MARK LEE METAL FINISHING FORMULAs
HOW WINCHESTER RUST BLUED
Winchester used rust bluing mainly on their barrels. Their process used a slow rust solution very similar to Mark Lee Slow Rust #3. Winchester used an accelerated rusting process.
The following instructions are the original Winchester shop floor instructions used for rust bluing Winchester Model 21 double barrels. You'll notice how much effort went into the cleaning of the parts and how short of a time the barrels were left in the rusting chamber. Also notice that the barrels went through a dry heat operation to keep the parts free from condensation when they were put in the high temperature humid environment.
Winchester Shop Floor Instructions for Model 21 Barrels.
Degreasing was done in a Vytelene solution to remove oil and grease. Next, they cleaned the parts in a boiling Dulite #29 strong alkali solution for 30 minutes, followed by a dip in cold water to remove the cleaner, then washed in boiling water for 15 minutes. The barrels were cooled to room temperature to avoid uneven reaction of the acids in the next operation. Bluing solution was applied with a piece of natural sea sponge. Metal parts were left to dry at room temperature for a minimum of 6 hours but preferably left overnight. The second coating with solution then dried at room temperature for approximately 15 minutes. The barrels were dried in an oven for 15 minutes at a temperature of 180-225 F to bake the acid dry and preheat parts for the rusting operation. The warm barrels were then placed in a humidity cabinet for 7 to 15 minutes at 150 F and 75% to 95% relative humidity to form a coating of rust. The barrels were placed in boiling water for 15 minutes to change the brown rust to black rust. Parts were then dried with an air hose. Using a soft wire wheel, barrels were carded to remove excess rust and unify the surface. The cycle was repeated 4 to 5 times. During the whole operation there was no touching of the product by the hands and no oiling or greasing. The sponging operation used a natural sea sponge and the sponge was rinsed in water immediately after using to keep it from disintegrating. Rubber gloves were used for sponging and barrels were handled by using two wooden dowels.
The testing product was rubbed with a pad of #0 steel wool and an applied weight of 11 pounds. The pad was run 6000 cycles, producing 12,000 strokes. The approximate time was 100 minutes.
The end result was a blued surface free from bare metal, although a change of color was expected.