One of my favourite metals to work with, apart from gold-leaf, is copper. This is a great metal to start learning to gild with as it is inexpensive to buy. It can be handled easily and does not require any special tools. The copper comes in large sheets and is a lot thicker than the gold leaf, enabling it to be picked up and placed upon the surface by hand instead of using tips and brushes.
For this exercise, you will need the following equipment:
3 hour gilders size (oil)
Tamping down brush (A cheap make-up brush is ideal).
A book of copper leaf
A cheap brush for use with bleach
In this demonstration, I have a carved wooden horse head that’s been painted in a green paint, that I wish to make look like aged copper. I picked the horses head up at TK Maxx (one of my favourite places to pick up samples to work on). You can of course gild practically anything you like in the same manner. If it can be painted, it can be gilded. However, be sure to prime the surface with the correct paints if necessary.
Here I am applying an oil-based size. In this instance, I am using a 3-hour size. This will mean that the gold will need to be applied within 3 hours. Because of the thickness of the leaf, I shall apply it when the size is a lot tackier than for the gold. This is about 2 hours after application. Today is also a warm day, meaning the size will dry faster anyway. For the application, I am using a standard 1-inch nylon paintbrush. The size is evenly applied over all the surface I wish to coat in copper. The project is a small one, so I shall apply all the leaf in one sitting, instead of staggering different areas.
I am going to apply the leaf directly from the book. The sheets are approximately 14 cm squared.I am firstly placing leaves over the whole surface ensuring no gaps. Many of the leaves are overlapping, but I am not going to worry about waste. The copper is inexpensive and by being generous with its application, the finish will be better. Once the whole piece is thoroughly covered, I have pressed the gold into place using cotton wool pads and a selection of brushes. Make-up brushes in this case, which are a less expensive option than squirrel hair. Care must be taken not to let the brushes or cotton wool touch the size, as it will contaminate the surface and prevent the leaf from sticking very well.
Now the loose flakes of copper are lightly brushed off with a make-up brush. Any areas that have holes have a little copper leaf pressed into them, to ensure complete cover. There are some incised lines in the horse head surface, which the gold leaf is pressed into. There are also many visible line where the leaf overlaps and joins on the surface. For this project, I am desiring these lines, as they will help to tarnish the head at its completion. Care must be taken not to over brush the surface or the agitation could cause the leaf to scratch or tear. If the size is not set enough before application, the copper will easily be removed from the surface. If any repairs of patches or misses need to be repaired, allow the piece to dry for a day and then re-gild these localised areas using clean size and an artist’s brush. The size should just cover the area for repair, and the leaf should be enough to cover the size.
Once all the flakes are brushed off, the copper head is finished! The lustre of the copper has a beautiful depth to it that just cannot be replicated with paints. This finish can be left in its own right of course, but if the colour is wanted to remain, it must be treated with a coating of varnish, cellulose lacquer or shellac to prevent it from oxidising or darkening naturally in the atmosphere. For this piece, however, I desire to give it an ancient patina. After allowing the piece to dry thoroughly over a few days, coat the piece in household bleach. The bleach is applied using a standard 1-inch paintbrush again. It should be lightly rubbed it into the surface.
The paintbrush gives the copper light scratch marks, but this is good because the bleach has a chance to eat away at the copper at these points. Where the leaves have joins and creases is also areas the bleach react with better. After just 4 hours, Verdigris is clearly visible on the surface. The copper will continue to deepen in Verdigris over the coming day, developing antiquity and age quickly and efficiently!
Other household items can also be used to tarnish copper and produce different finishes, including tomato feed fertilizer, hard boiled eggs and ammonia! Why don’t you do a large panel with separate squares and expeiment...
So, now you have seen the basic skills, you can develop these into bigger and bolder projects. The following frame was gilded in exactly the same way as you’ve been shown.
I purchased a large beaten up frame and re-mitred the corner to fit the canvas painting, a copy purchased in a Hong Kong market. I oil gilded it in copper using the 3 hour size and applied the bleach. The inset line in the middle has been oil-gilded in 23.5 karat gold. The bleach does not affect the gold in any way at all. I have not sealed the piece, as I want it to look natural. This effect is after 7 days and I do not expect it to age much more.