OK here we go hope this explains what I did

first I cleaned the piece of metal tube then warmed it up with the wife's old hairdryer then sprayed a undercoat I then dried the undercoat off again with the hairdryer I then got the candle ect ready and sprayed the top white coat then while the paint was wet I lite the candle and held the flame close to the still wet paintwork and then dried it off with the hairdryer left it about a hour THEN let the grandkids have fun trying to rub the smoke effect off with a earser/rubber and NO they made no difference so job's a good un

Go on I KNOW you want to try it yourself.