Saturday, December 31, 2011

Skills Development: Good as Gold

I have been fortunate this year to be able to take almost a month off from regular scheduled work for skills development. There are things I wanted to brush up on, alternative techniques I wanted to try, and new skills that I wanted to gain.

I've spent time hand cutting dovetails, sprucing up on french polishing, hammer veneering, trying new veneer patching methods, learning lipase enzyme cleaning formulation and application, gained greater insight into the use of ultraviolet lighting for examination, and finally began gaining confidence in gilding.

This month has been really different from the hustle and bustle of working on client projects. It's been nice to regain perspective after this year's busy season by taking a breath and slowing down for a few weeks.

Here is one of my projects from the past month:

Oil/Mordant Gilding

It is not uncommon for a furniture restorer/conservator to encounter a gilded surface on objects entrusted to their care. Not having a certain level of comfort handling these situations can be a great hindrance to a satisfactory and/or comprehensive treatment.

Back in fall time, I spent some time with a friend Colin Barclay, landscape painter. Colin fabricates and gilds his own frames for his paintings. He was gracious enough to give me an introduction to the craft. Building on that experience, I have been reading much since then. It was not until this month that I was able to carve out some time to bring it the bench.

I had a few legs from a discarded sewing table lying around and thought they would make suitable test substrate for the trials. Even though it is not necessary to have gesso underneath oil gilding, I wanted to try both oil and water gilding on the same piece so I decided it would be great practice to gesso the entirety of the leg. The process starts with sizing the surface with rabbit skin glue (9 parts water to 1 part granules). To make the gesso, mix calcium carbonate into the rabbit skin glue mixture until it gets the consistency of heavy cream. The gesso is applied to the sized substrate with carefulness not to obscure the carved/turned details. You will know when to apply the next coat of gesso when the drying surface begins to turn from a grey to white on the high spots. This usually occurs within minutes.

Usually, 3-6 coats of gesso are applied. This will give you enough thickness to sand it down to a smooth surface. When the gesso has dried after 24 hours, you can begin to sand with 220 grit sandpaper until the bumps, pits, and irregularities are mitigated. Following the sanding, a damp cotton cloth is used further smooth out the texture.

Now that you have the smoothed gesso surface, you can seal it with 1# cut shellac. (This is not done with water gilding.) The sealing prevents the oil size/mordant from being soaked into the gesso too much. When the shellac is fully dry (an hour or so), you can apply the oil size. I used Rolco's Quick Size. This is said to be ready to gild in 1-3 hours as opposed to the 12 hour wait time of slow dry size. (Mine was an hour and a quarter.) The size was applied with a 1" squirrel hair brush.

The goal is to make the mordant as smooth and brush stroke-free as possible. Once sized, the piece is set aside in a dust free environment to set up to be ready for gilding.

The mordant is ready when your knuckle lightly touched against the surface is not pulled and when the size makes a squeaking sound when your knuckle is dragged across it.

Gold leaf is thin. Very thin. 1/125,000th of an inch thin. You cannot pick it up with your fingers without talcum power or it will fall apart. For this project, I used Monarch "French Pale" 22kt gold leaf. In order to transfer the leaf from its book onto the object, a tool called a "gilder's tip" is used. A "gilder's tip" is a row of squirrel hair glued between two pieces of cardboard. The squirrel hair is lightly brushed against your skin or hair to pick up oils used to grip the gold leaf. Some people have said that it is static electricity that picks up the leaf, but this is a misunderstanding. When the tip is ready, it is gently placed onto the edge of the leaf and picked up. Don't breathe. Don't make any sudden movements. Don't let any drafts in your studio. The slightest breeze will send your leaf flying into a crumpled mess.

The leaf is gently placed onto the sized surface. When the leaf touches down, it's there to stay so it’s important to make sure to line it up correctly before laying it down. On low spots of carvings or turnings, you can use the skewings (unused fragments) to fill in any holidays that appear.

After all holidays are filled, you can use a stiff bristle brush to lightly knock down any wrinkles on the surface. Finally, soft cotton can be used for a final rub to achieve your sheen.

On this piece, I decided to patinate it to simulate the experience of in-gilding on an antique object. The patination begins with a light solvent wipe to remove gold from high spots. I used VM&P Naphtha for this. The leg was then coated with a pigmented 1# cut shellac followed by pigmented wax applied and left in the recesses. The result was an appropriately worn and patinated gilded surface.

I thoroughly appreciated the experience and have gained considerable confidence with the craft. I look forward to trying out in-gilding using a reversible mordant like Acryloid B-72 Jonathon Thorton discusses in his excellent paper, "The Use of Non-Traditional Gilding Methods and Materials in Conservation" in Gilded Wood: Conservation and History.

Further Reading:

Marx, Ina Brosseau, and Allen Marx. Furniture restoration: step-by-step tips and techniques for professional results. New York: Watson-Guptill Publications, 2007. Print.

Mactaggart, Peter, and Ann Mactaggart. Practical gilding. London: Archetype, 2002. Print.

Rivers, Shayne, and Nick Umney. Conservation of furniture. Oxford, England: Butterworth Heinemann, 2003. Print.

Bigelow, Deborah. Gilded wood: conservation and history. Madison, Conn.: Sound View Press, 1991. Print.

Chambers, Donald L.. How to gold leaf antiques and other art objects;. New York: Crown Publishers, 1973. Print.


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