Barrels with Gold inlay, that thought can still bring back memories I would sooner not remember. To be honest I have only Browned/Blued a hand full of barrel sets but my first was nearly my last. It was many years in the past now when I first started re finishing guns though later on I found that I was more comfortable with the wooden part of a gun. After applying my usual rust browning/Bluing solution gleaned from Angier's the Gold inlay changed its coat to Silver because of the Mercuric Chloride in the solution... Disaster I thought! Well the Gold did return to normal after some Tooth Paste on a cotton swab, though the gold went back to silver on the next coating of solution. The only thing I could do is to spend a lot of time in the local Library's reference section trawling through through books on G unmaking for an answer. The answer came leaping of the page of a small book written some time in the Early 1900's
It was the practice in his Birmingham workshop to Brown/Blue barrels using the "Hot Box" method and not putting any rusting solution on the barrels at all, he had my full attention. What he described was a wooden box that had the capacity to hold 5 barrel set hung from a rail at the ts at the top, at the bottom of the box was a low wattage electrical heater and a dish of dilute Hydrochloric Acid. The method was simple polish up the barrels keeping away from the gold and the de grease well in fact the recommendation was to ware cotton gloves to keep hands away from the barrel metal. Plug up the bores using rubber bungs hang the barrels in the hot box having firstly wiped them with a goodly amount of distilled water to get things going and do not forget the gloves , rust should start to appear after 12 hours then card with de oiled wire wool. My box was smaller just to hold one barrel set my heater was a 15 Watt bulb the Hydrochloric Acid was the used for brick cleaning about 60% Acid. Continue rusting until you obtain the desired brown or if blue is required boil the barrels i distilled or rain water.
It worked well no rusting solution wiped on the barrels only a rusting vapor with the big plus the Gold was the same after as before though I will say it is slower method of Browning/Bluing though it works well when you become more efficient at it .
