Hi all, I'm currently fettling an old laboratory bunsen burner, mfg. by Gustav Barthel. It works on the same principal as the other pumpless barthel gasoline burners (think Juwel 34). By the design I would put this piece in the early 1930s (cross referencing burner head and handle design with contemporary barthel blowlamps). I nearly finished restoring the bunsen, but I can't find a way to clear the jet orifice, which is blocked by a white crystalline substance. I already tried some common solvents (distilled water, ethanol, acetone, petrol/gasoline) but nothing worked. Any idea wat could have caused this white residue and how to remove it? Fallback option would be a 25ga hypodermic needle insert, but I would like to save the original jet if possible. (Pictures in a follow up post. I'm posting from my phone) regards, kk1992
@kk1992 Perhaps your Barthel is THIS pattern? If so, the jet orifice is of 0.23mm diameter. Thr jet nipple itself is large, compared here with one (top) from a Svea 123. In position on the burner. My method to clear a clogged jet is to remove it from the burner and get it up to a dull red heat, short of melting it of course (easily done, the threads deform first). Air cooled then prodded with the correct pricker. If unsuccessful, repeat as necessary. Laboratory burner, unknown encrustation, could be a spillage from one if any number of chemicals surely. John
@presscall Nice specimen! I think your bunsen is a little older (tank not yet identical with blowlamp tanks, as in later models; missing OPV in the filler cap) Funnily enough your bunsen also seems to be missing the air restrictor, seem like it is easy to lose. Took some photos of my burner, it cleaned up nicely. Should be a model 1300, unfortunately no nameplate: Your suggestion seemed sensible, so I fired up one of my smaller petrol blowtorches to put the theory to test: Tried heating the jet nipple to dull red multiple times, 0.23mm pricker didn't punch through. @ROBBO55 I already tried heated vinegar but to no avail. Might try caustic soda next, thanks for the suggestion. - kk1992
Sorry for the double post, can't seem to edit my last one. This might be slightly off topic, just as a side node regarding aspen fuel: I run all my petrol stoves/lamps/torches on alkylate fuel (aspen). This fuel is evidently very shelf stable, but today I noticed an interesting phenomenon. I always drain the founts before storing a stove, the drained fuel gets used up in my car or in my lawn mower. The little blowtorch (barthel 132) never gets drained. Because I use it regularly, it just gets topped of with fresh fuel once in a while. Today the blowtorch failed to light, even after preheating multiple times. The fuel had a rather dark yellow color, a stench of stale oil. After replacing this old fuel with fresh alkylate the torch started without any problems. Theory: Every time I use the torch only the most volatile fuel components evaporate, the heavier hydrocarbons stay in liquid form. Probably this only happened because the torch is never used for prolonged time, maybe 15 to 20min each session. Maybe I should start draining the small torch too... Self pressurizing appliances apparently need more volatile hydrocarbons than a internal combustion engine. - kk1992
I’m glad you posted it. I use the same stuff and supposed as you did that it would store indefinitely in the appliance. A pity the jet blockage didn’t respond to the red hot treatment. It must be pretty tough stuff!
Good news, the caustic soda suggested by @ROBBO55 did the trick! It was probably some anorganic salt with a high melting point. Startup was pretty easy, at full throttle it burns a little rich but if turned down a bit it runs nice and lean. Thermal feedback is somewhat questionable, it took a long time to get up to snuff. Guess the prodding with the pricker enlarged the jet orifice somewhat. Maybe I'll try a hypodermic needle insert later on, but for the moment I'm very happy with the result. - kk1992
I don't know, otherwise the jet was probably enlarged to begin with.? As alkylate fuel has got lower density than regular petrol it tends to run lean, which means that the jet would run even richer when using plain old petrol.
