Hello Wim. Possibly cleaning out the inside of the vaporizer(to nearly a shine) with a rolled piece of fine grade wet and dry sand paper, then insert a tightly rolled fine grade brass mesh along the vaporizer's entire inside length and make sure it is a tight sliding fit. The burner cone has to be a tight fit onto the vaporizer as well. Tightness is the key word when it comes to good heat conduction. As @presscall suggested, fit a diffuser plate at the top of the burner cone. Hope that helps with a better fuel vaporisation and air to fuel mixture.. John
The purring followed by flaring and repeat that you describe sure sounds like an insufficient prime. But if you're triple priming it, that should be enough. How cold is it there? Maybe try on a warmer day. Or it could be something about the mesh, as @threedots suggests. ....Arch
I would support @janders suggestion of a larger flame plate possibly sitting a bit lower into the bell. Initially I'd try bits of old tin to get the vapour flow volume going between the plate edge and the bell to optimise the gas/air mixture. I'ts certainly burning rich. You can also experiment with 'dishing' the plate down as well.
I think that the full area inside the burner cone is needed to get a better air to fuel gas ratio so if the plate is too low in that area, it probably causes a richer mixture. The flame plate does have to vent more than the total area of the holes(air intake) at the jet end of the burner cone but by how much I think it is a matter of trial and era for me. There may be a formula to work it out. A method to lean the flame to a clean blue burn on some burners is to lift the plate. That would help hasten the air drawn into the burning area through the intake holes. It would also hasten the burning flame to exit quicker increasing the heat value(BTU's). John
Hi friends, today I made a copper flame plate and experimented with its position on the bell. I started level with the bell, but got best result after bending the tabs in 2 steps thus lifting the plate away from the top of the bell. After obtaining a reasonable (but to rich) result, I first tried pumping things up but this resulted in fireballs (there is to much fuel, vap is not hot enough to vaporize it all). Lowering the pressure returned the reasonable flame. Then, I tried to get a simmering flame. Again, not a good result! That is, the first couple minutes I had a bleu & yellow flame but then again (smaller) fireballs. Again, not enough heat transferred to the vap. The size of the bell is only just a few millimeters larger than a N°96 bell. Also, the size of the vap tube is almost the same as the lipstick on a N°96. As the bell is fitted by screw-thread on the vap heat transfer should be good. This brings me to the conclusion the jet orifice needs to be smaller, closer to the size of the orifice in a N°96 lipstick. I took a couple photo's, this one is the best one: As you can see, not perfect at all, but we're getting closer! I also found the burner to be easily affected by the slightest wiff of wind. Even coughing or walking past produced more yellow..... All the best, Wim
@Wim I’m happy to resize the jet with a hypodermic needle ‘insert’. I’ll strike up a ‘Conversation’ to swap addresses. John
That's a neat flame spreader. @threedots makes an interesting observation that the air intakes are also a consideration, too small and you'll not get the fuel oxygen ratio right. The bell vents are a fixed, all the other variables are the vapour supply rate and the mixing effect dynamics the bell and plate provide. Is there then a fundamental problem with the stove design. The jet sizing is probably the culprit here in the absence of other evidence.
Hi Simon @Simes , I believe there is indeed a fundamental problem with this stove's design, basically the lack of mesh inside the vap and to large a jet orifice. Tomorrow I'll send the jet to John @presscall , who has kindly offered to do his magic trick with the jet and a hypodermic needle. In the mean time I'll try to find a decent piece of brass sheet to make a permanent flame plate (the present copper one won't last long due to oxidation in the hot flame). There's also a set of potholders to be made, and then I can show the result at Newark! All the best, Wim
Today, the jet returned home from a short holiday at uncle John's (@presscall ). While there, John did his magic trick with a hypodermic needle. During the weekend I made a brass flame plate using an old artillery shell. Different positions were tried, and in fact best result was obtained with the plate in the same (high) position as the copper one I tested before. The first photo shows the jet back where it belongs. My camera does not allow me to take sharp close-up photo's so this does not do justice to John's work. Please also note the jet does not sit in the centre of the vap.tube! The hole for the jet was drilled to one side. I would expect the hole would be drilled (and tapped) in a lathe, apparently not so! This time (as I did the testing in the shed) a single prime was used. The prime tray is approx. 20% larger than those on a N°1/N°5 type stove. I started with just a few pumps, giving things time to warm up...... .....followed by a few more strokes...... .....and then some more...... Looks good! There is still some yellow in the flames, but maybe adjusting the flame plate a bit more can solve this. Upping the pressure has to be done slowly, or one gets small fire balls. It is not until bell and flame plate are red hot the small fire balls disappear. And things do get red hot! And the last one, a view from the top! I am very happy to have found this stove, and to have been able to make it work! Special thanks go to John (Presscall) for his assistance in achieving this result. Alas, no boiling test as yet, I looked out for some useable flat iron to make pot rests, but found none that more or less fits. I'll have to cut some out of 2,5 or 3mm thick sheet. To be continued! All the best, Wim
@Wim & @presscall Nice work! That flame looks good. If it doesn’t leave any soot on your pot, it’s fine. Cheers Tony
@Wim Glad that worked, although the flame plate is exceptionally raised above the jet going by normal standards. Mind you, it’s not a ‘normal’ stove, I’ll grant! Since you’re experimenting still, I wonder if a smaller inner diameter of the plate set lower down in the burner would work better, producing a more upright flame pattern? John
A smaller dia flame plate sounds like a good idea John @presscall ! I still have a piece left from the shell so will make a smaller one to try. BTW, have you noticed the dark spot in the last photo? It is very visible it sits out of the centre. I think it is where the stream of gas hits the plate, thereby clearly showing the jet does not sit in the middle. Someone must have been in a hurry when making that vapouriser..... All the best, Wim
I see it now you’ve pointed it out. The burner plate is sometimes referred to as a ‘target’ on this type of burner I recall. If you reduce the size of the plate diameter it’d be best not to have the fuel/air jet miss the target! For a stove that seems otherwise to be of excellent quality, the off-centre tapped hole for the jet is odd, sure enough. Main thing, you have a useable flame and reliable vapourisation. It’s a stove full of character, which is what we like, yes? Bring it along to Newark please! Regards, Johgn
Hi Wim, found your post about the Maximum No1 stove. Last summer I found also one in France, also missing the top plate. Now also trie to get it work, same problems as you have. Also installed a smaller, now looking for the right diameter of the topplate.
Hi Willem @WillemZ9001B , so good to hear there is another Maximum stove alive & kicking! Later today I'll check measurements of my topplate so you can work from there making your own. I first have to catch up with my garden as we spend a week at Schouwen-Duiveland and weeds don't stop growing when one is away... Could you post some photographs of your Max? Did it come with pot holders? I made some temporary ones for mine, just to be able to use the stove. Groetjes, w!m
I checked the topplate, the circle is 40mm, the 4 "arms" or tabs are 8mm thick. As long as they're between 6 & 8mm all is fine. The plate was made out of an artillery shell (brass - messing) as copper is to soft (I did make some experimental ones out of copper just to test things as I had some copper plate at that time). As you can see from the photos, the tabs are bent so that the plate sits above the burner bell. A little experimenting is needed! As it's been many years ago since I lit this stove (2018!) I feel I need to boil some water or make coffee on it soon...
