Hey all - trying to accessorise my bagpipes with some fire. Running off a 250ml tank of butane w regulator, gas controlled by a solenoid and ignited currently by a small spark generator circuit which sparks roughly 10 times per second just above the output of a 6mm ID steel pipe.
However, I’m having some issues with ignition. Sometimes it ignites immediately, and sometimes it doesn’t and takes a second or two. I am only putting gas on for a second or so, often it seems to ignite as the gas is turned off. I have a theory that the gas is swamping the spark gap (the gas is certainly visible and the spark is sometimes affected as the gas comes out) - but I’m not sure how to work around this or even if this theory is definitely correct.
What I am keen to avoid is the gas failing to ignite immediately - as then it can pool down and potentially ignite my beard. I’ve seen a couple of similar designs but using pilot lights but this seems a lot less elegant and would ideally like a solution that doesn’t need constant flame. If pilot lights are totally unavoidable I am thinking of adding a temp sensor so main gas is only turned on if pilot light is on and hot. Furthermore I would like it to be reliable in a light breeze (obviously won’t use it in heavy wind).
Thanks for all the help - I know you all will have excellent ideas to make me think.
Yes, this. My oxy-propane cutting torch mixes the gases inside the nozzle (which as far as I can tell is the main difference from oxy-acetylene)
If you’re mixing fuel and air, maybe a Venturi type arrangement might work? Eject the gas through a mig welding tip into a barrel with variable air intakes and enough length to ensure mixing before ignition.
Although all this might be rubbish, because you’re after a big ball of yellow flame, not a nice hot stoichiometric mixture.
My conclusion: a pilot light would work well with this sort of arrangement. I’ll have a think and see if I can find a spark type lighter to try that. Also playing with fire is fun.
key is to mixing and flamable gas for a reliable flame if the mig nozzle idea is good … have you considered a injecting a small amount of compressed air
Very cool! I think you’re right about the pilot light - I constructed a venturi-ish setup of @tomnewsom 's design - it did help the reliability of ignition but I think to get it lighting near 100% of the time it needs so much air/mixing that it’s not yellow enough… pilot light supplies making there way over now…
After much adventure with trying electric lighting, I’ve decided to use a pilot light.
Welded a piece of 8mm aluminium tube shut, then drilled some holes in it to act as pilot light.
However, the holes are too big, (ideally, i’d like small, intense blue flames which are hard to blow out - however, the only time i get good blue flames are on max flow rate and they’re way too big for a pilot. I reckon that the holes need to be smaller, and i’m wandering how I could do it better/if anyone has ideas howto. The holes are drilled with the remains of a 0.5mm drill.
TBH at sub-0.5mm you’re moving into precision machining, chokes and so on… Your best bet would probably be to try and find an aftermarket part with a hole of the appropriate size (a quick search doesn’t suggest anything particularly useful unfortunately).
Two suggestions:
Shave down the side of some 0.5mm dia wire and partially block the hole to produce a sub 0.5mm hole (potentially with a little more turbulence due to the out-of-round hole), or otherwise partially block it.
Use fewer holes? With say a single hole you should be able to increase the pressure of the pilot light stream, make it a little more intense.
Aside - the small, intense sort of thing you’re after: is this like a butane lighter or a bunsen? I have a feeling these are achieved by introducing more oxygen. Think opening the gate on the bottom of a bunsen to get that blue flame. Maybe if you can introduce an airflow and get a decent fuel-air mix to the pilot light? Whatever the aperture size, a fuel-rich mix is going to burn softer…
(I suppose surmounting issues like this was the reason Bunsen’s burner was so successful).
How about plumbing up some sort of needle type valve in parallel with the main valve? That way the flame will always be burning, but with the main valve shut it will be a low flame (controlled by the needle valve)
