Thursday, January 19, 2012
Gas Terminology Translation
In North American (Canada and the US) - we mostly run our torches on Propane or Natural Gas.
For those in Europe who are wondering what the heck natural gas is: Natural Gas is a piped gas - part of the utilities (like water and electricity) - and not necessarily available outside of major urban centres. It is about 90% methane.
Butane is what we fuel cigarette lighters with. Also - some of the small torches for brazing and soldering run on butane.
Propane is sold in tanks, or delivered to large tanks for those using it - mostly in more rural areas - for home heating, cooking or industrial applications.
Propane is stored as a liquid in the tank, and what you are burning is the vapor as the gas evaporates. (But is sold in pounds - i.e. a 20 lb tank.)
Propane burns at about 50 degrees F hotter than natural gas - which doesn't sound like much.
But - my experience is - you can melt the glass a lot faster with propane than natural gas. The propane makes, for want of better terminology, a "denser" flame - it seems to transfer the heat more efficiently. The difference, all else being equal - is quite dramatic.
I also have experienced far less problems in "scorching" or "burning" the glass when working low in the flame with propane than natural gas. I can work far closer to the torch face with propane than with natural gas. If I get down close to the candles (those blue fingery parts of the flame coming directly off the torch face) - with natural gas, I'm more inclined to get grey smokey effects in the glass.
I have certainly heard some lampworkers comment about being careful of propane because of built up of contaminents in the tanks and hose - and it may have been in the past that the quality control for propane was not as good - but I have never had a problem personally.
Propane is scented to make it easy to find leaks - the resulting scent is very distinctive - I find it nauseating - but you should never smell it - the burn from the torches is very clean.
One other thing to remember - propane is heavier than air, so if it spills, it will sink to the ground. When you plan your studio space - think about this. So, if you are setting up in a basement - look for floor drains. Leaked gas could conceivably "fall" to the floor, flow into the drain and accumulate. If there is an electric sump pump in the drain to keep the water levels down, when it starts - electric motors can spark and "whomp" - potential for explosion. (Natural Gas is neutral - it just mixes.)
Likewise - look around for gas-fueled furnaces, water heaters, with a pilot light.
Some of the smaller, portable torches like the Hot Head and the Fireworks will run on a MAPP gas canister - for as long as those continue to be available. (They are being phased out here). MAPP gas is a propane blend - it has added ingredients to make it burn hotter. Mostly it gets sold in small containers for light welding and soldering and hooking up to portable equipment, like camping stoves. (They will also run on propane.)
I don't pretend to be an expert on this - just throwing some info out there for you to think about. If you want an expert - read Vic Henley's articles in the glass community magazines.
Oh, which do I prefer? Propane - I would rather melt with propane - but natural gas has the advantage of being delivered in a pipe directly to your studio and you never run out.
Well - that turned into a sort of brain dump - hope someone finds it helpful though. ;-)
PS - if you have some info about the gas used in your country - leave a comment!