The baking lacquer I got at Brownell's is tougher than hell. I'm of the opinion that it never changed color in the 20+ years I've been using it. The gun has been used, hard, in that space of time, and there is no sign of chipping, peeling, scratches, or, whatever. I'd speculate that it compares favorably with automotive grade clear coat, for toughness, and resistance to color change or fading.
Dr. Sane, Thanks for noticing. Being a 1946 vintage gun, that Darne was among the first to have cyanide colors applied as a post war gun. Previous Darne guns were the more typical bone pack, and, of course, have a different "look" to them. The bone color guns, pre-war, also had a quick coat of varnish or lacquer applied at the factory, a step that was done away with on cyanide color guns. I find both varieties pleasant to look at, and I'm a fan of the finish called "coin", as well, if it is done right. I feel the Browning BSS sidelock guns just look right with the coin finish that was used, although I have no idea what that was. Nitride perhaps?
The later Darnes with the silver finish, often called "French Gray Hardening" use a process very similar to color case hardening, except the final quench occurs in a solution of potassium prusiate, instead of water. The silver color can be altered in tone somewhat by playing with the chemistry of the quench. The color is no more or less durable than color case hardening.
The Darne company quit cyanide hardening guns when they made the switch to high carbon tool steel forgings to build their guns. It doesn't color well.
Best,
Ted
