I Parkerized my 1927 Colt last night. I began the refinish process by glass bead blasting the entire gun, except for the barrel, bushing, disconnector and sear. Only the feed ramp was taped off. I used a pint of Duracoat Zinc Phosphate Parkerizing Solution from Lauer Custom Weaponry. I mixed 4 pints of distilled water with (1) pint of parkerizing solution. I mixed and heated the solution in an enameled pot on a hot plate.
The instructions say to heat the solution to 170°-185°, but I had a lot of trouble getting the solution up to 175° because the bottom of the pot wasn't flat and didn't conduct heat very well. I finally got the solution up to 170° and added the requisite course steel wool pad and allowed the solution to cook for 30 minutes.
When I put the parts in, I didn't get much of a chemical reaction as one would expect, most likely because the temperature was hovering around 175°F and I couldn't get it any hotter. After 30 minutes in the solution, I pulled the parts, threw them in a bucket of hot water and used a toothbrush to knock all the 'frost' off the parts. The parts were a light gray, but the finish was very thin and light. Interestingly, the Hammer and the Magazine Release came out a dark gray, almost black.
I then fired up the gas camp stove and brought the solution up to a light boil, removed the first steel wool pad and added a second one. I then dropped the temperature to 185°-190° and re-introduced the parts into the solution. I still didn't see the 'gassing' that one would expect, although some parts did 'gas' more than others. Every 5 minutes or so, I would removed the 'gassed' steel wool pad and throw in a fresh one. All in all, I used (6) steel wool pads in the solution and I added (1) additional pint of distilled water to replenish what I lost from evaporation. I began to believe that perhaps my solution was bad, so I just turned the fire out and let the solution start cooling. The parts spent about 30 to 40 minutes in the solution all total, most of that time around 170°F.
I pulled the parts and submerged them in a bucket of hot, soapy water, scrubbed the briskly with a toothbrush and dried them with Brake Cleaner. I then placed several large sheets of foil on the camp stove and warmed up the parts with indirect heat. Once the pieces were too hot to hold on to, I began spraying them with Break Free. Instantly, the parts began to smoke and I turned them with rubber covered tongs and continued to apply more Break Free until they were saturated. At one point, the Break Free ignited and I just let it burn itself out.
I tuned the heat off and allowed the parts to cool and then I wiped them with an old silicone polish cloth. The result is a grayish-green, very uniform color that I think looks great. The only 'blemishes' are where the slide is heat treated near the slide lock notch. In this area, the Parkerizing didn't color quite as well.
I thought you might find this interesting, so I have attached some photos of the restoration process. The last two photos show the 1927 Colt with its fleet of Tripp Magazines and a side-by-side colour comparison with my factory-finished Norinco 1911A1.
I hope you find this informative and helpful....Robert