Ask A Scientist© Environmental Earth Science Archive

name         Warwick H.
status       other
age          50s

Question -   Are glass sinks practical?
I observe that glass sinks and basins are in increasingly in vogue in some
houses. I shudder to think what can happen if hot water, which is set to
boiling point in most houses these days, is allowed to pour into one. Are
they all they are cracked up to be, as I might put it? Will glass
withstand such temperatures? How so?? Also, from what I have seen, the
metallic fittings which are attached to these glass sinks react
differently to glass as regards temperature change. Another conundrum. Am
I cracked?
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Well, part of it depends on the glass.  Borosilicate glass, among other
types, has very good high-temperature properties.  Laboratory glassware and
baking dishes can be made out of it.  Borosilicate does not expand very much
when heated (or contract much when cooled), so it tends not to crack from
uneven heating.

Also, domestic hot water usually is not all that hot.  It is often hot enough
to burn skin, but that is nowhere near boiling.  Domestic hot water is seldom
hotter than 70 Celsius.  On an absolute scale, 70 C is only 25% hotter than
0 C.

You are correct that metal and glass expand to different degrees when
heated.  This certainly is something that designers need to consider when
making glass sinks.  Metal and ceramics expand differently when heated as
well, so the same consideration is required when making sinks and other
fixtures from the more familiar porcelain.

I would expect that the biggest problem with glass fixtures compared to
porcelain ones is that scratches and water spots would be more obvious.
They'd probably look great as long as they're never used!  Maybe for the
guest bathroom?

Richard E. Barrans Jr., Ph.D.
Director of Academic Programs
PG Research Foundation, Darien, Illinois
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