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Glass Identification - Post here for all ID requests => Glass => Topic started by: glassobsessed on January 10, 2012, 02:16:17 PM

Title: How was this hourglass made?
Post by: glassobsessed on January 10, 2012, 02:16:17 PM

I am curious to know how hourglasses like this are made. How do they get the sand inside and how is the tiny hole between the two sections formed?

This particular one is large at 23cm tall but if you used it for your eggs they would end up like concrete - it takes about 45 minutes for the sand to run out. Perhaps it would work for ostrich eggs....

John

Title: Re: How was this hourglass made?
Post by: chopin-liszt on January 10, 2012, 03:02:45 PM

I think 45 minutes is about right for an ostrich egg. Honest!  :sun:
I was watching a programme about non-chicken-egg eating recently!

Title: Re: How was this hourglass made?
Post by: rosieposie on January 10, 2012, 04:16:17 PM

There might be an answer to your question in this, and it makes fascination reading as well.

http://www.hourglasses.com/

Title: Re: How was this hourglass made?
Post by: glassobsessed on January 10, 2012, 05:51:29 PM

I guess a single ostrich egg could feed a few people...

Thanks Rosie, I gleaned that the sand may not actually be sand but could be ground rock of some sort or perhaps even glass, granule size appears to be very important as does purity. Sounds like our ancestors used to 'waste' an awful lot of wine boiling their sand nine times.

The glass vessels shown have plugs or caps on the end so that sand can be added or even removed, this hourglass is completely sealed and as far as I can tell the sand must have been added to one of the chambers as it was being made.

Title: Re: How was this hourglass made?
Post by: rosieposie on January 10, 2012, 06:15:55 PM

I did wonder if someone on that website might have an answer.....is it worth writing to them ?

Title: Re: How was this hourglass made?
Post by: glassobsessed on January 10, 2012, 06:39:07 PM

Worth a try, I will ask, we may need the insight of a glass maker.

John

Title: Re: How was this hourglass made?
Post by: Frank on January 11, 2012, 08:43:01 PM

Blow a long bubble, in this case dip moulded to get the ribs. Transfer to punty and shape it, a small hole left in the end for inserting the sand later, the hole being easily sealed.

Normal sized hourglasses are done entirely at the lamp.

Title: Re: How was this hourglass made?
Post by: rosieposie on January 11, 2012, 08:48:53 PM

You make it sound so simple Frank.....think I'll set up a production line in the shed!!

That one is particularly spectacular though.
Rosie.  :)

Title: Re: How was this hourglass made?
Post by: glassobsessed on January 11, 2012, 09:10:46 PM

Thanks Frank.

So, long bubble crimped in the center, poke a hole with a bit of wire in the middle, add sand and seal up.

Simple, just like Rosie said...

John

Title: Re: How was this hourglass made?
Post by: rosieposie on January 11, 2012, 09:16:24 PM

Quote from: glassobsessed on January 11, 2012, 09:10:46 PM

Simple, just like Rosie said...

John

If only it were!  :usd:

Rosie.  :)

Title: Re: How was this hourglass made?
Post by: Frank on January 13, 2012, 03:00:06 AM

It really is simple and anyone could make them with a few years full-time training.

But I doubt hole is made with bit of wire! Central hole joining two bulbs is formed in shaping to the correct size, I guess it is possible to use a tool of the appropriate diameter to fix the hole size... but I don't 'know', if so some internal flattening may show. Hole for filling at one end would be made with an appropriate tool, probably leaving a raised lip to be folded down for sealing after filling. This one probably had the hole made at the end opposite the punty whereas a lampwork one would still have tube at blowing end and filling done from there.