At 04:58 PM 8/11/03, Andrew Fildes wrote:
Not quite - this is one of those US-English language problems again!
Technically, 'stained glass' refers to glass that has images painted on
with enamels (paints based on glass powder) and then fused on in a kiln,
This is typical church work where glass pieces with saint's faces painted
on will be used in a leadlight window.
In the US and occasionally elsewhere, almost all glass construction for
windows, lampshades, etc. has become known as 'stained glass' work but
this is technically incorrect.
You are quite correct . . . I was over-simplifying it. Collectively I
believe it should be correctly called "art glass." The term I'm familiar
with for glass that has a single color but is otherwise transparent is
"cathedral" glass. Two more colors mixed in a transparent glass create a
"streaky." The opalescent glass I'm familiar with is transluscent as you
described. A single color is an "opalume" with "opalescent" describing
multiple colors. "Iridescent" describes a rainbow effect achieved by
treating the glass with a coating.
Opal or opalescent glass is made by taking a white or pastel base glass
and dribbling other coloured glasses on to it before passing it through
untextured rollers.
While generally left untextured, it can be; depends on the company. The
exact method of "blending" the glasses together differs depending on the
general pattern/effect desired . . . along with the exact
ingredients. Common glass is made of primarily of silica sand, soda ash
and limestone (and alumina silicate ??). Exact quantities of other
ingredients and specific methods used to create colors and other special
effects (such as "seedy" with bubbles) are closely held secrets even though
the general effects of some additives and methods are widely known.
The better half has bought some smaller pieces of sheet glass from the
factory here. The changing character of it you mention is what makes it
visually interesting. It can look very different backlit versus reflecting
light from other sources . . . angle of incidence also changes appearance.
The result is highly unpredictable, individual and unrepeatable - I have a
couple of pieces that are too beautiful to cut for a project - one like a
japanese traditional landscape in effect. The result is often layers of
colour and it can change character remarkably, depending on how it is lit
- unexpected colours and shapes appear with stronger light.
Density (level of light transmission) for the opal glass can also be varied
and specified (depends on company ??).
It is typically used for lampshades and small pieces like boxes. The most
common type available here is the American Ourouboros glass which tends to
feature a ring mottle effect. These glasses are very difficult to use well
and bloody hard to cut neatly - thank gawd for diamond wheel grinders!
AndrewF
Uroboros (correct spelling) is the trademarked name of a company in
Oregon. They make the mottled ring pattern glass you mention. Your
difficulty in cutting it may be related to how they create it. My better
half has never had any significant problems cutting any of the cathedral or
opalescent glasses she's worked with from the glassworks here, but she's
never used the specific type of glass you mentioned.
Something to experiment with if you need to trim an edge slightly is using
a pair of scissors with very hard cutting edges and immersing the glass
(and scissors) under water. YMMV and strongly suggest you experiment with
some scrap first . . . and some scissors you don't mind pitching if it
damages them. This was passed on to me by one of the hot glass studio
artists. I haven't tried it yet.
Next time I'm there (tomorrow) I will ask about the mottled ring effect and
the color you described. They can make over 22,000 types of
color/density/texture combinations. However, if it is from the Uroboros
company in Oregon and you're fortunate enough to have the number for it you
may be able to order the same exact color(s).
-- John
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