With soldering, finding the most suitable torch for your work can be difficult. Buying the wrong type potentially ruins work pieces and make them hideous or unusable. We look into common torches used by jewelers – from the traditional mouth-blow torch to modern varieties. In addition we included types of flame in heat-applied processes.
A blow torch is a device in which air or oxygen is mixed with a combustible gas, such as natural gas or propane. The mixture is burnt to provide heat for various jewelry processes. The combustible gas is obtained from the mains supply or from a cylinder canister. Air can be blown in from the mouth or pumped in by means of a bellows or compresser. If oxygen is used, this is usually obtained from a cylinder.
There are three types of blow torches: mouth blow torches, compressed air torches and bottle gas torches.
Mouth Blow Torches
No longer, or rarely, used by today’s jewelers, mouth blow torches are gas-air powered, with the user supplying the air through a mouth piece and hose connected to the torch. With gas board approved installation, this torch is connected to the mains gas supply or via a suitable pressure regulator to a bottle of gas.
Compressed Air Torches
Compressed air torches are used for large-scale work, or when a higher temperature is required. This type of torch burns gas at a fast rate. Of course, it is not possible to provide sufficient air by mouth, so a foot-operated bellows or an electrically driven compressor is used to force air into the torch.
Bottle Gas Torches
Torches of this kind operate directly from pressurized bottles of propane or butane gas and draw in their own air supply through holes in the burner nozzle. In compact bottle gas torches, the burner is fitted to the top of a small gas cylinder, which also acts as the handle of the tool. The cylinder may be either refillable or disposable.
We’ve now overviewed the main torch varieties you can consider. It is also important to consider what different flames apply to certain situations.
There are two main types of flame – a soft flame and hard flame.
A soft flame is blue and slightly wide with yellow tips. They suit most tasks, since much of the oxygen in the gas-air mixture of a soft or reducing flame is consumed. As a result, the metal engulfed by the flame is unlikely to oxidise.
Conversely, a flame is described as hard when it is bright and focused to a point. The metal heated by a hard or oxidizing flame will oxidise. Oxide forms in the presence of the oygen in the air surrounding the metal as the pin-point flame heats a small section of the metal.
Let us know what you discover—we love learning from your experience, too!