Note: Descriptions are shown in the official language in which they were submitted.
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This application relates to a method of applying a coating
to glass and to a product produced by the method.
BACKGROUND OF T~IE INVENTION
For centuries there has been a demand for coloured glass of
various types to create a variety of visual effects. A classic
example of glasswork of this nature is found in stained glass. The
interest in working with coloured glass continues to the present day
with new techniques and lighting effects continuously being examined.
In terms of utilizing glass as a simple paint support and
applying the paint to the glass, a number of difficulties have
persisted through the years~ The problem of lack of adherence of
paints to glass is one of the most serious of these problems.
Another is the generally unattractive effect created by brush strokes
and overlapping layers of paint when viewed in the very revealing
enviromnent of light transmitted through the glass.
These problems with painting on glass apply to polymeric
type paints such as acrylics. These modern paints are otherwise very
versatile media, providing a major breakthrough in the
characteristics of the colour available to the artist. It would be
very desirable to be able to extend the wide range of paint supports
with which these colours can be used to include glass.
A technique has now been discovered which will allow the
use of acrylic colours on glass and which avoids the problems
discussed above.
PRIOR ART
The applicant is unaware of any prior art material which
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describes any method of applying a fine even coating of acrylic
colour to a glass surface with any degree of permanence. On the
contrary, suppliers of acrylic paints specifically indicate that the
paints are not suitable for application to glass.
_U~MARY OF THE INVENTION
~ technique has now been discovered which will permit the
application of a uniform acrylic paint layer to glass. The glass is
first sandblasted to provide a surface having "tooth". This surface
preparation promotes adherence of the paint to the glass. The paint
is then applied to the prepared glass surface by means of a sponge
applicator. The sponge eliminates brush strokes and the overlapping
created by the strokes.
Accordingly, the invention provides a method of applying a
coating to glass comprising sandblasting the surface of the glass and
subsequently applying to the surface an acrylic paint coating by
means of a sponge applicator.
There is also provided a painted glass surface comprising,
in order, a piece of glass sandblasted on one side thereof and an
acrylic paint coating applied to the sandblasted side of the glass.
DESCRIPTION OF THE INVENTION
_ _ _
As indicated above, a sheet of glass to which it is desired
to apply an acrylic paint coating is first treated by sandblasting.
The sandblasting imparts to the glass a frosted appearance. me
physical effect of the sandblasting is to provide "tooth" to the
glass. The "tooth" consists of a microscopic pitting of the glass
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surface. The pitting leads to the creation of tiny prisms which
decompose and recompose the incident light many times and result in
the frosted appearance. The frosted appearance is purely a visual
effect and does not indicate any interference with the translucence
of the glass.
The paint to be applied to the sandblasted glass surface is
selected by the artist or painter from among available acrylic
colours according to the requirements of the individual project. The
desired effect to be achieved in the product and the environment in
which the product will be placed will influence the choice of paint.
For example, colours must be chosen which are sufficiently
translucent in themselves to achieve a predetermined level of
translucence in the final product. Similarly, colours must be chosen
which are particularly resistant to certain detrimental components of
the environment, such as ultra-violet rays.
Relative colourfastness of various pigments can be obtained
from the literature. One such source is Levison, H.W., Artists'
Pigments Lightfastness and Ratin&~, Colorlab, Hallandnale, Florida
(1976).
The manner of application of the paint to the surface
greatly effects the finished product. Thus, as indicated above, if
the paint were applied by means of a brush, the translucence of the
glass highlights the individual brush strokes and the differences in
paint thickness created by the overlapping of the brush strokes. It
is therefore impractical to attempt to apply an even expanse of
colour through the use of a brush. The present invention
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contemplates the use of sponge applicators. The use of these sponges
on the prepared glass surface results in a very fine and slightly
fuzzy texture and permits the achievement of a visually pleasant
surface and satisEactory evenness where desired. The technique
permits of the application of layers of difEerent colours to achieve
the desired shading and blending while still maintaining the basic
characteristics of fine even texture.
Any synthetic or natural sponge could be utilized for the
invention. For reasons of expense and availability synthetic sponges
would normally be utilized. ~gain, while different sponge textures
could be used for different purposes, a sponge of medium coarseness
will generally be suitable.
The sponges will preferably be shaped to a pencil-like end
area of varying thickness. For example, a range of end thicknesses
could typically be from about 1/4 inch to about 2 inches. The end
area in some cases may be more rounded and in others more elongated.
The preferred manner of applying the paint utilizing these
shaped sponges is by a dabbing technique. The effect generally is to
leave no precise edge marks and so to permit a blending of the dabbed
strokes.
; The sponge will preferably be dampened prior to application
of paint.
In addition to promoting the adherence of the paint to the
glass, the sandblasted surface offers additional advantages. The
prismatic affect of the pitting of the glass surface results in a
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diffusion of incident light which in turn imparts to the finished
product a soft glow and creates the impression that the light is
emanating from the glass itself rather than through the glass.
Furthermore, the finished product is visually very effective in both
reflected and transmitted light. Thus, the effects are very good
from both sides at the same time. This is in contrast to stained
glass.
In the preferred embodiment a colourless acrylic gel medium
is applied to the sandblasted glass surface and allowed to dry prior
to the application of the paint itself. The gel has a higher
adhesivity than the paint and thus promotes the adherence of the
paint.
A further preferred technique is to temper the glass
following sandblasting simply for purposes of added strength.
A further aspect of the invention provides the additional
steps of applying over the coated surface a second glass panel, so as
to provide a space between the panels, and simultaneously or
subsequently evacuating the said space. The product is thus in the
nature of a thermopane window having the interior surface of one pane
coated with acrylic paint.
The absence of any significant amount of air or moisture in
the evacuated space will contribute to the preservation of the
colours.
There has thus been described a new technique which permits
the application to a glass surface of a permanently adhered coating
of acrylic paint having a fine even texture.
