This could have been really cool if only you'd cropped just the hand and shot in brighter light to cut down on noise levels. I appreciate the obvious trouble you went to for the flames, though.
The lighting seems to be too even with everything at the same illumination. The background seems to be lit too much and probably would have been better with it more in the shadow so the fire could stand out more and be more dramatic. The right hand seems to be 'out of shot' and so could potentially be doing something to create the flames, but I have to admit that it looks a little photoshopped. The welding mask is a neat touch.