem. Yonadav
All very curious. Sorry if I missed this test, but have you swapped the jets from the 8R and Svea? (Never mind, the bell swap makes that one unnecessary) Also, if you put a clean aluminum pan of ice cold water on the 123R when it is burning yellow and let it come to a boil -- is there soot on the bottom of the pan?
