Wednesday, May 27, 2009

24kt Gold Leaf on Glass: An experiment of the electrical properties of gilded glass

Occasionally I have requests from those conducting
scientific research about the prospect
of providing gilding on glass. However,
until recently, I didn’t know whether any of
the traditional binders would interfere with the
required electrical conductivity. I recently had the
opportunity to provide gilding of a large glass
beaker despite the unknown suitability of traditional
glass gilding techniques. The purpose of
my client’s experiment was to repeat in the laboratory
the process by which electricity produces
lightning and to demonstrate that when water
vapor condenses, the condensate is not neutral
but negatively charged.

The first requirement was that the leaf
be 24kt. I chose Manetti double weight purchased
through Sepp Leaf Products in New York.
Although gold leaf can be adhered with a variety
of binders including oil size or glair (egg white),
we chose gelatin dissolved in distilled water as
used in verre églomisé. The rationale for the
choice was that the residual binder remaining
on the glass would be minimized with the small
amount of gelatin used. I used four diamonds
of gelatin to 300ml distilled water.

The beaker needed to be gilded on the exterior
including the bottom with a 1.5" distance
from the edge of the leaf to the top edge of the
glass. I simply taped off a section of the beaker
1.5" from the edge and gilded the glass upside
down. For maximum coverage I double gilded
the glass to allow for a solid covering of gold.
After carefully packing the beaker with a layer
of Saran Wrap and a multitude of cotton balls,
bubble wrap, and packing peanuts, I sent the
beaker on its way and waited to hear the results
of my client’s project. Here is a brief description
of his experiment.

The electrical properties of the gilded beaker
were better than expected. The gold surface is
used to collect water condensate. Ice water is
put inside the beaker to make the gold surface
cold. Dew forms on the gold if there is enough
humidity. This allows the investigator to demonstrate
whether, when water vapor condenses, the
condensate is neutral or negatively charged.
As a gilder, the main finding of interest in this
experiment is that when electrical conductivity
is required, gelatin in distilled water is a successful
method of adhering gold leaf to glass.

(originally published in the Spring 2009 issue of The Gilder’s Tip, the International Journal of the Society of Gilders)