Ticm, I believe you are confusing issues. If a person is using a tone-ID machine, where he's elected to hear everything (and simply use his ears to decide what to dig, verses what to pass), that's not the same as going "all-metal". What I'm trying to say is, the very moment we md'rs use disc. mode TID, EVEN THOUGH WE MAY HAVE OUR SCREENS "WIDE OPEN", is still a form of discrimination, because we are still using our ears to pass iron, or foil, whatever else we elect to. If you want to know what real "all-metal" mode is, you'd have to go to a machines pinpoint mode (or all-metal mode, or whatever each particular machine calls it), and listen in that mode. Everything will sound the same, with no TID. Only THAT is true all-metal. The other is still a form of discriminate (albeit with your ears).
ok Jimzz977, to answer your question: no, you will not loose gold, if you knock out iron. Because gold is a higher conductor than iron. But this is a trick question though! Because if you're talking extremely small gold items (ie.: pinhead nuggets, or dainty thin chains, etc...), they can read ssseeeoooo low on the TID scale, that they are dangerously close to the iron range. And the reality is, most machines ........ once you knock out iron, might include the range of wet-salt conductivness, and could over-lap into the extremely low ranges of teensy dainty targets.
But assuming you were talking about normal regular gold jewelry items, no. You can knock out iron, and find gold all day long. You're just going to have to allow foil and aluminum in though, as gold (especially smaller items) can read down to small foil. Bigger gold (ie.: fat men's bands, etc...) read up to tabs and so forth.
