The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com More Quenched Gap Experiments 3/4" Diameter Tungsten Dual Hydrocarbon Quenched Spark Gap Tests using 3.5" Stainless Steel Disks with paper washers for spacers 9 series, roughly 1000V across the gap... Appearance of oxidation of sparks on the disks 3/4" Diameter Tungsten 2-Series Quenched Hydrocarbon Spark Gap Test Trial and errors using filtration media (cellulose/polyester) Paper media washers soaked in turpentine used as dielectric Appearance of soaked washer Testing on low power After ignition soot forms in the gap...which is easily cleaned with paper towels.