Originally Posted by Tootsall

Let me just whip this out! (pulling tape measure out of desk drawer).... and measuring up a trumpet. (darn hair keeps getting in the way)

I calculate approximately 211 square inches of surface area on a standards Bb trumpet INCLUDING the inside of the bell down to where it joins onto the bell tube (about 2.5" from the bell rim). If the gold is layered on at 4 micron (four millionths of a meter) then there is roughly 0.033 cubic inches or 0.54 cubic centimeters of gold. At a density of 19.3 gram per cc that works out to 0.36 ounces. With a selling price of $460/ounce you are looking at $160 worth of raw gold not including silver undercoat, many hours of cleaning/plating, "infrastructure" (plating tank, ventillation equipment, solutions, etc.)

You can work the numbers out for yourself if you wish... treat the first 2.5" of bell as a "frustrum of a cone".

Is anyone really "making a killing" at gold plating? Not likely!