timbo wrote:flame plugs? is there another term?
Illustrating the point that sparks will ignite gas as easily as open flame - If a spark wasn't enough to cause ignition in a gas powered engine, we'd need "flame plugs".
We were required to watch a demonstration when I worked for the county, on the dangers of using a grinder near flammable substances. It doesn't take much to get a solvent soaked rag to smolder, or even a spill to ignite. Just guessing, but it seems logical that the hotter sparks from a welder, or a torch pointed in the wrong direction could spell disaster.