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Rust finish & patinas


#1

can anyone tell me how to achieve an even rust finish on mild steel?
i am making marriage of metal with assorted metals and mild steel,
and would be so happy to “patina” the mild steel with rust, but so
far have only gotten splotches of the rust.

also, i am interested in making rokosho, from the homemade recipe in
tim McCreight’s book. can anyone give me advice on a supplier for
such chemicals? or even a supplier for the traditional japanese
rokosho solution?

i would so appreciate any advice! thanks…
joanna gollberg


#2

Joanna: Have you tried a mild acid like muriatic available at
building supply outlets. I would use it with very good ventilation
and proper protection for using acid, but it should rust steel.

Ken Gastineau


#3

Joanna, One method that has worked well for me on steel is to use a
spray bottle with vinegar for a nice even application. Each type of
vinegar (white, wine, rice, balsamic, etc.) produces a slightly
different patina color and texture. I would recommend that you test
each of them on a labelled scrap to see what works for you. It
should take you up to 3 days for the first layer of patina to fully
develop – after that, successive applications of the vinegar (using
a sponge or sprayer) will deepen the patina much more quickly. Allow
to air dry between applications of vinegar.

Keep in mind, too, that the steel’s surface needs to be "roughed up"
in a best case scenario – steel wool or sandpaper are best. And it
must be clean before starting – clean it well with denatured alcohol
before your first spraying to avoid unevenness.

Good luck!
Karen Goeller
@Karen_Goeller


#4

Joanna -

One way to get a good even patina (i.e., rust) on steel is to
combine water and salt in a sprayer and evenly mist the whole thing.
Use a fine mist to get an even coating. Then let it rust. Probably
will need several coatings. And it helps if you heat the object
before spraying.

Ivy


#5

Hello Joanna; You can sometimes find a compound called “Plum Brown
Barrel Finish” in stores that carry supplies for gun care. It’s a
finish popular on some shotgun barrels. Be VERY careful handling
this stuff as it contains mercury compounds. Your alternative would
be as follows;

  1. obtain some ferric chloride from Radio Shack or other electronics
    supply stores. Dilute some of this with water to about 1 parts
    Ferric Chloride to 9 parts water. This can etch many other metals,
    so you’ll need to mask off everything but the steel or iron with
    something like asphaltum or nail polish.

  2. Degrease the metal with soap and water, rinse, dry, and spray it
    down lightly.

  3. Wait and watch. When you’ve got rust started, rinse and spray
    with the Ferric Chloride again.

  4. When you’ve got the degree of rust you like, neutralize the
    Ferric Chloride with Ammonia and rinse clean with water.

  5. Coat with a protective material like “Renaissance Wax” or
    Johnson’s Original Formula Paste Wax.

David L. Huffman


#6

Good answer Ivy, What you have [at least partially] described is a
process called “browning” and was used in the firearms industry prior
to the use of a more chemically stable process called “bluing” (of
which I am sure you have heard). The addition of an oven to heat the
metal (once coated with the brine solution) completes the process
description. Unfortunately, I can’t recall the time/temperature
schedule of the heating.

Tom


#7

Do NOT get ammonia and hydrocholric which is muratic acid together,
you will release chlorine gas. I use ammonia all the time for
cleaning, but got away from the muratic due to fumes…Muratic is a
great de investment tool, but fumes are tough and require
care…That would also be my solution for rust.
LET US KNOW HOW IT DOES>>>> Jay Cardwell


#8
    Do NOT get ammonia and hydrocholric which is muratic acid
together, you will release chlorine gas. 

G’day; Sorry; not true. Mix strong hydrochloric acid (HCl) with
ammonia (NH40H) and it will get very got indeed and will probably
boil explosively with the emission of dense white fumes of ammonium
chloride (NH4Cl); NOT chlorine gas. Ammonium chloride is fairly
harmless, but don’t breathe more than you can help. Just bringing
stoppered bottles of strong ammonia and hydrochloric acid together
will produce the white fumes. – Cheers for now,

John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#9
      Do NOT get ammonia and hydrocholric which is muratic acid
together, you will release chlorine gas. 

As John B, already noted, this isn’t true. Perhaps what you’re
thinking of is that you should never mix ammonia with Chlorine
bleach. this is more commonly possible than mixing the ammonia with
acid, since most households don’t have acid, but most have both
bleach and ammonia containing cleaners, and both products are used in
cleaning. Mixing bleach with ammonia CAN release chlorine gas.

Peter


#10

Hello Joanna

In the old days a browning of steel was achieved by putting the
steel object in pigs urine. Take it out daily and rub it with a steel
wool. repeat this until a very tough brown oxide layer is formed.

But I can imagine you like to do it easier. I have some formula’s to
do it faster. but they all contain HgCl2. Sublimate. and this is no
nice stuff. But I have also one without the sublimate.

all in weight parts

70  parts  HNO3
140 parts alcohol
280 parts Copper sulphate
10 parts  iron (as filing powder)
1000 parts water

heating of the fluid will speed up the process.

greetings

Martin Niemeijer


#11

Mixing acid and ammonia is not a good idea as John states but the
thing to really NOT mix with ammonia is laundry bleach . This does
liberate Chlorine gas. This is very rough on the lungs but
fortunately it is so irritating that you should pick up on the
problem immediately it is not subtile.

Jesse