Recently I found a 1916 copy of "Automobile Welding With The Oxy-Acetylene Flame" which briefly mentions shop-sized acetylene generators, the basics of which are: The generator should have a capacity of 1 gallon of water for each pound of carbide, a means to prevent a pressure greater than 15 psi, automatic control of feed mechanisim, water valve to prevent return of flame into generator, filtering devices to prevent dust or dirt getting into flame, and the generator should not be called on to deliver more than 1 cubic foot of gas per pound of carbide per hour. It also says that if generated too quickly, the gas is heated excessively and when acetylene reaches a critical temperature it ceases to be acetylene and becomes a mixture of gases, giving a flame that is not suited for welding steel. Mike