Right a quick question before I pop off to bed I've finished my Primus 100, and its fine apart from a slightly uneven flame pattern it's nice and blue just a bit uneven! I've taken out the gauze and cleaned then re rolled it and inserted it back into the tube, my question is, is there a special way of rolling the gauze? Should it be loosely or tightly rolled, and can the gauze affect the flame direction? Once again I am at your mercy Thanks Ade
Hi Ade. I believe the gauze is there primarily to help vapourisation by acting as a thermal conductor/heat sink. A secondary role is maybe to trap larger particles of dirt that might have found their way into the tank, or built up as a fuel/combustion residue over time. In both cases, it probably does a better job if it's not rolled up too tight when it's inserted, though I expect it unrolls a bit and loosens off in use anyway. As to if it can influence the flame pattern. Well, what you're describing, which you've said is a 'slight' lop-sidedness in the flame (which is better than a major unevenness) is more than likely due to the jet orifice itself. I really don't expect the gauze to have any influence on it. There may be a tiny bit of grit in the jet orifice, so try running a pricker through it a few times, preferably when the stove's running as Primus instructions say (because it's more effective that way) but watch your fingers and you might burn out a pricker wire or two until you get the knack. It should be a 0.23 millimetre pricker by the way because that's the jet orifice size on a 100 (and 96 too). If it doesn't clear it it's likely to be due to a slightly damaged/distorted jet orifice. Sometimes putting a really small chamfer on the exit hole by using a twist drill held in finger and thumb (so nothing drastic, just dressing the rim of the exit hole) will straighten up the vapour stream. I've got used to this procedure thanks to having done a few lipstick burner tip insert repairs. Tip insert John
G,,day i have lightly countersunk a jet, also filed the top flat too remove pitting. both have worked. i think filing flat is possibly better as it should give closer to original shape/ spray pattern. but i have not experimented enough to say for sure. kerry
Update: Thank you soo much John, what a wonderful and well written answer to my question your link for replacing the tip left me drooling with envy I got up this morning and your answer was there, so I set about trying it out 8-[ I very gently tried a really small drill bit about 0.5mm and made a chamfer which seemed to help a little with the flame balance. I then tried a much larger bit to get a larger chamfer that wasn't so deep and which smoothed out a little of the pitting that Kerry mentioned. To cut it short, one little try it went better and another it went back to bad again, I persevered and bang I got a lovely balanced blue flame I can't thank you enough for your very helpful answers over this past few weeks And Kerry I will get some mini files to try your filing idea if ever the drill bit approach doesn't work in future.
Delighted it worked Ade and glad to help. I've realised that fixing my own stoves is one thing, but the satisfaction of helping someone out with theirs by just talking it through is just as great. Always seems to have happened on CCS and certainly before I'd started in the hobby, which wasn't so long ago at that. John
