How to preserve the shine on bronze?

I am creating a cloak of 100 bronze leaves to hang in the woods, as the centrepiece of “The Meaning of Trees” event. It's important that the leaves catch the sunlight as the sun moves round the woodland setting. I want the leaves to glint in the light.

Bronze pieces naturally change their colour to brown and then blue over time, see left-hand picture below. In the picture below right, the leaves have just been fettled with a soft wire brush attached to an air driven pen. But they will not stay so bright and shiny for long. The technical challenge is that bronze very quickly becomes dull and tarnished, especially outside in the wind and rain.

I have sought expert advice, but the experts don’t agree! Especially on the choice between wax and lacquer. And then there’s the question of what type of wax or what type of lacquer and how many layers to do.

In my experiments I have treated some of the leaves with wax and some of the leaves with a special lacquer. I have then been putting my leaves outside to see how they change in the weather.

Here is my step-by-step method

Using Tiranti sculpture wax

1. Place the bronze pieces for 30 mins or so in a pickle tank (dilute sulphuric solution that is kept at a warm temperature).

2. rub the bronze pieces with a soft bristle brush and pumice stone powder

3. fettle the bronze pieces with an air driven pen fitted with a soft wire brush (chimney sweep shape)

4. heat the pieces with a hot air gun

5. apply clear wax suitable for furniture

6. let it cool

7. polish with a cloth and very soft brush

8. do this three times

Using car wax

1. One and two above

2. don’t heat the bronze

3. apply car wax e.g. Carnauba paste wax / Turtle wax

4. leave to form a haze

5. polish with cloth and soft brush

6. do this three times

The photo shows just one layer of wax and just over a couple of days the bronze is beginning to discolour. Though this may be attractive if an aged look was required.

Using laquer (Clear Guard lacquer satin Tiranti sculpture supplies)

1. wipe with solvent on a cloth to remove greasy finger marks etc.

2. one and two above

3. don’t heat the bronze

4. mixed 10% solvent into the clear guard lacquer. I used clear guard satin. They don’t supply a glossy finish

5. apply the lacquer mixture with a good quality paintbrush

6. allow one hour drying between coats

7. apply two coats

I like this effect – shiny, but the satin coat is not too shiny, with variations in colour.

I also tried applying a clear gloss lacquer, suitable for some car parts, but I think it became too shiny and brassy looking.

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Click here o find out more about 'The Meaning of Trees' event.