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| Deering
Library Foyer Chandeliers |
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Northwestern
University - Deering Library - Evanston, IL
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Lumenelle Solution: |
| 1) |
Replace
all Large Globes – 18 pieces = 5 ¾” dia. x 11 ¾” height |
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(
Metal ring inside diameter = 6 3/8” ) |
| 2) |
Replace
all Small Globes – 36 pieces = 3 ¾” dia. x 11 ¾” height |
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(
Metal ring inside diameter = 4 1/16” ) |
| 3) |
Replace
all Sleeves – 18 pieces = 5 ¾” dia. x 4” height |
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(
Metal ring inside diameter = 6 3/8” ) |
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| Before |
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After |
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Problem: |
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Missing
Glass Globes – 2 sizes |
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Missing
Glass Sleeves |
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Solution: |
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Replace
All Glass Sleeves and Globes |
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Problem: |
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Original
Glass Has Become Fragile |
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Solution: |
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Replacements
Are Borosilicate Glass |
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Notes:
1)
Client wanted heavy clear frosted (sandblasted? as opposed to milk glass
to improve light transmission thus saving energy.
2)
Sizes were matched to original glass pieces supplied by the client. |
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| Three
different materials were evaluated as replacements for the broken chandelier
glass: |
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| OPTIONS
EVALUATED: |
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CONCLUSIONS: |
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| 1) |
Borosilicate
Glass |
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Borosilicate
glass combines high heat resistance with high stability against chemical
aggressions. The long-term service temperature is around 450 ° C. Borosilicate
glass is commonly used in laboratory glassware, cooking dishes, and bulbs
for high-power lamps. |
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Borosilicate
Glass balances economy, appearance, and durability. As a result, Lumenelle
suggests the use of sandblasted or etched borosilicate glass for the replacement
globes. The glass would be a clear frost for maximum light transmission
and would not have the milkiness of the original glass. Lumenelle
has provided a quotation accordingly. |
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| 2) |
Lead
Crystal |
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Lead
glass has a high refractive index. Lead Crystal is commonly used in art
glass and adornments on chandeliers. |
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Lead
Crystal is heavy and relatively fragile. Over tightening of the screws
intended for holding the glass in place could relatively easily crack the
lead crystal. Normally, the lead crystal used in chandeliers are either
small pieces and/or large pieces are supported underneath. While lead crystal
would be the most attractive of the three options, the chandeliers should
be modified to provide support from below of the lead crystal pieces. |
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| 3) |
Polycarbonate |
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Polycarbonate,
an extremely strong plastic, is naturally transparent, with the ability
to transmit light nearly that of glass. It has high strength, toughness,
heat resistance, and excellent dimensional and color stability. Commonly
used for plastic lenses for eyeglasses, vandal-proof windows and light
globes. |
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Polycarbonate
is capable of providing parts visually indistinguishable from glass. Three
aluminum molds would be required making initial investment high. If all
parts were the same or there were more chandeliers requiring replacement
glass, this could be an attractive option in terms of cost. Polycarbonate
has only fair chemical resistance and is attacked by many organic solvents.
Polycarbonate is sensitive to ammonia, so glass cleaners like Windex should
not be used on polycarbonate. |
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The
resistance of soda-lime glass, the most common commercial glass,
to sudden temperature changes is comparatively poor and therefore was not
considered. |
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For
more information about Lumenelle restoration contact
us by email or phone.
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