In article ,
David Billington wrote:

Joseph Gwinn wrote:
In article ,
David Billington wrote:


Joseph Gwinn wrote:

In article ,
"Jim Wilkins" wrote:



"Paul K. Dickman" wrote in message
...


"Joseph Gwinn" wrote in message
It is not breakage. The strongly alkaline automatic dishwashing
detergent
will etch the surface and they will loose their shine. It will etch
regular glass to, just not as fast.

From wikipedia
Lead crystal should not be cleaned in a dishwasher as the corrosive
effect
of dishwasher detergent is high on such types of glass-that is, it will
quickly go 'cloudy'.
http://en.wikipedia.org/wiki/Dishwasher

Paul K. Dickman


I've seen KOH in boiling ethanol etch Pyrex cloudy in a few minutes.


That's pretty severe, but ordinary dishwashing isn't nearly that
extreme. We use the lead crystal wine glasses two or three times a week
so those glasses have been washed at least a hundred times over the last
year, for a few years, and they do not appear to be etched. I'm sure
they will eventually dull, but it won't be fast. And, I'll surely
break them by accident long before.

Joe Gwinn


How do you know they're lead crystal, any indication what brand are
they.


They are Riedel, and were marked as containing 32% lead.


That is good, IIRC in Europe it can only be called lead crystal with 24%
PbO and above. IIRC a friend uses around 30% lead crystal for what she
blows in her studio.

Yes. That seems to be the sweet spot for lead glass.


A good indication of lead crystal is it appears grey when looking
through a thicker section in much the same way window/float glass
appears green.


I have not tried that, but will. I don't recall any green color in the
base, where the glass is thickest.


The green colour is in float glass and is is due to iron impurities and
you see it through thicker sections. Lead crystal has a grey cast to it
when viewed through thicker sections although sometimes not obvious
unless compared against a clear item.

When tapped, they do have a low tone.



Yes lead crystal is supposed to ring better than more common soda lime
glass.

They do! For a given thickness, lead glass will have the lower tone.
The resonant frequency is the square root of the mass density and the
mechanical stiffness. Lead glass is very strong, so the sections can be
thinner, which confuses things a bit.


The stuff certainly isn't used much any more due to the
safety concerns and in art glass I've been told its use is non existent
in the US and in UK/Europe is becoming much less common. A couple of
blowers I know use it as they do a lot of restoration work and cold
workers prefer it as its much softer and easier to work.


Not much used? Hardly. Many tons of lead crystal are sold every year.

http://www.mieleglasscare.com/intern...nglish/sites/g
lasserien.html

http://www.shopzilla.com/wine-glasse...stal+lead+wine
+glasses/313/products

http://www1.macys.com/shop/product/r...ollection?ID=1
48803&cm_mmc=Google_Feed_AU-_-6-_-75-_-MP675


Well, that's enough links. Lots of lead crystal is sold.


Joe Gwinn

Lots of lead crystal sold, but is any of it made in the US? I've been to
the Dartington factory and they don't make as much there anymore due to
cheaper competition from abroad, also health and safety with the lead.

I don't know how much is made in the US, although lots of people buy
Reidel, which is made in Germany. It's certainly the case that people
have gotten crazy about the dangers of lead. And mercury. And life.


Some years back they installed an enormous extraction system to pull off
the fumes from the furnace and collect the lead oxide.

This makes sense. While the glass isn't such a danger, the process to
make it may require containment.

Joe Gwinn