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 K C (KalebC) - F Locale: South West Bic classic vs. Bic piezo on 04/11/2012 00:04:00 MDT Bob, I can't dispute the piezo at 19k. I often backpack in rain and snow. Try running a classic Bic and a piezo Bic under water then throw them in the freezer or fridge for an hour and then take them out and try to start a fire, this is what I tried and was very surprised.
 Bob Gross (--B.G.--) - F Locale: Silicon Valley Re: Bic classic vs. Bic piezo on 04/11/2012 00:09:35 MDT I have no plans for returning to 19,500 feet, nor do I have any plans for testing a Bic as you suggest. When up that high, the lighter lives almost permanently in my pants pocket so that it stays moderately warm and dry.--B.G.--
 Stuart R (Scunnered) - F - M Locale: Scotland Re: piezo and elevation on 04/11/2012 04:27:37 MDT What's the theory(ies) on piezo crystals at elevation? We still strike them, it still deforms and it still bursts electrons, right? Is it temp or altitude? Calibration of the air-gap? Odd.It's not the piezo, it's all down to Minimum Ignition Energy (MIE) of the gas. This is the amount of energy required to raise the air/fuel mixture to a sufficient temperature for the gas to burn. The MIE varies with temperature, pressure and air/fuel mixture. The graph below shows how the MIE for Butane varies with air/fuel mixture. The lowest MIE is 0.26mJ (at sea level and 25C) and rises sharply as the mixture deviates from the optimum.When you gain altitude, both the temperature and atmospheric pressure drop. Pressure at 10,000' is approx 70% of sea level pressure. Reducing temperature and pressure both increase the MIE - the relation with pressure is approximately inverse square law. Not only that, but as the jet in the stove and lighter is fixed, the air/fuel mixture will be richer, so the MIE will move up the right-hand side of the graph above.The spark from a piezo has a fixed amount of energy, so there will be an altitude above which the spark energy is insufficient to ignite the gas from either the lighter or stove. A 'flint' lighter will also have an altitude limit, but I'm guessing that the energy in a hot chip of ferrocerium is greater than that of a piezo spark.Reference: http://www2.galcit.caltech.edu/EDL/public/flammability/USBM-680.pdf
 Greg Mihalik (greg23) - M Locale: Colorado Re: Re: piezo and elevation on 04/11/2012 07:17:17 MDT Thank You Rob!An acronym, a graph, and an explanation. It doesn't get much better.
 Tim Zen (asdzxc57) - F Locale: MI Re: Re: piezo and elevation on 04/11/2012 10:15:13 MDT Stuart. Thanks for the facts. 15.55 grams without the labels.
 David Affleck (UtCoyote) - M Re: RE: piezo altitude on 04/11/2012 10:25:34 MDT Just from my experience as a long time cigar smoker, who frequently camps/recreates above 10,000', I've never had any luck at all with piezo ignited butane lighters at 10K. From el-cheapos that come free with boxes of cigars, to a \$125 DuPont, none of them have ever worked worth a darn. Most, haven't worked AT ALL, at 10K.- Dave
 David Olsen (oware) - F Locale: Columbia Highlands different gas on 04/11/2012 12:43:31 MDT Could one build a high altitude lighter with a different gas?Mapp gas or acetylene, propane? (I don't know the properties of each).Do carbide lights work at altitude?
 Colin Krusor (ckrusor) - M Locale: Northwest US Piezo at altitude on 04/11/2012 13:05:16 MDT I'm wondering about a larger piezo. If the spark gap were the same, but the striker and crystal were larger, the spark should be more energetic. Maybe, in the future, electrically ignited lighters will use tiny supercapacitors to produce a spark, and the capacitors will be charged by a combination of a little thin-film solar panel, a Seebeck thermocouple, and a tiny pendulum dynamo like those in some watches. For now, it seems to me that flint lighters, kept dry in a bag, are a good solution to the altitude problem.
 Hikin' Jim (hikin_jim) - M Locale: Los Angeles, CA, USA Re: Re: Re: piezo and elevation on 04/11/2012 16:18:59 MDT Thank You Rob!Here, here.HJAdventures in Stoving