From 1936, and bantam #72

Competing gangs of crooks are battling for the secret of the Metal
Master -- the ability to melt any metal instantly, without heat. this
involves chasing back and forth around New york city, and a trip to
Alligator island off the south Carolina coast. there's a substantial
amount of capture and release that goes on and

S
P
O
I
L
E
R

A
L
E
R
T

a rare thing in that we see one of the guys go undercover for
virtually the entire book. also noteworthy for some of the most
annoying Dent character dialogue ever with the sex captain from
Sphongebob Squarepants as assisytant villian, and Punning Parker as
well.

The gimmick ends up being ridiculous, and the explanation at the end
still can't explain how the metal melting gimmick was able to be used
several times in the book. but the narrative keeps going, and there's
no real letdown anywhere.

I'd maybe nominate THE METAL MASTER in the category of "Most Average
DOC SAVAGE Adventure"