AE 681 FALL QUARTER 1976
SERGIO GONZALEZ JR.
BRONZE AND ARCHITECTURAL APPLICATIONS
( Condensed from a paper written by )
W. Stiles Winter Quarter 1976
Bronze is an alloy (metal) a mixture of copper and
tin. Discovered very early in the history of Mankind.
It became a universally used materials for weapons and
utensils. "The Bronge Age" referred to the period of
cultural history of Bronze.
The architectural use of Bronze first appeared in
Mesopotamia, Persia and Indochina. It also appeared in
the pre-classic architecture of Greece. Is was used stru-
eturally and decoratively. Also in tools, clamps, dowels,
anchors and many more items.
Early decorative architectural Bronze was used for
example as bands of sheet Bronze which adorn the gates
of the palace of Shalmaneser, a powerful monarch in
It was also found in the doorsteps in the ancient
temple of E-zida at Borsippa. In these steps were ins-
cribed the name of the title of the Babylonian Kings.
Through the years from early man the process of
perfecting the Bronze technique was gradual and consistent
It was not until the Phoenicians appeared that the produc-
tion and trade of Bronze flourished.
The greeks were the first to raise the technique of
casting Bronze to a level of artistic perfection never
equalled. The Romans followed and produced a host of
statues and the first occidental doors as well.
Example 1. The set of doors from the baths of caracalla,
now at St. John .lateran, Rome.
2. The doors of the Pantheon in Rome.
It was also seen in the Bronze girders holding up
the portico and the Bronze plates covering the interior
of the dome. It was later melted down and turned into
eighty cannons for the Castel Sant-Angelo and Bernini's
The doors for the Palatine Chapel at Aachen, Rome.
In 1401 there was a competition for the second set
of Baptistry doors for Santa Maria della fiore, in florence,
(the first set appeared in 1330). Lorenzo Ghiberti won
Ghiberti's doors provided the impetus for raising
the level of Bronze work to one of the highest arts, both
architectural and decorative up through the nineteenth
century and early twentieth century.
But with the arrival of the industrialization the use
of Bronze both architecturally and artistically declined.
Bronze became to expensive and craftsman were declining.
Types of Bronze:
There is a difference between brass and Bronze.
Bronze is a higher class alloy than brass.
Some Bronzes are different in their metallic content:
Egyptian Bronze consisted of 88% copper to
12 onz. tin.
In some Roman work lead was added.
In the time of Augustus zine was adde.d.
Roma esque and Renaissance Minimized tin
increased the zinc.
Tin in Bronzes acts as a Hardner and Strengthener of
copper. When you increase the tin more compressive stre-
ngh is added to the Bronze.
Architectural Bronzes almost always contains 80%
more of copper the rest being tin.
1. Gum Metal
History of Casting Bronze:
Bronze has been mainly cast through the ages,
Many methods have been used in casting Bronze.
Modern Casting Techniques:
Modern technology has logical simplifications of
old methods of casting but the principles remain basi-
cally the same.
One example of a modern technique of casting Bronze:
1. First, clay models are made of the item to be
cast. This model is made at the artists studio
and then taken to the founder .
2. At the founder the first step is to make the
inside and outside sand "cores" which when fitted
together in the "flask" will allow the empty space
between them to be filled with Bronze.
Some of the tools used in casting Bronze, lifter,
oval,, taper & spoon. heat & square, yankee, flange &
Diagram A- Represents the iron flask which confines
the sculptures model as well as the sand
backed around it.
Diagram D- Is the other core.
Diagram H- Sand fills up the rest of the space then the
sand is carefully removed and fitted around
the cast so the spaces can be fitted out.
After the outside core is made, the next step is the
inner core. The reason for this is to form a space into
which the metal can flow to produce a Bronze shell about
one-eighth to one forth of an inch thick. The outside of
which will be an exact replica of the sculpture's model.
Solid Bronze is rarely used because it is very expensive
and it will crack in cooling and is heavier.
The inner core, makes a duplicate the model in sand,
reinforced by supports like the iron bass in diagram"F"
then shave down the surface about (" this is the suspen-
ded in the flsk, and the outer cases are picked around it
in their respective places.
Diagram H- Gates and vents are next formed-gates
for letting the metal in, and the vents
for letting air and gasses out.
Diagram G- The gates are made by cutting away the
sand before it is baked with a spoonlike
tool and painting the sand with "black lead"
to prevent the sand from washing.
Diagram C- Smaller grooves are cut from the space to
be filled with metal to allow the gasses to
The various parts are assembled for trial fit, then
removed and baked in a oven overnight. The object is now
ready for pouring.
Techniques of preparation for casting are extremely critical:
Examples of where this method was used:
After the casting is done the Bronze is now ready for
cleaning and finishing. When the flask is opened, the cli-
nging sand is knocked from the Bronze. The sand has been
burned to a terracotta crispness. The core is removed from
the Bronze by digging and soaking in water. The vents and
gates are cut off and remelted.
Vigorous brushing comes next, later the object is dipped in
an acid bath. It comes out with a reddish glow, and before
the acid has had chance to etch the surface, it is plunged
into hot water for final riddance of acid, sand, etc. Now
the casting is ready for brazing, that is fitting together
the variants parts of a work, such as a screen, by blow
torching the metal until hot enough to melt and fuse toge-
ther with a special alloy acting as a soldier. It also can
be screwed and bolted together. Finally with a pumice stone,
the Brone is polished.
The supreme quality of Bronze lies in its surface
being warm and inviting to touch. It offers the artist a
gamut of possibilities, from a coarse brutal quality of
rough cast, to refinement of a mirror finish.
The natural color of Bronze can be preserved with
varnish. Bronze can also be painted, a process which
happens automatically in the atmosphere but which can
be speeded up and controlled by chemicals. Colors such
as deep black, liver brown, slightly reddish, green or
puple can be obtained.
Application of Bronze:
The employment of Bronze as architectural and decora-
tive elements was to symbolize strength, power, permanen-
ce, wealth and good taste.
Bronze used in other materials
Preservation of Bronze:
On Bronze there is no action comparable to rust on iron.
Thus it is an "eternal" metal.
Is is recommended that Bronze should be cleaned regularly.
1Anderson, Liselette. Bareque and Recoco Art. New Yorkt: Rarry N.
Abrama, Inc., 1969.
7- pkker, Earl P, and Harold S. Langhand. Architectural Metal
1774 EE$ A Washington, D.C. National Association of dr-
99-9 haghatal Metal NAnufacturers, 1947.
3Battereby, Martin. The Decorative Thirties. New York: Walker
and Co., 1969.
Battereby, Martin. The Decorative Twenties. New York: Walker
and Co., 1969.
Saallard, Simpson. The Encyclopedia of Founding. New York: John
Wiley and Sons, 1894.
Buchanan, John P. Practical Alleying. Cleveland: Penton Publish-
ing Cot, 1920.
Burchell, S.C. Age ef-Progress. New York: Time Incorporated, 1966.
) Bush-Brown, Albert. Louis Sullivan New Yorkt G. Braziler, Inc.,
Collins, Benvenute. The Treatises of Benvenate Cellini on Gold-
smithing and Sculpture (translated) b$L 0,R, Ashbee) New
10Ceram, G.W. and Peter Lyon. "The Blue Museum." Herizen, Yel. 1,
no, 2, November, 1958.
11Genorete in Architecture, ne. 63, ChicaBet Portland Cement Ass-
120awn henry J. An Historical Outline of Architectural Science.
Amsterdam: Elsevier Pub. Ge., 1966,
7/-of 13Davey, Norman. A History of Building Aterials, London. Phoe-
MAM House, 1961.
14Dunn, Alan. Architecture Observed. New Yorkt Architectural
Record Beeks, 1971.
150ardner, Relen, Art Through the Ages, New York: Harcourt, Brace
and World, ino, 1970.
16Gebbard, David. The Rickfield Building 1938-1968. Atlantio
eerlings, Gerald K. "The Architect, the Artisan,--and Brenze."
Mail Points, June 1927.
18Geerlings, Gerald K. Metal Grafts in Architecture. New Yorkt
Benanza Books 1957.
ackenbrech, Yvonne (intre.).Brenzes. New York: The Metropolitan
Museum of Art, 1962,
205kedek*, Hanns-Ulrich. Metalwork.. New York: Universe Books, 1970,
21Einsen, Hans Jurgen, ed.: Late Nineteenth Century Art. New York:
NbGraw Hill, 1972.
22Historic Preservation. October-December, 1974.
23de Ka Charles.- "Decorative Work in Various Metals." Architse-
tryggL) segrd4 vol XV, June 1904; vol 16,July, 1904.
24Lewwkes, V.S. Ornamental Metal Work and Contracts., Scranton,
Pa:. International Textbook Ge., 1925.
25Mills, Adelbert P. Materials of Construction.. New York: John
Wiley and Sens, 1926.
bntagu, Jennifer. .Brenzes. London: Octepus Books, 1972.
27N:ewcomb, Rexford, "Brenze and Iron Work-Age Old Handmaids of
Architectural." The Western Architect., October, 1928,
28Raeburn, Michael. An Outline of World Architecture.. Londent:
Octopus Books, 1973.
Stimpson, William C, and Burton Gray. Foundry Work., Chicager
American Technical Society,.1942.
Sturgis, fussell. "A Fine Work of American Architectural Soulp-
ture. The Architectural Record vel XV, ne. 4, April, 1904.
31Vasari, Giorgio, Vasari on Technique. New York: Dover Publicak-
32Welf, Rebert Erich and Renald Millen. Renaissance and Mannerist
Art.. New York: Harry N. Akama Inc. .19bb,
3 elteradorf, Arthur. "Ornamental Iron and Brenze." The Western
Architect, October, 1928.
Cas & ouledGlass:
Sergio Gonzalez Jr.
Glass appears to be a solid but has the same
molecular construction as a liquid. It is composed
of silica, limestone and soda ash. Its best quali-
ty is its translucency and transparency.
The following is a description of how decorati-
ve glass is used and a description of the slides ta-
ken from a final report by
Although leaded glass windows do not define a
particular type of glass to be used, we will see so-
me examples in the following slides, both functiona-
11y and decoratively.
-Slide 44- Window of Priests hous, 15th. century.
You can see in this slide the width of lead
strips were rarely 3/8" and was very pliable and
easy to work with.
Example of lead & glass.
Example of lead & glass.
Example of window patterns & fittings
using lead & glass.
This slide is an example of a more recent
use of lead in windows. Here lead is pla-
ying a major role and the glass is used to
fill the voids.
Example of statement above.
Example of statement above.
In obtaining moulded glass the Architect
is required to furnish the manufacturer
with a drawing or a model from which a mould
is built. The glass is then blown or pre-
ssed into the mould, forming configurations
of the pattern.
In the following slides we will see
how moulded glass can be obtained in
sheets or small cast units, either in
standard patterns or individually desi-
-Slide 52- Example of statement above.
-Slide 53- Example of statement above.
-Slide 54- Example of small units of cast glass, here
it was used to conceal the source of light
and also as a decorative element.
-Slide 55- Example of statement above and relief glass.
-Slide 56- Relief glass.
-Slide 57- Relief glass.
The effect of lighting on moulded glass:
Cast in panels and columns of a variety of shapes
and sizes. Both in solid relief and in pierced grilles
have a wider range of adaptability. They may be built
into lighting fixtures, screens, grilles or wall panels
and can be illuminated either from behind, or with stri-
king effect from above or below.
-Slide 58- Example of light effect on moulded glass.
-Slide 59- Example of light effect on moulded glass.
-Slide 60- Example of pressed glass.
Engraving and Cutting Glass:
"Wheel cut glass" is the method in which a pattern
is formed by cutting and polishing on emery wheels. It
is a method of decorating plate glass models, such as
doors or mirrors, where the pattern is made principally
It is possible to make deep curved incisions with
the emery wheel but difficult to manipulate a large pi-
ece of glass during the process.
-Slide 61- Examples of glass engraving.
-Slide 62- Examples of glass engraving.
-Slide 63- Here we see the artist working on the
emery wheel and engraving.
-Slide 64- Examples of glass engraving.
-Slide 65- Examples of glass engraving.
-Slide 66- Examples of glass engraving.
Max Ingrand and his wife Paule are young French
artists. They have developed this technique of etch-
ing, sand engraving and direct painting of glass.
-Slide 67- Example of their work.
-Slide 68- Example of their work.
Edge Lighted Mirrors:
Mirrors are now being used in ways, namely with
illumination from the edges. This became possible with
the development of interior flourescent neon lighting,
by means of which the light is defused through a whole
-Slide 69- Mirror murals installed by P.P.G. in a Hotel
This process is used in decorating doors, windows,
panels. lighting fixtures and mirrors.
In each case the design or texture required is
produced and impressed on the glass with incised ro-
-Slide 72- Example of rolled glass.
-Slide 73- Example of application.
Glass Bricks or Blocks:
Example of sandblasting on staircase panels.
Example of light fixture.
Example of decorative glass window .
Johnson wax building in Racine, Wisconsin,
by Frank Lloyd Wright.
Polomar telescope mirror, largest cast glass,
in the world.
PRINCIPAL TYPES & SIZES USED IN ARCHITECTURE
AMERICA ARCHITECT~. SEIE "MAERAL IN DESIGN o.2, Marc 19
~ I I _
1__ _1_1111I MA ARhiTEC
TYPE or FORM
APPLICATIONS & LIMITATIONS
CLEAR or COLORED
Lead or Lime
sizes to 18"x 24"- thickness V2"to 2"in
borosilicate 12" x 12"in lead
Any plate glass size, but usually handling
and replacement costs make units under
to to 16 sq. Et. advisable.
Some as etched
Length up to 4 ft. and diameters to
27, in, in borosilicate.
, Length in lead 36.
Used for plasters, Friezes, caps, grilles, lighting
fixtures, etc. borosilicate wherever temperature
lange IS OXtreme
For Rat panels, doors, mirrors, etc.
Same as etched, but commonly limited to designs
composed of straight lines
For balusters, railings, hght Fixtures, etc.
Excessive lengths subject to warpage
Lead or Lime
Obtainable up to72"x120". To reduce
distortion keep length and width needy
equal large mirrored areas should be
divided into smaller units wherever
to 70" x 120" thickness gl to 17 "
To aimphasize space and to reflect 1;ght, Form
Commonly used for shop-Fronts, bathrooms,
Ut;chens, wainscotting, etc. Can be ssnd-
Approx, 6"x 6" to 6"x 8"- thickness I%;'
FLAT DRAWN (window)
Lime or Lead
Lime or Vitreous Silicate
size varies according to thickness. .
Maximum: 210 sq. Et. in V7 stock
Thickness from Ve" to I V2"
Single strength as"x 56". double
strength: 56"x 76"- heavy sheet ao"x rio"
48"x 144"- thickness: to 1%"
varies up to 48"x 144" according to
make and pattern Va" to fu"
46"x so"- thickness: K"to I Yo"
Standard window-glass sizes
40"x 72"- thickness a to 7 mm.
For glazing and mirrors. Mex. clarity and Freedom
For glazing, Distortion limited in highest qualities
For Fire protection, sdety, etc. Sizes usually
limited by Fire regulations
For light control, obscurity. Some pattems have
marked decorative value
For burgierproofing and safety from impact.
Heavier types for bulletproofing
For solaris etc., to admit light of healthgiving
To afford insulation against solar heat
For protection against harmful effect of exposure
to X-ray used in hospitals, etc.
.(R H 1935
whecire thle great discoveries in glass were mlade
1900- 15 Begining of the scientific era of glass-
1910 making and of entirely new concepts of
glass use. America.
1910- 16 Development of heridrisistant type of
1920 glass made possible Pyrex Ovenware,
tough laboratory glassware, and tough
glass parts for use in industry. America.
1920- 17 Continuous methods of melting and
1930 automatic machine shaping of glass led to
arnazmg mass production. America.
1926 18 Pennvernon drawing machine marked
Heatest forward step in centuries of flat
glass manufacture. America.
1930- I9 Class becomes a heat insulation mate-
1940 rial for homes, offices and factories when
successfully made into building blocks,
glass fibers, and foamed glass. America.
1934 20 200-inch Mirror Disk cast for Palomar
1936 21 Class fibers for textiles marketed.
Class :L-.-u:u.a.- produced. America.
1939 22 96% silica glasses and pipelines of
glass made available. America.
1940- 23 Tempered drinking glasses, messware,
1950 mixing howls, refrigerator dishes, pipeline
fittings, glass doors, and rear and side
windows for automobiles marketed. Elec-
trical welling of glass parts. America.
1945 24 Muss production of optical glasses be-
1947 25 Photosensitive glass and electrically-
conducting glass produced. America.
1948 26 Mass production of television tubes
Llanks achieved. America.
70,000 1 Man shaped obsidian, one of nature's
or glasses, into arrowheads, knives and other
earlier instruments or weapons. Place unknown.
3,000 2 First man-made glass, probably an acci-
or dental discovery. Place unknown.
1,200 3 Egypt a center of glass manufacturing.
Pressing in open molds developed.
300 4 Blow-pipe invented. Phoenicia.
200 5 Blowing into molds developed. Rome
becomes a leading center of glassmakm .o
I 6 First glass that was at all transparent'
colorless and relatively free of bubbles
produced. Roman Empire.
1,000 7 Venetians began domination of glass
1590- 8 Microscopes, telescopes and thermom-
1610 eters developed. Europe.
1674 9 Flint (lead) glass produced. England'
1700 10 Casting to get sheet glass perfected.
1790 11 Cood optical glass achieved by stir-
ring pots. I rance.
1879 12 First electric light bulb blown. Amer-
1900 13 First truly successful commercial pro-
duction of flat glass achieved. America
1903 14 Mechanical revolution in glass-making
hegan to take shape. Owens automatic
bottle machine developed. America.
Crystal Glass A colodess glass containing a high per-
ceritage of lead oxide, highly transparent, frequently used
for art or able ware. Often the term "crystal" is a ed as
synonymous with -fine glass." It is relatively expen ive to
make and is considered by many to be the most beautiful
of all types of glass. *
Culled Broken, or scrap, glass. Unlike broken pouery,
broken glass can be remelted and used again. Tlus is an
advantage from the pint of view of the recovery of loses
furnace practice it has been long established that the ad-
dition of a proportion of this broken glass or culletsd
the same compo-ition as the glass to be melled-to the
run intesials in the batch mixture is distinctly helpful,
since it facilitate the melting.
Drawn Glass Class, in sheet, rod, tube, or flament
form, made by continuous mechanical drawing or rolling
Enamelled Glass Glass coated or decorated with an
us aque lines noterial. Probably first developed by the
5macens and the Venetians, and late: produced exten-
ively in Bob mia, Fray e and the United S ates.
Engraving The process of cutting figures, letters, etc.
upon glass by abrasive means. Performed m much the
same may as cutting (q.vO but with more delicacy of
treatment. Fine copper wheels are employed,.and because
abrations of the glass are much shallower, great freedom
f laz ulathnikis as j@ce of glass with hydrofluoric
acid or other agent. generally for marking or decoration,
This acid is also used to obtain obscured glass with smooth,
Finishing Process of cracking off, glazing, grading and
- pgi-hmy glaw after it has been idown. drana or molded.
Flat Glass A general manufacturing term covering sheel
glass, plate glas, and various forms of rolled glass.
Flint Glass The term "flint" as applied to glass should
not be construed to mean that the glass is produced from
flint; it is not. However, when this glass was introduced
by the English. powered flint was used instead of sand,
and bence the name. Today the term is an arbitrary one
--a long-standing trade designation which indicates a
plain, dense, transparent glass of high lead content, such
as is principally used for the manufacture of the finest art
glass and tableware.
Fourcault Process For making drawn sheet glass. Vie
cous glass is drawn through a slit in a fire-chly block
which floats on the surface of the glass in the furnace. The
glass solidifies to a sheet, as it is lifted vertically through
a series of ambestos rollers, being annealed in the proce-s.
It is cut to size, ready for use, as it issues from the top
pair of rollers.
Fluting Ridge-like or rounded vertical lines impressed
in blown glassware by means of a mold. When the lowered
or concase section is wider than the raised or come re-
tion, the glass is aid to be fluted. When the rescue is
Irue. the glass is ribbed.
Amorphous Without ordered arrangement of atoms;
-tructualess: familess, non-cry talline. U ed to describe
glass as a sub-tance.
Annealing A conituled reheating and cooling of a glass
article to remale any stroses (forces) that may have
been frozen in the gla-s by the rapid cooling that co-
eurred as the article wa-- -hoped. To allow fox -, do.
completely formed g!aw ultick, az it leves the inathine
or the hands of the worunan, is paned into af unnel,
partially wheated, and slowly cooled. (See Lehr)
Batch The name given to the mixture of cullet and
larious raw nuanials which is fed in:o the furnace or
tank and is mut
Unt Glass Flat glass that has been shaped by sagging,
wilile hot into rylindrical or other curved shapes.
Hereling (;>inding and yelishing the staface at the
obes to give a sloped harder.
Blow or Any worknuin who forms glass by blowing
either by mouth or wilh <.umpre--sed air. (See Gafer)
Blown Clo-s Glamare -haped 1y air pressure, as by
mouth blowing or by can based air.
Blown Sheet Produced by blowing and swinging the
molten glass to form a cylinder which is subsequently cut
Blow-Pipe A long metal robe, on the end of which the
workman gathers a pl of glass and through which he
blows to expand or >Eape the glass. Pipe or lube has a
rp di.knob at gathering end and mouthpiece at
Cu--ed Glas Plain, tran-parent glass. sometime com-
pletely entered with a layes of colored glass, which can he
cut through by the dec orators to the level of the clear
pl.>- heneath, thus wouring a two-color effect. The glass
is then known as --ease-cut." One or more colored planes
can he thus overlaid upon d primary glass of crystal clear-
m-w and decorated by cutting to yield multi-colored
Casting A process of hoping molten glass by pouring
it into or on anald<, lables, or rolls, 11sed in manufacture
of plate glass and many other glass products.
Charge The glass-forming mixture or "hatch" which is
placed in the furnace to be melled into glass.
Chipped Glass To remove the smooth surface of a sheet
of glow by the action of glue, producing a deculative fein,
like non-repetitive de ign.
Continuous Tank A glow fulnace in which the le\,
of plaw renuties constant because the feeding in of us
materiA continuously replaces the ab-- willnhan,
Crown Glass Flat glass produced by rapidly rotating
molten glass at the end of a rod to form a thin, ylphtly
curved sheet. The original method of flat pla--making,
now seldom used. Largest economical ize is 12" by 10".
6 LOO6Al2Y ~~~
ta~csy c GERPTS PRO: HOW A111~CI co Y'oo ICK 8jrdaN (recoy&f~
Gaffer A mater glaseblower--an artist skilled m l"'
making of glass-head workman of a glass hand when-
Gather (n.) The mass of glass picked up by the hand
shop worker on the punty or blowing iron. (v.I to pl
gla s from a pot or tank on the pipe or punty-
Ghan .\n amoushou- inorganic product of hpion. u mill
transparent or fraw-lucent, consi ting ozthnanly of a who
tion nf -ilicates which has cooled to a rigid condition will
out crystallizing. Gk s is typically hard, usually is brittle
and has a coachoidal t pe of fracture. It may be colork
or colored, and range from tran parent to opaque.
e ty- ;,
Glass Block Hollow blocks of glass formed in two sec-
lions which are welded together by heat and pressure. As
structural units these glass blocks combine beauty, utih:y
and ease of ...il,,,
Glass Blowing The shaping of hot glass by air pressuze.
Gla.w liouse Ibe part of a glass factory in which the
actual wiling and forming of the glass occurs. Also used
as synonym for glass factory or plant.
Glass Tank A melting unit in' which the container for
the nwhen glass is constructed from refractory blocks.
Glaze (Tl.) A smooth, shinmg surface; a glossy coating.
(v.) To furlush with glass. To give a glossy or glass-like'
conting for appearance. To install glass windows or win-
How panes. .
Glazier One who fits panes of glass or one who apples
glaze to pottery.
Glory Hole An opening giving access to the hot interior
of a furnace a ed to reheat the ware m hand-workmg.
Gob (a) A partion of I ot glass delivered by a feeder.-
th) a portion.0f hot g!ass gath.red on punty or vice.
Intaglio A decorative process which is a compromise
between cutting and engraving. In the execution of ordi-
nary agraling, the copper wheel is kept moistened with
oil and center powder which makes possible the rendering
of delicate dedgns on the glass with a luminous frosted
effect. In intaglio the abrasions are made by means of a
wetted stone, which yields a smooth, clean cut, going
deeper than with the copper wheel.
Lehr TIw tunnel-shaped own through which plass ar.
ticle after tlwir funnation by any of the numerous lorn,
ing or --haping process e are passed and subjected to a
low controlled cooling in order to eliminate internal
stre we or tensions. The process is known as unwaline.
Lime Glass A glass containing a submanlial proportion
of lime, usually anaciated with soda and ilica.
Marvering The process of rotating upon a poli had iron
(or sometimes wooden; slab the partially blown glass that
is still soft and but upon the end of a blow-iron. By this
means the shape and thickness of the globule of .wmi-
cooled glass are controlled, and the glass Ls brought into
a proper state of workability for shaping or baring.
Melt A specific quantity of glass made at one time.
Melting The heating process by which the charge is
completely converted into molten glass,
"Metal" The tesm "meral" is used in connection with
mollen glass to indicate the basic glass material-the glass
itelf. When the "hatch" is melted it becomes "metal."
Milleflore Glass Glass made by fusing bundles of var.'
iously colored ad into a solid mass which, when liewed
.on end, di closes intricate and flower-like mosiac patterns,
Made by Humans, Venelians, and glassmuters of many
Mold A form (usually metal) in which glass is shaped,
Murano Glass Glass made on the hland of Murano to
which the glassmaking industry of Verice was moved in
1292. Fine Idown glassv.are has been made there from
11 at day to this,
Pittaburgh Process For producing drawn sheet glass.
Similar to the Foureault Process, but without the use of
the fireelay die.
Plate Class Flat glass of high quality which is cast,
rolled, ground, and polished on both sides. Grinding is
done with sand, graduated from coarse to extremely fine
particles; polishing is done with rouse.
Wheel-out A cut in gla-s made by a molling wheel.
Steel wheels fed unh a carborundum abrasive, are usel
to remove bulk of glass in making first cut at do inex
Stone wheels and felt wheel, are fed with finer aluasire,
such as lin eed oil and emery powder or rouge. and uwd
in polishing rough cuts to brilliant fini b. Copper wheels
are u ed in particularly intricate engrating.
Pot A one-piece refractory container for melting glass.
Open pot: a pot wherein the glass surface is not protected
from the furnace atmosphere. Closed pot: a pot having a
crown protecting the glass from the furnace atmosphere.
Pot Color The homogeneous color developed in glass
melted in a pot; a solid color extending throughout the
Pot Glass A high-grade brand of glass, such as the
"lead crystal." Class of this nature is necessarily made in
small quantities, with all the care that can be devoted to
it in order to maintain its purity and brilliance.
Press and Blow A process of glass manufacture in
which both the preliminary form and the finish are pressed
and the preliminary form is blown to achieve the final
Pressed Glass Classware made by dropping molten glass
into a mold in which shape is imparted to it by plunger
action. Both plain and ornamental glass is now produced
by this means, and usually the entire decoration is yielded
Prunt Small blobs of glass applied to the surface of a
glass object into which seals, names or initials are im-
pressed either as decorations or to provide identification
(See Ravenscroft goblet, page 75)
Pull The quantity of glass delivered by a furnace in a
Pumice A hardened, spongy or cellular volcanic glass
froth used for smoothing and polishing.
Punty An iron rod used for gathering and manipulating
the hot glass-frequently used to remove partly formed
glass object from blow-pipe.
Ravenscroft Glass Class made by George Ravenscroft
an English chemist (1608-1681) who produced the first
clear crystal-like lead glass. Today, examples of his work
are extremely rare and valuable, especially those pieces
which bear his seal of a raven's head impressed on a
prunt of glass.
Rolled Glass Produced by pouring molten glass on the
flattening table and rolling to required thickness. Plain
sheets me polished on <>ne side and dull on the rees e.
Certain Ex pes of ophthahnic glass are made by this prove .
Sand A hard, granular rock material, finer than gramet
cources than dust, and containing little or no organic mat-
ter. "1. : sands consist largely of silicon dioxide,
or .1.. ....r ... found either as banks of loose sand or
:0 the form of sand tone.
Sandblasting Blaising fme quality sand onto glue to
obtain a rough-textured and obscured sheet, and for deeply
engraving patterns with die aid of protective stencils,
Sculptured Clusic Omainental glass which gives an
intaglia or Las-relief impression and is made by casting
in molds made directly from the sculptor's chy original.
Has all the characteristics of the original including tool
. marks and any textue the artist may apply. Glass sculp-
tured in the round is abo called sculptured glass.
Suda-lbne-silica Glass Cananonly known 'as "lime"
glass. This is a term that is generally used to denote the
ohical and roost widely used type of glass. It can be whed
in mass quantities in large tanks, thereby facilitatirag the
production of low-< 1 articles such as bottles and food
Stained Class A colored glass, the substance of which
has been hady-colored in the process of manufacture.
St.. :od glass windows use both glass with inherent color
and class that has had color stained or fixed on its surface.
Stress Any condition of tension or compression existing
within glass, particularly due to incomplete annealing,
temperature gradient, or lack of homogeneity.
Structural GMs (1) Flat glass, usually colored or
opaque, and frequently ground and polished, used for
structural purposes. (2EGlass block, usually hollow, used
for structural purposes,
Tank Glass A term which embraces those types of glass
produced in mass quantities for manipulation chiefly by
automatic means. At one time "tank glass" implied glass
of an essentially cheap type such as inexpensive bottle
glass. Nowdays, however, the significance of the term is
broader, since tank-melling procedure has been revolu-
tionized, and many types of articles for domestic purposes
are now being made from glass melted in huge tanks on
the continuous plan and shaped by fully automatic
Translucent Glass Cla-s in which micro-capic, who
less particles bend light rays at all angles -0 that Man-
mitted Eght i-- allowd and objects runnot he clearly -,-en
through the glass.
Transparent Class Permitting light to pa-.. freely, whb-
out scattering and without noticeable ah-orprion, so that
lothes can he distinctly won through the tran-pan-nt
material. Most glass, as we know it, is unn-pmeal .nal
permanent transparency is an extremely valuable chur-
acteristic of glas .