I find the brass rods quite interesting. I have a Clayton and Lambert plumbers furnace that I inserted stainless steel rods into (what I had on hand) and it completely eliminated the "chugging" that the dang thing made. My theory on those rods is that as the liquid fuel hits the hot part of the burner (coil generator in my case) the liquid fuel flashes to vapor and that expansion from liquid to gas reverberates through the pipe and pushes back any liquid, temporarily stoping any further fuel vaporization until pressure drops and the cycle begins all over again. (Vaporize, expand, push back, vaporize, expand, push back, etc) The wide open spaces of a simple pipe or tube allows this fuel vapor "pressure wave" to travel freely, but filling it with something like metal gauze or rods seems to stop that rather annoying phenomenon from occuring all together. I think the gauze and rods allow for some capillary action to act on the fuel as it has to squeeze through very narrow passages, and that capillary action aids to resist the push-back from the fuel expanding from liquid to vapor. Also, there's no more wide open spaces for the pressure wave to travel freely through, so those two forces combined smooth out the burn rate and eliminate chugging. Alright, that's enough thinking for one day
