Precision
Bluing offers hot-dip bluing only. The purpose of this process is protective,
decorative and restorative. This consists of a multi-stage process wherein the
piece is first derusted in either a solution of hot alkaline or an acid.
Determination is made by the severity and depth of the oxidation.
This is
followed by the mechanical removal of the etched surface by means of
multiple-grit felt and cotton wheels. Extreme care at this stage has to be
given to any lettering or proofmarks originally found on the piece. A veteran
polisher can work between the letters giving a quality overall effect.
Depending on the final grit used, this depicts the final finish, or luster.
Ex.
A 400 grit final polish is the approximate grit of a factory finish. To proceed
above a 400 grit, for example to a mirror polish would result in a very
reflective, high-luster blue. This is known as the custom and is only
achievable after many hours of hand polishing.
The
bluing process consists of a five-stage system: a hot degreaser followed by a
rinse, a mechanical scrubbing, then back to the degreaser, back to the rinse,
then into molten salts. These are classified as molten because the boiling
point is 290 degrees. After the appropriate amount of time, followed by a hot
water rinse, the part is placed in a spray rinse and sprayed with vast amounts
of water. It is then immediately quenched in a water-displacing oil.
At this
point, the oxide film is very soft and has to be left untouched for
approximately 24 hours. Then the oxide surface is mildly polished. It is then
possible to offer another service of a wax seal which gives an even higher
luster. The piece is then packaged and returned to the customer. This finish
also meets military specifications C13924BAM1 Class 1, Grade A.
A
very high level of attention to precision and quality should be given to each
piece for the best possible outcome.
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