There are 3 main elements to the movement finishing that I do. First, Côtes de Genève. Second, perlage. Third, bluing the screws. This entry will describe the process to blue the screws.
I took a digital soldering iron and made a custom tip out of copper with a couple of small holes drilled in it. I first made one out of brass but the soldering iron I have had a hard time heating up the brass enough to blue the screws…so that’s when I made the copper tip and it’s worked great. With the copper tip I usually set the temperature to 350 C, drop the screw in the hole and watch it turn blue, when it’s the shade I want, I pull it out w/ an old pair of tweezers and drop it into a small cup of water.
I bought a bag of screws off of eBay to practice with…and that made a big difference. Just being able to see how different the shades of blue can be. With all the practice screws I turned blue, it gave me a good feel for what color I wanted and how long it took. Most of the time the screws were on the iron for between 5-8 seconds.
Now concerning prepping the screws. All the screws are nickel plated…which won’t turn blue unless the nickel is removed. So far I have simply polished the nickel off the top of the screw…so only the polished face of the screw head turns blue. I like how they turn out w/ the slot for the screwdriver staying silver…
Anyhow, to remove the nickel, I simply sand each screw on 2000 grit sandpaper then on a 3 micron lapping paper and finish polishing with Mother's Mag and Aluminum polish on a micro-fiber cloth. After they have been polished, I clean them in an ultrasonic cleaner with watch cleaning solution…then they are ready to hit the soldering iron.
Many of the screws I practiced with weren’t plated…so when they hit the iron, the entire screw turned blue…which is cool too, but the only way to get that w/ the 6498 screws would be to take them to a plating company and have the nickel removed (which I may try one day…but for this project, I just went w/ removing the nickel from the screw face).