Boarded Chest II
2014.08.08
I decided to build another boarded chest. The first step (after buying more strap hinges from Lee Valley) was to make the hinges darker. The chest will be painted with yellow milk paint and I want the hinges and nailheads to stand out. The simplest method would be to paint them black; but this does not look even remotely authentic. You can also buy hinges and other hardware with “black oxide” powder coating, which is equally dubious; you’ve seen these as gate hinges everywhere. The best method would be to buy actual wrought iron hardware, but since this involves hand forging by a skilled blacksmith it is expensive. Buying antique hardware would be another approach.
Although rust is inevitable given time, moisture, and oxygen, various protective coatings will resist this process of decay. One technique is to create a thin layer of black oxide on the steel or iron. This mineral is magnetite, and is a fairly stable form of iron oxide, as opposed to the unstable and corrosive red iron oxide rust. From an aesthetic standpoint, it looks more time-worn than bright steel.
Bluing is a subset of black oxide, often used on firearms. The industrial process is usually a hot alkali salt solution. For touch-ups where the original bluing has worn away, various companies sell small bottles and tubes of chemical cocktails which can be applied “cold”, e.g. at room temperature. This particular product contains selenous acid, nitric acid, and cupric sulfate. I set up a work area outside and wore protective gloves.
The hinges come with some mill scale and a little rust in the pits. I cleaned all of that away, scrubbed with steel wool, and removed any oil or grease with rubbing alcohol and other solvents. The steel should be as clean as possible before applying the bluing, although I want a more varied appearance than the average gunowner would.
I squeezed out some of the bluing compound and rubbed it around with a cotton ball. The reaction is almost instantaneous, though over-pronounced while the paste is still on the steel.
The instructions said to let it sit for 30 to 60 seconds, then wipe away under running cold water. Then I lightly scrubbed with steel wool, and went through the de-greasing process again.
After that, it was back outside for a second coat, rinse and clean, then the same process a third time. Three coats seems to be about the usual limit; after that, the steel does not become noticeably darker.
2014.08.09
Then I applied the gun bluing to the nailheads, using a q-tip. The hinges look almost flat black in the photo above, but here you can see that they’re really a mottled dark gray.
