Some Patina Notes

Whaaat? Yeah, patina. I've been making some steel stair rails for my condo. Picture to the left here. Long story. But today I'm getting warmer on the finish.

I decided not to paint them. So I'm using a patina. Best I can tell this solution is a mild acid with something in it that oxidizes the iron a bit. But not so much that it strips the oxide off. I got a process to work pretty well so I'm recording it here.

The patina is sold by Sculpt Nouveua. http://www.sculptnouveau.com/ It's made by Birchwod Casey and goes by the name PC-9 Presto Black (Aka: Gun Bluing)

http://www.birchwoodcasey.com/metal/iron.html

I also got some red dye to give a red tint to blend with my tera cota quarry tile.

The directions are kinda sketchy. So I had to experiment a lot. So far here's the process.

1.) Sand the metal, a lot. I belt sanded the top of the rail and then gave everything else a good once over. The lower bar can't really be seen up close, so it needed to be clean, but not as good looking as the top. Make sure you wear a good dust mask (3M n98) and hearing protection if you are belt sanding.

2.) De-grease with lacquer thinner or acetone. Don't use paint thinner. Paint thinner has oils in it that stay behind. De-greasing requires a bulk wipe down to get all the crap off, and then a second wipe down to get it really clean. Sometimes a third round is needed. The final should be done with paper towels or really clean cotton rags. White only. You don't want any dyes getting on the metal.

If you don't de grease you get the finish picured which is called "birdseye". It's the result of the lacquer not sticking to the oil deposits on the surface of the metal. Also, the patina doesn't go one as easily and you end up using more of it. It's not cheap.

3.) Light acid wash with a 10% or so solution of HcL (33% HcL Pool Acid cut by 1/3 rd.)

4.) Apply the patina solution using a Scotch Brite pad. This was tricky. I started by getting some on the pad and then getting the entire surface damp. Then I put more on the pad and went pack over it. The more you go over it the darker it gets. Don't press too hard or you strip off the oxide layer that you want to leave behind.

There's a fine line here. The Scotch pad aids in agitating the patina to get it to react with the metal, but the harder you work it the less oxide is left behind. The trick appears to be to use as little down force as you can and keep the pad moving all along the rail.

5.) Wipe it down with a dry rag and dry wipe or "burnish" the residue off with a dry rag. Use lots of rags along the process. Dirty rags just leave residue behind.

6.) Repear until it's dark enough. My second rail is lighter than the first one. I might re-do it. Not sure. I'm not sure anyone will really notice.

7.) I applied some red dye in a clear lacquer with a sponge that was wet with lacquer thinner. Again the trick was to wipe the entire rail in one continuos movement. I actuall did one side and then the other. It is streaky, but that's the effect I was looking for. If you want it even, an air brush would be required.

8.) Spray it with clear lacquer.