Flash back arrestors.

[Bob]

 I just saw something on the "HHO Underground" site where Lee hangs out at, that I thought was Prudy neet.
...
its a simple flash back arrester made from a piece of 3/8" tubing stuffed real tightly with fine bronze wool from the hardware store... with nipples to reduce the pipe down to the gas line size, its about as simple as it gets.
 the one caution the guy gives is to make sure no air pockets exist in the pipe by the nipples as the Hydroxy gas can burn inside the pipe and not give you any indications except from the heat the pipe reaches while the flame is burning inside the pipe ! (he found this by testing the arrester by lighting the end with a lighter and after a few times it wouldn't light again... come to find out it was burning inside the pipe and the pipe got hot fast!)
...
the guy used what looked to be 3/8" x6" brass pipe and fittings and fine bronze wool and a rod to stuff the bronze wool in real tight.... that's it and it seamed to work very well !
...
although it doesn't beat the simplicity of the cigarette butt filter in the line it is a very good addition to the line that feeds the bubbler !
...
Bob......