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Author Topic: How can I achieve a hydrated look in glass?  (Read 6333 times)

Offline DIVERDOWN

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How can I achieve a hydrated look in glass?
« on: 24/05/2010 00:30:03 »
Diverdown  asked the Naked Scientists:
   
Dear Chris,

I am not a scientist but I am medical personnel so I have some basic knowledge of how chemistry works.  Here is my dilemma- in addition to being a paramedic I am also an artist.  I have been working with glass and a tumbler to tr and obtain the HYDRATED look that glass from the ocean has.  From what I have read so far the effect I am trying to get is the hydrated gel layer on the beach glass from the breakdown of bods on the surface layer and the addition of water into the glass.  Is this called devitrifying?  Is there a way with a strong alkaline and lots of personal safety equipment that I can obtain this thick hydrated layer that is frosted and crystalline?  I know it has to be an alkaline to obtain what Im looking for.  Can you give me a hand?  Ive spent hours online at night (even on my ipod in bed when I should be sleeping) trying to figure this out. 

All your help would be immensely appreciated!!  Thank you Thank you!!

AAB
USA

What do you think?
« Last Edit: 27/05/2010 04:07:19 by DIVERDOWN »


 

Offline RD

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Re: How can I achieve a hydrated look in glass?
« Reply #1 on: 24/05/2010 03:56:54 »
Quote
One other etching agent was developed and exploited to the full during the 19th century. Known as «white acid», it was made by mixing hydrofluoric acid with an alkali, usually carbonate of soda (washing soda). This produced a «frosting acid» that imparted a dense white frost to the surface of glass. Subsequent etchings with dilute hydrofluoric acid produced a range of satin tones. This process is known in the trade as «French embossing» or «triple embossing» and was frequently employed in combination with brilliant cutting.
www.palaceofglass.com/resources/history/acid.html


If you're not careful with hydrofluoric acid you'll need the assistance of your paramedic colleagues,
 and possibly a seeing-eye dog.

Sandblasting is a marginally safer method to produce frosted glass.

Crackleware is the only decorative crazed glass I can find, and that's produced by physical processes not chemistry.
 

Offline Bored chemist

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Re: How can I achieve a hydrated look in glass?
« Reply #2 on: 24/05/2010 06:52:37 »
I wonder if putting some glass in a rock tumbler with some sand might work.
 

Offline imatfaal

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Re: How can I achieve a hydrated look in glass?
« Reply #3 on: 24/05/2010 12:35:03 »
What do they use for etching the security numbers on car windows - I guess it is pretty nasty stuff, but might be the easiest way.  A carborundum (spelling?) grinding/polishing paste would work but be difficult to get uniform - one of the polishing pastes that I got with my dremel was abrasive yet find enough to mist glass nicely  - Matthew
 

Offline RD

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Re: How can I achieve a hydrated look in glass?
« Reply #4 on: 25/05/2010 06:48:17 »
What do they use for etching the security numbers on car windows - I guess it is pretty nasty stuff,
but might be the easiest way.  A carborundum (spelling?) grinding/polishing paste would work but be difficult to get uniform


There is glass etching paste / cream, but it's chemical not abrasive (check out the warning label)

« Last Edit: 25/05/2010 06:50:59 by RD »
 

Offline daveshorts

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Re: How can I achieve a hydrated look in glass?
« Reply #5 on: 25/05/2010 11:23:59 »
If you mean bits of bottle that your find washed up and looking like pebbles, they are not hydrated but battered by sand and sea. The surface is rough so looks whiteish, you can do this by etching as other people have said, but glass is very hard to etch and many of the products use hydroplouric acid (HF).

Other people in the lab I used to work at used hydrofluoric acid (HF) and the problem is that whilst HF is not a very nasty acid, it will go through your skin and damage bones, to the point of people suggesting an axe as a first aid response to a bad HF burn!

Using something abrasive sounds like a much better idea, apparently a lot is done by sand blasting.
http://en.wikipedia.org/wiki/Glass_etching
 

Offline imatfaal

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Re: How can I achieve a hydrated look in glass?
« Reply #6 on: 25/05/2010 17:53:32 »
I am not sure which is worse, the warning label on that bottle or Dave's description of hydrofluoric acid first aid.  I like my glass transparent - and with the dangers of HF I think I will keep it that way.
 

Offline daveshorts

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Re: How can I achieve a hydrated look in glass?
« Reply #7 on: 25/05/2010 18:07:18 »
Ok so what exactly is the look you are after?
 

Offline imatfaal

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Re: How can I achieve a hydrated look in glass?
« Reply #8 on: 26/05/2010 12:05:43 »
The questioner was asking about hydration of glass and I think we have all fallen into a trap of assuming that this is a misnomer and in fact it is just scratching by sand particles in the sea - and that this could be replicated through acid etching or abrasion.  However a google scholar search shows this might not be the case.  Glass does (over long periods) take in water and hydrate and this can be used to date the glass.  There follows an abstract copied from the web

QUOTE
Glass Hydration: A Method of Dating Glass Objects
WILLIAM A. LANFORD 1
1 Department of Physics, Yale University, New Haven, Connecticut 06520

A new nondestructive method for dating or authenticating man-made glass is proposed, and the initial results of an exploration of the potential of this method are presented. The method is based on a relation between the age of a glass object and the thickness of the layer of hydrated glass on its surface, with the thickness of this hydrated surface layer being measured by means of the 15N nuclear resonance depth profiling technique. A qualitative age scale is established for some common 19th- and 20th-century American glass.

Science 27 May 1977:
Vol. 196. no. 4293, pp. 975 - 976
DOI: 10.1126/science.196.4293.975  UNQUOTE

Whether this weathering is what happens to glass we see on the sea-shore I do not know (I still suspect not).  But there might well be a way to speed this process that does not require etching.  I cannot find any article that has freely available text that may help.  Matthew
 

Offline DIVERDOWN

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Re: How can I achieve a hydrated look in glass?
« Reply #9 on: 27/05/2010 04:04:34 »
Imatfaal is correct- I am not looking for the abrasive texture as much as the hydration- the thickness the water takes on as in the excerpt they cited.  I thought it could potentially be done by somehow releasing sodium and adding hydrogen? Completely unsure- you are the scientists!!  Would love to know if there is a way to do it- and yes Im sure HF acid is nasty- I would never attempt it without a lab, protective equipment and a vent hood.. maybe an axe as well!... [:0]
« Last Edit: 27/05/2010 04:06:27 by DIVERDOWN »
 

Offline Bored chemist

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How can I achieve a hydrated look in glass?
« Reply #10 on: 27/05/2010 07:05:46 »
What does this hydration look like?
 

Offline daveshorts

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How can I achieve a hydrated look in glass?
« Reply #11 on: 27/05/2010 08:21:29 »
Do you have a photo of the effect that you are trying to achieve? I think the hydrated layer that they are talking about is likely to be very subtle and not noticeable without some serious equipment, so unless you are trying to sell modern glass as old glass I wouldn't have thought it was an issue.

If you are trying to get the wet ground glass effect that you get from bits of glass that you find on the beach, which then dry out and go white, that is another matter. You basically want to add something which behaves a bit like water but won't dry off.

You may be able to get the effect with some form of varnish (possibly you would have to dilute it to get it to work).

If I am not talking about the right effect, could you post a photo of the effect you are trying to achieve?
 

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How can I achieve a hydrated look in glass?
« Reply #11 on: 27/05/2010 08:21:29 »

 

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