I for onelove that deep, high polish blue. With the exception of my milsurps, I want a finish that looks like black/blue glass.
I have done entire guns with cold blue; I still have my first rifle, a sporterized '03 Springfield that I cold-blued. Still has the finish on it, and it still looks good--and I blued it close to 20 years ago.
Here are some tips for polishing:
1. Learn the proper wheels to use for the proper results. There are three basic types: the felt wheel (hard or soft), the loose muslin wheel and the sisal wheel.
The sisal wheel is for rapid rust and flaw removal. This wheel can be BAD JUJU--with polish on, it WILL cut metal fast!
The hard and soft felt wheels are used for a mirror finish. However, they can also round out screw holes and remove factory marks if used with the improper polish.
The muslin wheels are good all around wheels. When used properly, you can use them all the way from start to finish.
There are some guidelines, though.
First, make sure that you have the proper motor for the job. A good bench motor, developing at least 1/3 hp is a must.
6 inch wheels are good, but the work area is greatly reduced. You can also double up on the muslin wheels to polish a greater area.
After mounting the wheels, get and use a good wheel rake to true and even the wheels prior to use.
I use and recommend the Brownell's Polish-O-Ray series. It is specially formulated to polish gun steel, and it does a great job, too. Here are the polish grits I use:
If I just polishing to blue without flaw removal, I'll use 400 grit, then go through 555 black, gray, and finish with white. If I have done work or flaw removal, I'll start with 220 grit, then to the 400.
Start your wheel first, then load it with polish. Use a light pressure, let the wheel take the polish slowly or else you'll be flinging great chunks of the stuff all over your shop area. Also, don't wear your best clothing when polishing; I recommend a good shop apron.
Use a separate wheel for each grade of polish, and put your wheels in plastic bags between jobs. Keeps them from picking up dust and dirt and other garbage, too.
Finally, when you do polish, use only LIGHT pressure. Just hold the work against the wheel; let the motor and the wheel to the work for you.
For cold blues, I like the Birchwood Casey Perma Blue paste. I prep the metal by first polishing, then wiping with denatured alcohol. Do NOT touch the metal with your bare hands after the alcohol, it will affect the bluing. Also, after the alcohol evaporates, rust will start almost immediately. Blue immediately.
Use a propane torch with a spreader tip and a low flame. Carefully heat the part to be blued; not too hot, you're looking to warm the surface only. After this, apply the Perma Blue. Be generous with it, too! I have found that a big piece of felt is ideal for applying the bluing.
After the paste is applied, let it sit for about 1 minute. Now, polish with a crumpled up brown paper shopping bag (No, I'm NOT joking!)
Apply about four coats, polishing with the bag between coats.
When you're finished with the fourth coat, hand buff with 0000 steel wool. You'll LOVE the depth of the finish!
IMPORTANT!!! Immediately apply a good light oil, such as 3-in-1 liberally. Let it sit for about 30 minutes, then wipe off the excess.
Now comes the hard part:
DO NOT TOUCH OR HANDLE THE GUN PARTS FOR AT LEAST 72 HOURS AFTER BLUING. This gives the bluing a chance to mature.
Finally, re-oil and assemble, and the job's done.