Mixed karat gold piece

I am not a jeweler, I am a flute maker. But I am seeking your
collective wisdom & experience regarding a flute that I want to
make. The tube will be high karat gold-possibly as high as 20K. The
keys and other parts need to be 14K. My customers are not jewelry
customers, they are musicians. Still, there are ethical obligations
as to the way the flute will be stamped, as well as legal ones,
possibly. After having searched the FTC web site thoroughly, I still
have no answer as to how a substantial work in gold (such as a
flute) has to be stamped to show components of differing karats. Can
anyone here advise me or point me toward a good source for the
regarding this?

Incidentally, an all-14K flute weighs about 16 ozt. Steels, pads,
adjustments and headjoint cork account for about one ounce. The rest
is 14K gold.

Thank you, EW

gold-possibly as high as 20K. The keys and other parts need to be

Elizabeth, this question has come up before - not flutes, but mixed

And I’ll assume you are in America because you didn’t say otherwise.
I’m not sure I’d make a flute out of any standard gold alloy higher
than 18kt because of durability - there are some more exotic
alloys… But that’s another issue…

The key is solder… If the pieces are soldered together then you can
stamp the main piece - I believe it was established that it’s not
necessarily the letter of the law, but it’s a fact that it’s common
practice. On your flute you cannot legally stamp the body of the
flute both 20kt and 14kt.

because the keys are separate parts. You are supposed to stamp each
key separately, though you don’t have to stamp anything at all. You
can sell gold rings all day long without stamps, you just can’t call
them gold - again, by the letter of the law…