Air-acetylene produces a flame temperature of around 4000° F (2200° C). This is hot enough to solder aluminum work glass, repair radiators and braze plumbing fixtures. It is not hot enough to weld steel. When acetylene is burned in pure oxygen, the flame temperature may be as high as 5730° F (3166° C).
The oxyacetylene process produces a high temperature flame over 3,000 degrees C, by combustion of pure oxygen and acetylene.