Gilding on Glass
By
Jim Hingst
A major test of a sign
maker’s creativity and skill is gilding on glass. In this type of signage,
gilding is done in reverse on the inside or second surface of the glass. The
result is a highly reflective, mirror finish.
In
the most basic type of glass gilding, an outline is painted on a window. Then
gold leaf applied inside the outline. The contrast between the color of the
outline and mirror finish of the gold leaf improves the readability of the
graphics and adds visual interest.
“Using a variety of
techniques you can create some unique decorative effects,” says Butch
“Superfrog” Anton. “These include incorporating different shades of gold leaf
or stippling parts of the glass or adding crystal jewels or abalone.”
Surface
Prep for Glass Gilding
Proper prior preparation of
a glass surface is a multistep process that affects both the appearance of the
gild and the durability of the finished product. Failure to remove contaminants
on the glass could cause the gold leaf to flake off of the surface, if not
immediately, then later down the road.
“How you clean the glass
depends on its condition,” says master gilder Joe Balabusczko. “Windows in
restaurants and bars are exposed to a number of contaminants, which can build
up over many years. These contaminants include dust, dirt, paint speckles,
grease and skin oils. Conditions can vary greatly from job to job
and you never know what you will encounter.
So you better be prepared with a variety of cleaners.”
Balabusczko recommends that
your glass cleaning supplies should include a solvent cleaner, such as such as
DuPont’s 3919S Prep Sol or an automotive wax and grease remover, to remove
oil-based contaminants; a detergent cleaner to remove water-based dirt and
isopropyl alcohol for final cleaning. What you should not use to clean glass is
Windex, which contains silicone that can compromise adhesion of the gold leaf.
The first step was to wash the surface with
detergent, such as Simple Green, and water to remove any water soluble dirt.
Next is cleaning the glass with solvent to cleanse the surface of any oils.
Isopropyl alcohol is preferred because it does not leave any oily residue.
These two cleanings may not remove tiny speckles of
paint, adhesive or fly specs on the glass. Usually you will not see these
minute particulates until after gilding, when it is too late.
The best way to remove speckles is with a razor
scraper. There are many types of
scrapers available for this type of work, including
retractable razor scrapers and long handle scrapers. I recommend the heavy duty
Olfa scraper (shown below), which features a four inch blade, great for cleaning large areas
of glass.
To
polish the surface of glass before gilding, gilders will clean the glass with
either cake Bon Ami or whiting. Cake Bon Ami (shown below) is not the same thing as Bon Ami
powder cleanser. Some claim that the powder cleanser can actually scratch glass
and leave a residue. After wetting the gilder’s soap, rub the
surface of the bar with a natural sponge and then scrub the surface of the
glass with the lather.
The gritty Gilder’s Soap is
mildly abrasive, which gives the glass a little “tooth” without scratching the
glass, so the size and the gold leaf will mechanically bond to the surface.
After the lather dries on the glass, wipe it off with a clean cotton rag. Then
scrape off any residue from the surface with a razor scraper. Perform this cleaning at least twice.
While not impossible,
finding the original Bon Ami cleaning cakes in the yellow wrapper will be
difficult. This bar soap consisted of
ground feldspar and tallow soap from rendered animal fat. What made Bon Ami bar
soap great for cleaning glass was that the mineral feldspar, although mildly abrasive,
not only cleaned the surface of stubborn contaminants but also polished the
glass surface.
As an alternative to
cake Bon Ami, you can use gilders whiting powder mixed with denatured alcohol
(also called methylated spirits) to create thin slurry. Lightly apply the slurry with a sponge to
polish and clean the glass surface before gilding. In cleaning, do not apply
pressure, or you could potentially scratch the glass.
When finished
cleaning, rinse the surface with water. After polishing the surface with Bon
Ami cleaning cake or the whiting slurry, wipe the surface down one last time
with isopropyl alcohol and a lint-free cotton cloth or soft paper toweling. To check whether the
cleaning is adequate, you can wet the surface of the glass. If the water beads up on the glass, it’s not
clean enough. Keep cleaning.
Gelatin
Size Recipe for Glass Gilding
In glass gilding, a water
size is the glue that adheres the gold leaf to the glass. Made of water-clear
gelatin and distilled water, this adherent produces a brilliant gold mirror-like
finish. Of course, you could use an oil
size that is used for surface gilding. But the result is a matte finish. Using
both types of gold size on a job can create some interesting decorative
effects.
Gelatin size is sold both in
sheets, which are divided into diamond shaped pieces, and in capsules. Soak two diamonds in a half pint of distilled
water or four to five diamonds for every pint of water for 20 to 30 minutes.
Only use distilled water to prevent any contamination that could cloud the
gold.
If you are using gelatin
capsules, you can substitute one 00 capsule for every two diamonds that you
would use. During this time the gelatin will begin to soften. Heat the water on
low heat until it is steaming hot. As you gradually heat the water,
occasionally stir the mixture using a clean spoon.
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| Glass Gilding tools of the trade. |
Heating the water dissolves
the water-clear gelatin. Once the water is steaming, continue to heat the
mixture for one to two minutes, continually stirring until the gelatin has
dissolved completely. Do not allow the water to boil, because high heat will
ruin the size.
After heating, let the
mixture cool. To ensure that the gelatin has dissolved and no globs are in the
mixture, strain the size through a fine sieve. For every half pint of water,
add a drop of Ivory or Joy dishwashing liquid to the mixture. The dishwashing
liquid will break the surface tension of the glass so the size will wet out the
surface properly.
Water size does not keep
well. Only make enough gelatin size for that day’s work. Do not store the size
that you have mixed for that work day for the next day. By that time, the size may have become
cloudy.
Gold Leaf and the Gilding Process
For
glass gilding, some sign makers use double or triple gold leaf. Just so you are
not fooled, double gold (XX) is not twice as thick as single thickness. It is
about 20% thicker. Triple gold leaf is about 40% thicker than regular gold
leaf. For glass gilding, triple gold leaf (XXX) is your best choice because it
has the fewest number of pinholes and is more opaque and more durable.
Water size is applied to the
glass above the area to be gilded. The
water size is applied with a special brush, called a flat wash brush or size
brush, which allows a steady stream or sheet of size to flow or run down the
side of the glass. In applying the size, don’t hold back. Liberally brush on the size above the area to
be gilded so it streams down the side of the glass. First flood a coat of size
over the entire area. Then reapply the size to the area that you are working
on.
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| Water size brushes |
After wetting the glass
surface, the next step is to apply the gold leaf. Transferring gold leaf with a
gilder’s tip on to a vertical surface is much trickier than gilding a sign that
is lying flat. This process requires
practice.
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| Gilder’s tips |
In laying sheets of gold
leaf in place, work from the left to your right, if you are right handed. By
working in this manner, it is less likely that you will lean against your
work. Left handed gilders should lay
the leaf starting from the right and working left. Regardless of the sequence
that you use in laying leaf, minimize the number of overlapping pieces as best
you can to minimize any noticeable seams in the gilding. You won’t necessarily
want to use full pieces of gold leaf, if a smaller piece will do the
trick. Gold leaf can be cut into smaller
sections. To do this you will need a gilder’s knife.
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| Gilder's Knives |
In applying the leaf, begin
at the top of the letters. After completing the top row, lay the subsequent
sheets below the preceding ones. If the
gold leaf does not lay perfectly flat, lightly blowing on the gold leaf can
help smooth the sheet. Liberally
applying more size above the wrinkled piece and letting the size flow between
the leaf and the glass can also straighten the sheet out.
“Watch what you’re doing
when you apply a second wash of size,” says Balabusko. “Too much wash and your gold can slide down
the glass.” Once that happens, it’s
virtually impossible to put the leaf back in place.” If the gold leaf starts to slide out of
place, you can sometimes stop the slippage by blowing puffs of your breath on
it. Usually, just saying the letter “P” is all the air you need. Touching the leaf with the gilder’s tip for a
second can also help secure the sheet in place.
Applying a second wash of
water size generally will brighten the
luster of the finish and strengthen the bond of the gold to the window. Often
when the gold leaf is first applied, it will appear satiny as you look at the
outer surface of the glass. Do not worry. As the size dries, the gold will
tighten up and the finish of the gilding will become glossier.
“Don’t fret about any small
wrinkles or holidays,” consuls Balabuszko. “They’re inevitable. Most won’t be noticed when the excess gold is
brushed away and patched.”
After the gold is dry, brush
away the excess leaf with a squirrel hair mop brush. A mop brush may seem to be an expensive tool,
but it is a worthwhile investment. Because of its softness, it is much safer to
use than wiping gold particles away with cotton.
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| Squirrel hair mop brush |
If you use cotton, be very
careful. The type of cotton used is
critical to the finished appearance of the gild. Most cotton balls sold in
retail outlets are a very coarse and can scratch gold leaf. Gilder’s cotton is
a softer surgical grade of cotton free of impurities that can dull your gild.
Second
Gild
After removing the excess
gold, inspect your work for holidays.
Holidays are voids in the gilded surface. There are two ways to repair the
holidays. You can either apply more
size and gold leaf where it’s needed or you can do a second gild. Often gilders will double-gild a glass sign,
so the gold is extra thick. Doing a second gild produces a high quality
job. Just make sure that you are
charging enough for the job to cover the additional time and material involved.
Backing
Up the Gold Leaf
After water gilding, you
need to back up your work, painting the backside of the gold with lettering
enamel or a mixture of 1 Shot lettering enamel, Ronan Japan paint and a touch
of Quick Rubbing Varnish. Adding some varnish to the mixture makes the paint
tougher.
Black is often used but it
not the only color to consider. Each color used to back up the gold imparts its
own tone. “Black makes the gold bold,” says Balabuszko. “Yellow makes it
mellow, and red gives it a rosy appearance.”
After the back up paint is thoroughly dry,
you can remove the excess gold. Much of it will come off using a cotton ball or
you can use a Gilder’s Surplus Removal Brush.
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Gilder’s Surplus Removal Brush |
Varnishing
the Glass Gilding
After the back up paint is
thoroughly dry, the last step is to protect your work with window spar varnish.
In coating the backside of your work, overlap the outline or the gilding by
¼”. The varnish provides abrasion
resistance and protects the size from any moisture that could attack the
size.
Conclusion
The
best way to learn the art of glass gilding is under the tutelage of a
professional gilder. After that, it is up to you to practice the skills that
you have learned. With the right training and using professional grade
materials and tools, you are well on your way to mastering a unique skill that
can differentiate you from your competitors.
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About Jim Hingst: After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.
Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer. Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.
Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for publications, such as Signs Canada, SignCraft, Signs of the Times, Screen Printing, Sign and Digital Graphics and Sign Builder Illustrated. He also posted 490 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published. Vinyl Sign Techniques is available at sign supply distributors and at Amazon.
© 2020 Jim Hingst
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