A temporary hearth was assembled on my picnic table to enable the experiments to proceed. A 4inch nail was to be heated up. I connected the propane and set it at 0.7bar, and the air at 2bar. I switched on the gas, and started the compressor, lit the gas and turned to full, turned the air on very slowly, and was amazed and surprised at the power of the jet. The nail heated up to bright red in a matter of seconds. What a difference that compressed air makes. As to the jet size, diameter of flame tube and gas and air pressure settings they were perfect. I really cannot believe what I achieved it has given me a real boost.
Thank you Ironman for your help.
Cheers David