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Fakenham, England, NR21 7AE
United Kingdom

07549051224

Subtle Green with White and Iron pattern

Patination

Subtle Green with White and Iron pattern

wayne mckinney

 
classical green patina.JPG

'Serenity' by Annie Tempest

 

Subtle Green Bronze Patination

 

Description

A foundry favorite and an absolutely beautiful patina for a smooth surface. It's a very complex patina to achieve outstanding results, it requires a lot patience and some very delicate brush work. It does have the potential for change over time, using the suggested base coat will definitely help. Also reducing the oxide on the surface will also help keep this patina stable. The key to achieving the watery depth, is to use the full range of colours and layers available, so starting with the bronze which should just be visible on high points, this is achieved but carefully cutting back the base coat. The reflective quality of the bronze just lightens the colours added over it, also consider the base coat as part of the palette of colours available and layering the various chemicals over both a stark black background and a slightly reflective background, it gives the patina a real diversity.  A smooth surface really helps and multiple layers of very thin chemical application. The thin layers of oxides are delicate and can with just one misplaced pass with the blow torch be scorched beyond use. 


Metal Preparation

Silicon bronze sanded to a even 120 - 240 grit
 


Base Coat Chemical

 M20 / antiquing solution
 

Base Coat Application

Warm bronze very gently, apply weak solution of basecoat. You want the bronze to change colour gradually, continue applying solution to develop a good even colour. Rinse the surface with water and a brush, this removes some of the residue and helps to neutralise the chemical reaction. Heat the bronze until a fine dusty film appears on the surface, remove this with 120 - 240 grit scotch brite pad or other appropriate soft abrasive. Continue to cut back the back coat carefully with the abrasive, you are trying to achieve a gradual colour transition with the bronze just starting to appear as a background colour on high point. 

 


1st Colouring Coat chemical solution

Water ------ 250 ml
Medium Copper Nitrate solution ------ 1/4 teaspoons
Additional Fixative ----- Weak sodium silicate solution

 

1st Colourcoat Application
 

Heat the bronze evenly, the solution should just sizzle and evaporate away as you apply it with a natural haired paint brush. Take very small amounts of solution into brush at each application, as the brush warms up it natural sucks the solution up into the brush. The iron coloured oxide that forms on the surface of the bronze will the background patterning, so we look to achieve thin veining and natural looking patterning. The oxide is delicate to heat and over heating will darken the iron, you are trying to achieve its most intense colour. Continue to heat bronze and continue with adding the solution very carefully, until you get a variegated even irregular patterning across the surface.  The final pattern should be very subtle, barely visible in places, so although the iron is not obvious, it will develop when a sealant is added and left for a few days to mature.

 


2nd Colouring Coat Chemical Solution

Water ----- 250 ml
Weak Copper Nitrate solution ------ 1 teaspoon
Additional Fixative ----- Weak sodium silicate solution
* This solution needs a few days for the bismuth to fully dissolve

 

2nd Colourcoat Application

Heat the bronze evenly, the solution should just sizzle and evaporate away as you apply it with a natural haired paint brush. Take small amounts of solution into brush at each application, as the brush warms up it naturally sucks the solution up into the brush. The process is the same as the application of the iron, the copper nitrate is very sensitive to over heating, you are trying to achieve a good intense colour on each application of the solution.  Carefully continue to heat the bronze and apply the solution until you get a variegated pattern of colour with the first coat of iron visible in the final patterning across the surface.  Using a soft abrasive, remove any loose oxide that has formed on the bronze surface, this will help the patterning to remain clear and sharp and also by removing the oxide it help to avoid changes in the future.


3rd Colouring Coat Chemical Solution

Water ----- 250 ml
Weak Bismuth Nitrate solution ------ 1/2 teaspoon
Additional Fixative ----- Weak sodium silicate solution

 

3rd Colourcoat Application

Heat the bronze evenly, the solution should just sizzle and evaporate away as you apply it with a natural haired paint brush. Take small amounts of solution into brush at each application, as the brush warms up it naturally sucks the solution up into the brush. The process is the same as the application of the copper nitrate,  on initial application the results are a little underwhelming, the bismuth is barely visible, but proceed as with the copper, working over the whole surface. Using just water, work over the whole surface again and the bismuth and copper will brighten.  The role of the bismuth, is just to create a dusty softening quality and where it forms a denser oxide it will result in a translucent white veining. 


Repeat the process

You basically start right back at the beginning, but increase very slightly the amount of chemicals in each solution, you are looking for a stronger colouration and denser oxide layers forming on the bronze. This stage is all about making judgements about the final colour balance and patterning and everyone will have a prefered outcome. Ultimately it's a really difficult patina to achieve great results first time, but with a little bit of practice, you start to get an understanding of how much of each colour is needed. The key thing is keep the strength of each solution fixed and then its the amount you add with the brush that counts in the final patina. 

 



Sealing Solution

Sculpt Nouveau Smart Coat - 1K Polymer Sealant


Application

When the bronze is at room temperature, we use soft cloth or brush to apply 3 coats, letting them fully dry between applications. 

Highlighting

To add additional colour to highlight areas, we mix a small amount of pigment with a small amount of sealant and use a sponge or brush to add this mixture.

Darkening Shadowing

To create shadows or to darken areas we use a graphite wax, this is thinned down with a clear wax to create a translucent paste. This is applied both under final wax layers or over the final wax layers.


Final Wax layers

We use renassiance wax for the final waxing. Its applied with a soft brush in a very thin layer, left for 10 mins and buffed to a hard finish. We add three or four layers, with the final layer buffed to the final finish.