Restoration & Stencil Making Part 3:
Part one of this series
covered a technique for creating high quality artwork for a painted
clock tablet. Part two covered a technique for transferring the
background and fine-line detail of the artwork onto the glass by
creating a full sized decal. The clear cells defined by this
background can then be filled with
appropriate color to complete the tablet design.
provided here will show a second technique for getting the image
onto glass. The difference however is that
the technique presented here shows how to produce a very accurate
silk screen and use it to apply the background paint and detail
lines. This technique, while more complex than the decal method,
produces a finished tablet that is very close to the original in
terms of production method and materials
Making a silk
screen using traditional methods is a relatively complex process involving building a "screen"
over which the silk is stretched and attached. The silk must then be
treated with a special emulsion to become light sensitive. It is
then exposed to light to transfer the image from a "mask" to the
screen. Finally, the screen must be cleared of unneeded emulsion to
create areas where paint can penetrate and areas where it is
blocked. Obviously, for the occasional user, this is both a complex
and fairly expensive process.
are now high-tech silk screen materials that are pre-treated with
the light sensitive material and are ready for exposure and use. One
such produce is called
. It is available directly from the
materials make creating a high quality silk screen easier than ever
before, they are precise products that require that the
instructions be followed carefully. This presentation will cover the
steps to creating a silk screen using the PhotoEZ product. The
silkscreen is then used to transfer the image to the tablet glass.
MATERIAL SELECTION: PhotoEZ silk screen material is
available in two grades: Standard and Hi-Resolution. Standard has
110 threads per inch while Hi-Resolution has 200. It's tempting to
go immediately to the Hi-Res for the greater image clarity, but that
could be a mistake.
Good silk-screening is
about getting paint through the screen. It will be more difficult to
get paint through 200 threads per inch than 110. As a result,
getting good (opaque) coverage on clear glass can be a challenge
with Hi-Res unless using special screen printing ink.
provides plenty of image resolution for all but the most detailed
designs. It should be adequate for almost all clock tablet jobs. You
will find it much easier to get good coverage with Standard than
with Hi-Res so, unless the job requires it, stick with the Standard
Screen printing involves
learning several new skills and working with new materials. It is recommended that a relatively small project be undertaken until
you become familiar with the techniques. This saves material and
allows you to complete a number of practice pieces quickly.
Making a screen of
just a portion of your project tablet image is a good way to master
the specific techniques needed for the job at hand. Here, a screen
of just 1/4 of the total tablet has been created for test and
Creating a number of sample pieces on scrap glass is a good starting
point. Working with these, it is possible to determine the correct
angle for using the squeegee, the correct consistency of the paint
and other important variables before beginning the actual tablet.
MAKING THE SCREEN: In order to make a
silk screen stencil, a "mask" is needed that will block light from
passing through in some areas and allow it to pass through freely in
The easiest way to make
a high quality mask is to use the original artwork produced in
Part-one of this series to make a transparency.
material that works with a regular copier is available from most
office suppliers or if you only need a single transparency, you can
get it at a quick-copy store such a Kinkos.
transparency is a full sized copy of the original artwork. The black
areas will be the part of the silk screen that allows paint to pass
through. The clear cells on the transparency will be solid areas on
the screen to block paint. The solid areas
also provide attachment of the silk screen to the glass.
If you look at the
transparency with the above in mind, it will become obvious that
there will be no solid areas around the outer perimeter of the silk
screen and therefore no attachment points around the border. This
will not work well.
To provide an attachment
strip around the outer border of the silk screen, approximately 1/4"
is trimmed off all four sides. This means that when the mask is
placed on the silk screen material, light will hit this 1/4" border
(like it does the clear cells) and a solid border strip will be
Next, an exposure fixture that will hold the
mask firmly against silk screen material while it is exposed to
light is needed.
The simplest fixture is
two pieces of clear glass with a tape hinge holding them together.
Obviously the glass needs to be large enough to hold your silk
screen project. Normally, two pieces of glass 10 x 12" works our
Place a piece of black
card stock on the bottom glass to prevent light exposure from the
screen material is a very precise, high-tech product. Detailed
instructions are provided with each order. Study these instructions
and follow them closely to produce a high quality silk screen.
Working in a dim room, remove a piece of the light sensitive PhotoEZ
material from its black package. Use a ruler and scissors to trim
the piece to the same size as your tablet glass.
The silk screen
material has a thin plastic sheet attached to it that must be
removed before exposure. Use a finger nail to lift and remove this
sheet from the green silk screen material.
Place the silk
screen material on the black paper of the exposure fixture with the
shiny side (the side you removed the thin plastic from) facing up.
Position the transparency onto
the silk screen material making sure it is centered so there is a
green border showing on all sides.
the top glass onto the mask/silk screen sandwich.
Place a thick towel over the
glass to prevent light exposure when you leave the dim room.
Exposure of the
silk screen is best accomplished using bright sunlight (high-noon). A
watch with a second hand is needed to do a precise exposure.
Place the exposure
fixture on a sturdy platform in a shade-free area then remove the
Time the exposure.
Normally, in strong sunlight, exposure takes about 30 seconds. Do
not over expose or light may seep through the masked areas making it
more difficult to remove the emulsion in these areas. Follow the
directions that come with the material...
When the exposure time
is up, quickly re-cover the fixture with the towel and immediately
remove from direct sun light.
To process the
exposed silk screen, it is placed in a dish of cool water for
approximately 10 minutes.
Notice that the areas
exposed to light are noticeably darker than unexposed areas. This is
one way to tell that the exposure has been successful.
Once the silk screen has
soaked for about 10 minutes, the green emulsion on the unexposed
areas of the screen will soften. Carefully lift the screen and turn
it so that the emulsion side is now facing downward.
Use a soft brush to
remove the green emulsion from the screen. Brush only on the side of
the screen opposite the emulsion (i.e. the side now facing up). This
will prevent accidentally lifting any of the emulsion from the
Brush gently and rinse
the silk screen often. As the emulsion is brushed away, only the
white woven material will remain in the areas that were unexposed.
The woven material will allow paint to pass through while the areas
which still hold emulsion will prevent paint from passing.
Inspect the screen very
carefully to ensure that all of the unneeded emulsion has been
brushed away then rinse one final time.
that the screen has been completely cleared, place it back in the sun with the emulsion side facing
up. Expose it for a minimum of ten minutes to harden the remaining emulsion.
The silk screen
is now completed. It is a highly detailed stencil that
can be used many times. Place it in a safe place until needed.
ATTACHING THE SCREEN:
To use the screen, it must be firmly attached to the glass before
paint is applied. To ensure a good seal, it is important that the
tablet glass be clean and free of finger prints.
the tablet glass with Bon Ami and water. Make sure both sides of the
glass are free of dirt, oil and other contamination.
Just prior to
applying the silk screen, wipe the clean, dry glass with acetone and
a clean towel.
A good seal
between the glass and screen is essential for a sharp image. One
approach recommended by the screen maker is to dampen the screen,
place it on the glass emulsion side down. Smooth the screen against the glass with a finger or
squeegee and allow to dry.
The green emulsion
layer becomes slightly tacky as it dries which helps it to adhere to
the glass. This is the preferred method since there is no chance of
accidently clogging the tightly woven screen material thus
preventing paint from passing through.
If you encounter
bleed-over when using the screen dampening method, you can
Repositional Stencil Adhesive to achieve a stronger seal. This
is a special adhesive available from a number of sources including
Lowe's home stores.
It should be used
very sparingly to avoid clogging the screen. Hold it approximately
one foot above the screen and lightly mist the screen. Allow to dry
for at least two minutes before applying to the glass.
With the screen
correctly positioned on the glass slowly go over every inch of
the screen using a finger to press it down against the glass. Pay
particular attention to areas where there is fine-line detail. These
are the areas where bleed-over most commonly occurs.
INKS & PAINTS: Glass, being non-porous, is more difficult to
successfully screen than items such as T-shirts. On glass the paint
or ink must be thin enough to pass through the screen but thick
enough to avoid bleeding under the screen causing a fuzzy image.
Frankly, it takes a bit of practice to sort out the best paint and
the best technique.
There are several
produces available for painting onto glass, but these don't
necessarily work well for screening.
Pebeo Vitrea 150
Acrylic paint is made for use on glass and ceramic surfaces. This paint tends to be thin which is fine
for brush work, but sometimes leads to bleeding when used on a
screen. Also, Pebeo 150 black is only available in a transparent
PermEnamel Airdry Paint by Delta, available from Michaels Arts & Crafts,
is a product made specifically for use on glass. It is thicker than
Pebeo but may still be somewhat thin for squeegee work. If the
screen is well attached to the glass PermEnamel may work well for
Naz-Dar 59-000 Series
Gloss Enamel from DickBlick.com
is a special silk screening ink that is designed for use on hard
surfaces such as glass. Unfortunately, it is fairly
expensive at around $20.00 per quart and requires the use of a
special solvents for clean up. If you are doing only a few tablets
per year, the cost is prohibitive.
paint, in the thick,
creamy form, is personal favorite. Readily available brands include Liquitex high viscosity acrylic and Academy acrylics by
Grumbacher. Both are available from art and crafts stores such as
These work well when thinned slightly with acrylic medium.
Additionally, the screens can be cleaned up with just soap and
Water based Acrylic
offers a valuable advantage when working on clock tablets. The clear
cells will usually be painted with oil-based paints (metallic or
solid colors). If the black background and fine-line detail had been
created using an oil based paint then the oil-based color coat
would likely soften the background paint creating a bleeding
problem. Fully cured acrylic will not be affected by application of
an oil based paint over it.
There are many
techniques for pushing the paint through the screen and onto the
glass. The most common method is to spread a line of paint along one
edge of the screen then use a plastic "squeegee" to pull a line
across the screen pushing paint downward through the screen.
With the screen aligned and attached to the glass, a line of paint
is spread across one end of the screen. As noted previously, when
using artist's acrylics thinning with about 1/3 acrylic medium
usually improves the coverage. Mix in a plastic cup then spread with
a spoon or flat stick.
Use the squeegee
to draw the line of paint across the screen in a slow, smooth
motion. It is not necessary to apply heavy downward pressure on the squeegee.
on to glass, the technique used with the squeegee is very important.
The squeegee should be held at an angle of around 45~60 degrees from
the glass. A steeper or more shallow angle tends to force paint
under the screen and cause bleeding.
pass from one side of the screen to the other. Turn the squeegee
around and complete a pass back across the screen. Continue to apply
light, even pressure and move slowly.
tendency to sweep the squeegee back and forth in a paint-brush
motion. This will push paint under the screen.
Make a third
and final pass from one side of the screen to the other then set the
squeegee aside. It will likely have quite a bit of paint on it.
Carefully lift a
corner of the screen and gently peel the screen from the glass.
If everything went well, the image will have been transferred to the
glass in crisp, bold lines. Set it aside to dry for several hours.
Inspect the dried
screen carefully to ensure that coverage is complete. It is common
to find some areas where the paint was lifted when the stencil was
take away. These tiny "holidays" can be filled using a small brush.
Also inspect all of the
fine-line detail. If there is any drop-out, use an artist's
brush to touch up.
If there are any
small areas of bleed-over, they can be removed with a swab or hobby
With the black
background pattern in place, color can now be added in the clear
Once the color is
added, an additional layer of backing will be added. This will make
the black background more opaque as well as provide protection to
the fill colors.
Part four of this series covers adding color and backing.
Click the link
to proceed directly to
Silk screening is a very accurate method to get a painted image onto
a tablet glass. This technique produces a finished tablet that is
quite close to the original. It is a very useful approach for us
"non-artist" to get a highly detailed tablet image accurately
transferred to a tablet glass. With the image background as a guide,
it becomes much easier to complete the tablet whether a colorful
design or a basic gold and black design.
The new materials
available for creating a finished silk screen are fairly easy to use
and produce very fine detail. The results possible can be very
impressive. It's worth giving it a try just to see what is possible.