metal surfaces give better results. See the article on "Cleaning metal
Surfaces" for more information on cleaning.
We are assuming a clean, activated metal surface, preferably with a slight
'tooth' to it.
Cold fuming: Generally speaking exposure to a fume or atmosphere which attacks the
metal surface results in a more even effect except where condensation
causes pooling of moisture on the surface. A simple method for doing this
is to place the object on a small platform (to keep it out of the patination
agent) in a large plastic container or bag and pour the agent out on the
bottom of the container. It is then sealed and left to affect the metal.
Examples of this are ammonia and vinegar. See the page on "Fuming
metal surfaces" for more information.
Painted solutions: The solution is painted on with a brush or swab. It may be necessary to
use a tiny amount of soap or some alcohol in the solution to act as a
wetting agent in order to obtain an even surface. The metal is allowed
to dry and the application repeated a number of times until the color
development is satisfactory. Often this may be done outside to aid in
drying and eliminate fumes from the workshop.
Sprayed on: This serves as a method for obtaining an even or evenly speckled effect
on the surface. It works well for three dimensional objects. Again, repeated
applications and time yield the best results. Keep applications light.
If using a spray bottle the solutions may need filtering before use. In
the case of ammonia which decomposes rapidly in air one should spray the
surface and then seal it off from the air in a closed (plastic) container.
Bound materials: Where a material moistened with a patination agent comes in contact with
a surface etching, reaction takes place more readily at the point of contact.
An object can be wrapped in cloth or string to take advantage of this.
Organic materials such as feathers and plants may be bound to the object.
If tightly bound they will to some extent prevent surface activation
by the patination agent and their outlines will be visible on the finished
surfaces. When one binds with dry materials with or without organic materials
and exposes the surface to cold fuming they act as resists and use can
be made of this in developing pattern. In the case of ammonia it soon
permeates the binding medium and begins etching and reacting with the
surface at the contact points.
Pooling: If the agent is pooled on the surface it reacts where it is pooled. Fingerprints
can be used as a grease source to force pooling to occur. Pooling will
result in a variegated effect as the edges of the puddles will act differently
upon the metal than the centers.
Immersion: The object is immersed in the solution. This tends not to work quite as
fast with the agents recommended here but can produce even finishes. In
some cases (as ammonia on brass) strong etching of the surface can take
place. Immersion can be used as a method of coating an object with a solution
by dipping it, removing it and allowing it to dry. This can tend to produce
a concentration of effects where the liquid has run down the piece while
Moistened shavings Moistened (not wet) wood shavings or other porous materials work very
well for differential patination/etching of surfaces. Again, contact points
are the focus of action on the metal and very interesting surfaces are
possible. Using ammonia or vinegar etching takes place producing texture
as well. Possible media for this include resin-free sawdust and shavings,
peanut shells, kitty litter, Styrofoam balls or chunks, crushed cork,
sisal or other coarse fibers, pine needles, grass clippings, organic materials
such as leaves, feathers and so on. Use them in a sealed plastic container
to prevent evaporation. The piece may be shaken up in them to obtain an
even effect. Rowe and Hughes suggest making a dam of modeling clay to
contain the most media in order to obtain pattern development or block
areas of such effects on a piece. It should be noted in this context that
modeling clay has a high sulfur content and will attack and etch silver
while turning copper alloy surfaces black where it contacts them. This
too could be used in developing pattern. The cat box or hamster cage could
provide a good medium for patination in this technique.
Paste applications Patination solutions can be applied as a paste, in fact the plasticine
just mentioned could be a paste application which results in a patterned
application. The patination agent is mixed with a thick carrier (such
as clay powder etc) and applied as a sticky patch with attacks the metal
Some agents recommended for use on copper alloys
Household Clear Ammonia: fume produces greens and blues, olive green
on bronze. Can produce bright blues with brass especially when used as
a fuming agent. It affects the structure of brass if left in contact too
long (possibly reacting with the zinc) and the brass may crumble or fall
to pieces with light pressure. Therefore if using brass and ammonia the
structural elements of the piece should be in copper or another metal.
Vinegar: fume produces dark greens,
blues and will also affect brasses in the same way as ammonia.
Salt solution: Varying strengths
of salt solution may be made up and applied to the metal. Colors formed
include some tones of red on copper. Deep green is common.
Dry salt: This can be sprinkled on
the metal surface. It draws moisture to itself in a humid atmosphere and
will react with the surface over a period of weeks. When finished the
loose material may be brushed off leaving a variegated surface of greens,
browns and possible reddish patches.
Iron filings: In combination with
any of the above they will react to produce localized dark mottled surfaces.
Combinations: Various combinations
of the foregoing are effective for patination. There are also other household
chemicals which will produce patinas on metal.Try other things as well, borax, baking soda, are examples. Just think
about what you are doing because you can get into trouble mixing chemicals
without considering how they react with each other. If you were to mix
bleach and ammonia for instance you can produce chlorine gas and kill
yourself - there are deaths every year from people cleaning homes overcome
by this combination.