From DT Online
Brazing Hearths are usually at bench height and provide a convenient, heat proof and shielded location for Hard Soldering and Annealing. They are used in combination with a Blow Torch fuelled by natural gas, and for which they may have a built-in air compressor, or a Gas Torch fuelled by Liquefied Petroleum Gas (LPG)
Note: Keep the Brazing Hearth clean and dry and avoid using it for Soft Soldering : soft solder residues and splashes of lead/tin solder alloys can contaminate or adversely react with metal surfaces when heated sufficiently for Hard Soldering (this is especially true when working silver since the contamination could affect the assayable value of the finished product).
Features and Applications
Commercially available Brazing Hearths often have air compressors built-in to supply natural gas fuelled Blow Torches. Some also have a rotary table such that the workpiece can be turned as it is heated - this is particularly helpful when Annealing large items in Beaten Metalwork for example.
A perfectly serviceable Brazing area for use with an LPG fuelled Gas Torch can be assembled using Firebricks and other Refactory Materials such as Vermiculite. The materials can be assembled on a steel plate set within an angle section frame and mounted on a steel turntable bearing to create a rotary table if required.
Safety Point! Do note play a torch flame on to firebricks which have become wet : the resulting heat will turn the soaked in water into steam which may cause the bricks to explode!