THIS thread started by @Mark Layman got me thinking. My fettling of a Nova+ put me in the happy position of having the two fuel bottles charged respectively with white gasoline and kerosene, perhaps optimising one or the other stove (well, just its jet nipple) to burn kerosene more cleanly. I chose this Nova, fuel bottle already marked up. Here’s that Nova with an unworn jet on premium kerosene. Usable, of course, but I believed it would be possible to achieve optimum combustion with a reduction in the jet orifice diameter of a spare jet nipple. I’ve been using a hypodermic needle insert technique I devised for a good while now, mostly to bring worn ‘lipstick’ vapourisers back to spec but on jet nipples also. This needle has a bore of 0.25mm, outer diameter 0.45mm. Usefully, there’s still clearance for a Nova pricker in the needle bore, so I could still use the magnetic pricker, which is a useful feature to retain. A short length silbrazed into the jet orifice. More obvious from the rear. Pricker tried for size. The burn’s a lot cleaner, from simmer through to max. Here I tried out the jet pricker function. Clearance being less, the flame was extinguished on one pass. John
Thanks, John. Not having your skills, I turned to having two flame plates for my new Nova: a higher one for kerosene and a lower one for white gas. Not sure how this compares to changing jet size. Brad
@BradB Yes, I read your post added to the Mark Layman thread Brad. Hey, it’s whatever works right? Raising the plate increases the distance/time which the vapourised jet of fuel has to enable it to mix with air, bringing the kerosene mixture nearer to optimum. John
Hi, and sorry for digging up an old thread. @presscall would you mind sharing some details on your silbrazing technique please? What kind/alloy of braze did you use exactly? Did you add a flux of some kind? How did you shorten the needle? I've been trying to rejet my Nova with similar looking needles. My braze just won't stick to them. I used a jeweller's silbraze, which I think contains mainly silver, copper and zinc. My flux is borax. Tried to remove any oxide or dirt with sandpaper around the needle before brazing and cleaned the original jet orifice with a suitable drill bit. I'm wondering if I need a different braze and/or flux. -Mikko
I wonder what your heat source is. It needs to get the workpiece hot enough for the silbraze to melt and flow when it touches it (having applied the flux beforehand). It’s essential the surfaces to be joined are clean, but an abrasive risks leaving a dust residue. I use a small rotary wire brush in a Dremel at a low speed, a small buffing wheel (also Dremel) and metal polish. Sometimes all three, more often one. Your silbraze and flux are ok. John
Thanks for your input. I'm using a small propane torch so heating the nipple and needle shouldn't be an issue as the braze flows easily on the nipple. I think you're probably right with the emery residue being the problem.
Interesting to hear about increasing the distance to the flame plate for kerosene. Could anyone post a link to more info on this? I have a spare flame plate lying around.
