Sodium Pickle Lights

A few weeks ago, the folks at the 23b hackerspace held Sparklecon, an event filled with the usual infosec stuff, locks and lockpicking, and hardware. A con, of course, requires some cool demonstrations. They chose to put a pickle in an arc welder, with impressive results.

This build began several years ago when the father of one of 23B’s members pulled off a neat trick for Halloween. With a cut and stripped extension cord, the two leads were plugged into a pickle and connected to mains power. The sodium in the pickle began to glow with a brilliant orange-yellow light, and everyone was suitably impressed. Fast forward a few years, and 23b found itself with a bunch of useless carbon gouging rods, a 200 Amp welder, a pickle, and a bunch of people wanting to see something cool.

The trick to making a pickle brighter than the sun was to set the arc just right; a quarter of an inch between the electrodes seemed optimal, but even then pickle lighting seems very resilient against failing jigs made from a milk crate, duct tape, and PVC. Video (from the first Sparklecon, at least) below.

35 thoughts on “Sodium Pickle Lights

    1. No. It’s literally just a welding arc inside a pickle.

      Electric arcs make light. Pickles are yellow/green because they filter out blue light. Result: yellow light. Surprise surprise.

      1. “When the temperature at the surface of the electrode reaches about 100 degrees C, boiling occurs. The water vapor generated locally blankets the electrode. This vapor is non-ionic and not conductive, and if sufficiently thick, current can no longer flow from that point on the electrode surface. Of course as soon as the local current flux ceases, the heating at that point ceases as well, at the area begins to cool. When the area has cooled sufficiently, the vapor blanket collapses and conduction and heating resume. At some point during the transition to or from the conducting condition, an arc is supported and light is produced.”

  1. Not really a carbon arc lamp, the pickle emits a yellow light (sodium D line) due to the excitation of sodium. You can test this by making your own pickles with other salts then sodium chloride. Potassium chloride will glow pink if I remember correctly.

    1. +1 for recognizing it’s the sodium giving the color, rather than the pickle just acting as a color filter. Copper chloride pickles would be fun too (deep green), but not something one’s likely to have in the pantry/fridge.

      1. You could easily make some. Hydrochloric Acid (sold as muriatic acid at home stores) and some ground up copper (pipe and some time with a ball mill). With enough ingenuity you could have a whole rainbow of glowing pickles.

  2. I was begining to question the brighter then the sun remark, that was until the last few seconds of the video when I almost went blind. (lime pickle hmm…)
    Defiantly amusing, after seeing this experiment done as a child I never habe been able to just walk past a large jar of pickles without at least a slight smile.

    1. It does remind me of some slow buring plastic explosive mix, all be it yellow and not purple, I think I’d have to see it side by side to tell which one was brighter.

  3. “bunch of useless carbon gouging rods”

    Carbon gouging rods are anything but useless. Ever needed to heat up 10lbs of cast steel to a nice red glow? An arc welder and two carbon arc rods held at the right relationship to each other will produce and electric ‘flame’ that can be used to heat materials. The amount of heat output rivals oxy/acetelyne torches without the dangers of storing and transporting flammable gases. My dad used one of these on a regular basis while working on cars. The ‘flame’ is really an electric arc, but when seen through a welding helmet, it really looks more like a flame than an arc. When the steel being heated looks like it’s wet on the surface, thats usually when the part is starting to reach a plastic state.

    Now if only they still made the welder attachments, I’d buy one in a heartbeat.

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