I want to mention a little quirk the 3A has along with many other torches. Occasionally it may backfire so you probably want to use a fuel gas flashback arrestor inline with it for safety reasons. Even then it may backfire and start to burn inside of the torch. When it is doing this it will make a strange whistling sound. Turn the fuel off to put the internal fire out. Then start over. If left burning it could actually melt the torch.
In the link below we have Gianni Toso, an italian master working with a 3A so watch it in action.
He is using a Multi Hole tip with oxy propane.
https://www.youtube.com/watch?v=FYEQ...dulY8T_Rto37sg