JC week 7 how to : DIY antique brass patinas, ammonia, sulphur and vinegar.

NB: journal entry for the Jewellery and Small object module at South bank Griffith university (QCA) to view the full journal click here

How to patina brass using Hot and Cold techniques

ABOVE LEFT: cold patina created with sulphur (eggs)
ABOVE CENTER: hot patina created with brown vinegar
ABOVE RIGHT: cold patina created with ammonia
ABOVE BOTTOM: non-patina brass

This post contains directions on how to patina brass using eggs or ammonia or brown vinegar and a heat gun to create the results as pictured above. For my project I am needed to age the brass for conceptual relevance and am choosing to use the egg patina ( its not as pretty but looks more aged).


A few quick notes about the petinas:
The hot method is faster, Most hot patinas are transparent. The benefits to using heat,   is that the patina chemicals get sucked up by the metal – it’s more than a surface-only treatment. 
Cold Patinas are, as a general rule, opaque.  The application of these patinas involves applying the agent  onto room temperature (cold). The drawback to cold patinas is that they are relatively fragile and need to be protected – either structurally or with lacquers, varnishes or waxes. 

WARNING

Before begining to patina your metal, make sure that it is clean and free of finger prints as these marks will effect the finish.

PATINA  type one cold patina: BOILED EGGS ( When Liver of sulphur isnt available) 
the idea here is that the eggs give off sulfuric gas, which is responsible for giving the brass a patina finish.

Place an egg into a saucepan and boil on high for 5 minutes 

Remove the egg from the hot water using a slotted spoon and rinse it thoroughly under cold running water. Keep it there until it feels cool enough to handle, but not yet ice cold. Chilling the egg makes it easier to handle, and chilling the egg quickly helps separate the shell from the cooked egg white.

 Roll the egg gently on a flat surface to crack the shell. Then, use your fingers to peel away the rest of the shell.

Use a kitchen knife to cut the egg in half lengthwise. Note that both the egg white and egg yolk should be cut in two

Place both halves of your boiled egg into a resealable plastic bag, along with your brass piece. Seal the bag well

Sit the bag in sunlight for several hours. After several hours pass you should notice a subtle patina forming on the brass

The results of the egg patina

PATINA type two cold patina : ammonia
The ammonia will produce a very dark green and blue patina on brass metals

You will need an air tight jar, ammonia, table salt, paper towel and protective glasses and gloves for this project

Line a deep container with paper towels. Crumple up a few clean paper towels and place them inside a container with a lid.

 Pour ammonia over the paper towels in your container, adding enough to saturate the paper towels.Ammonia is a hazardous chemical, so you should only do this in an area that is well-ventilated.

Sprinkle salt on top. Pour a generous amount of table salt over the paper towels in your container, distributing it evenly over the surface.

Place the brass inside. Rest your brass piece directly on top of the coated and soaked paper towels. Press gently so that the bottom and sides of the brass come into direct contact with the ammonia and salt.

Cover the brass with additional ammonia-soaked paper towels. Crumple another clean paper towel and place it directly on top of your brass piece. Pour more ammonia onto the paper towel, soaking it thoroughly.

Place the lid on the container. Secure the lid in place and set the container aside for a few hours. For this experiment it was left overnight ( starting at 1pm to 6am )

Once you notice blue forming on the paper towel, that is the indicator that the patina is working.

This is the results of the brass and ammonia patina overnight test

PATINA TYPE three HOT patina: brown vinegar
This method of patina produces a rainbow/brown patina finish. This patina is the fastest of the three to complete but requires the metal to be heater to approx 200'c or higher

WHAT YOU NEED : Heat gun, a surface to heat the metal on ( ceramic tile, frying pan and steel container ), brown vinegar

 Step 1: Heat the brass plate , I heated the plate for 5 minutes with the heatgun set to 650'c.
Step 2: pour a small amount of brown vinegar directly onto the hot brass plate
Step 3: reheat the brass plate till all of the vinegar has evaporated. again this was for 5 minutes with the heatgun set to 650'c

Result of the brown vinegar HOT patina test
The effect is similar to oil or holographic paper, the coloration changes depending on how the light hits the surface.

Research
http://www.beadinggem.com/2014/01/gun-blue-vs-liver-of-sulfur-patination.html
http://www.nancylthamilton.com/techniques/patinas/
http://www.wikihow.com/Patina-Brass
http://www.howtoantiquebrass.com/how-to-antique-brass-with-vinegar/