What's the final objective here? Are you thinking to flamecut
precious metal slabs the way you can flamecut large steel sculptures
with an oxy-lance?
(Sort of like chainsaw carving, only in steel, with fire. Cool to
watch (so to speak) but not exactly precise.)
If that really is where you're going, you should be aware that most
non-ferris metals have radically higher heat transfer rates, which
makes it much harder to get localized spots up over the melting
point without getting the whole billet pretty much molten too,
especially if you keep it up for any length of time.
So while what you're proposing isn't inherently suicidal, you're
likely to get molten metal all over the place, and unlikely to get a
result you'd want, at least if I understand what you're proposing
correctly. (I sort of hope I've misunderstood somewhere...)
Definitely need more before I can offer more than a "you
wanna do what???" sort of answer.