Harris 19-6 Propane FAQs
Answers to common questions about the mixers, cutting attachments and nozzles used when a hand torch is run on propane with oxygen.
How does oxy-propane differ from oxy-acetylene?
Acetylene burns hotter than propane in oxygen, with figures of about 3100 degrees C against about 2800 degrees C commonly quoted. Propane still gives plenty of heat overall, but most of it sits in the outer part of the flame rather than the inner cone, so it needs a different technique. Propane also needs far more oxygen for the same flame.
Because of this, propane is common for heating, preheating and general cutting, while acetylene is quicker at preheating and piercing. The right choice depends on the job and the equipment you have.
Can I use propane for welding steel?
Propane does not give the same results as acetylene for welding steel. Oxy-acetylene is described as the gas combination with enough heat to weld steel, whereas propane, hydrogen and coal gas are used for joining lower melting point non-ferrous metals.
Propane is better suited to brazing, silver soldering, heating and cutting. If your work is fusion welding of steel with a gas flame, acetylene is the usual fuel. Check with the maker of your torch before using it with a different fuel.
Is propane suitable for brazing and silver soldering?
Yes. Propane is used for brazing and silver soldering, as well as for general heating. Propane has a lower flame temperature than acetylene, so larger or thicker parts may take longer to bring up to brazing temperature.
Use a brazing nozzle or heating tip marked by the maker for propane, and set the flame as the filler maker advises. Heat the parts being joined so that the filler flows into the joint by capillary action, rather than melting the filler directly in the flame.
How do I choose a propane cutting nozzle size?
Cutting nozzles are chosen so that the diameter of the cutting oxygen hole suits the thickness of the material. Use a nozzle made for propane, as acetylene nozzles are designed for a different flame. The maker supplies a chart of nozzle size against thickness and the oxygen and fuel pressures to set.
Too little cutting oxygen gives poor slag removal, and too much gives a rough finish, so set pressures from the chart rather than by guesswork. If the material is thick or unusual, ask the maker or our team.