Thursday, October 07, 2010

Rust bluing, start to finish *addition

with a new(old) formula.

Not long ago I found, while going through some papers, an old formula for browning steel. In the case of browning you’re rusting the piece appropriately and then brushing the rust off and oiling it to produce the finish, whereas with rust-bluing you rust the piece appropriately and then boil it(repeat as needed); but in both cases you need something to promote rust, so I decided to try this formula instead of the one I used to blue the Martini.

Test piece:
this is an old knife blank somebody gave me more years ago than I care to think about. It’s a plain 1095 carbon steel so it’s a good test piece. I started by taking it down to a nice bright 120-grit finish on the belt sander.

No, I did not take it all the way to 320, for the purpose of the test 120 will work just fine. And I’m lazy.

My old directions stated “Degrease, apply the solution with a cotton pad or cotton ball(I seem to remember a guy saying he grabbed whichever with a clothes pin, and just dumped the cotton after use), let sit a few hours. Apply a second coat, then leave until rusty.” So I got a cotton makeup pad(shut up, they have LOTS of uses) and wiped the stuff on, then about two hours later hit it again. Here’s how it looked the next day, not quite 24 hours later
Nice even coat of light rust, so I boiled it a few minutes, then wiped it down with steel wool to card off the loose stuff. Here’s how it looked after
With a bit of oil it’d have looked pretty good, but I’m giving it a second coat(as it were). Here’s how it looked 24 hours after the second treatment,
Very even coat of light rust. Here it is after boiling

This time I went ahead and oiled it to see just how it would look
Not bad at all.

I gave it a third pass: degrease, wipe with solution, after a couple of hours wipe again(no picture this time; how much rust you need to see?), leave overnight. Again got a nice, even coat of light rust. Boiled it a few minutes, wiped off under running water with steel wool, dried and oiled, and here's the result:
Gave a very nice, even color. Had I taken it to a 240 or 320 finish, would've been downright bright. Like regular hot-bluing, surface prep is a big factor in how nicely it comes out, although anything above 320 is a waste with this process(you can take it down to a mirror finish with hot-bluing).

That's the process; nothing mysterious, just takes some preparation and some time.

I think I may clean up that Martini receiver and see if I get better results with this mix.

Added: I have been reminded I forgot to say what the mix is.
The mix in question below my
DISCLAIMER!
This involves the use of acids. Get careless with them and you can get burns, you can damage your eyes, if you inhale acid fumes it can do nasty things to your lungs and other passages. If you decide to mix the stuff up, it's your own responsibility and use all precautions.
The solution is simple:
1 part nitric acid
1 part hydrochloric(muriatic) acid
12 parts water
Mix the above, put them in a container the solution won't eat/rust out/make brittle over time so it cracks and leaks.

3 comments:

Sigivald said...

Is the formula a secret, or do you wanna share with the rest of the class?

Firehand said...

Well, I remembered all the rest of it!

LibertyNews said...

And don't forget the old saying 'do as you outta, add the acid to the wattah'