Subject: Re: Sheetmetal and Glass

From: Mogollon <[email-masked]>
Date: Wed, 15 Feb 95 22:51:42 -0500

Marc Horton <[email-masked]> writes:
 
>I am interested in creating a peice that involves attaching half of a 
>glass bottle to sheet metal. Before I do this I need to determine the 
>best way to attach the bottle to the metal.
>
>ALSO I would like to know:
>
>	-What is the melting point of glass (will it succumb to a torch?)
>
>	-What is the best way to colour metal?
 
Try epoxy.
 
You can melt glass with a cigarette lighter.
 
Taint or powder coati.
rs

---

From: [email-masked] (Douglas Wiggins)
Date: Sat, 18 Feb 1995 23:50:00 GMT

>best way to attach the bottle to the metal.

I picked this up as a reply to a reply, but luckily someone left
your name in the message (thank you).

How do you need to attach the glass - does it need to be a purely
glass-to-metal seal, or can adhesives be used? If the latter, it is
easy to glue glass to metal with any of several adhesives - I like
the polystyrene adhesive which can be purchased under the names of
E6000, also sold by Goop company under another name. Barge cement
is another strong adhesive, but not clear. Sun-Set is an
ultraviolet setting adhesive which provides a glass-clear bond, but
this is intended for producing invisible bonds from glass to glass;
I don't know how strong it is for general bonding.

If you need to fuse glass to metal, it will depend upon the glass
and the metal as to whether it will work - it is necessary to match
the coefficient of expansion or they will just break apart when
cooling. Most glass will NOT fuse with most metals, but there are
many special glasses which are intended for making something called
a "graded seal", which means that the target glass is joined to a
glass with a slightly different COE, which is joined to yet another
glass with a COE closer to that of the metal, and then to another
and another until, finally, the glass being joined has a COE that
is close enough to the metal that it can be fused directly to it.
The coefficient of expansion of ordinary window and bottle glass
(soda-lime) is about 86 x 10^-7 cm/cm/degree C (starting at 300C).
The COE of Pyrex-type glass (borosilicate) is about 33. In case you
wonder what the numbers mean, it means that glass will expand by,
say, 86 x 10^-7 cm for each cm of length when raised by one degree
Celsius (it doesn't seem like much, but for window-type glass, a
difference of as little as three can result in fractures, but with
Pyrex-type glass, a difference of up to ten can be used, but that
would be pushing it). It is absolutely necessary to know what the
metal is that is being joined, before any work can begin.

 >    -What is the best way to colour metal?

The melting point of glass depends on the kind of glass - window
glass begins to soften at about 950 F, while Pyrex-type glass does
not begin to move until it reaches at least 1100 to 1130 F. The
thickness of the glass will also be a determining factor - you had
a response saying that glass would melt with a cigarette lighter,
and it will, if it is thin enough; 1mm "stringer", thin glass rods
used to decorate glass in fusing art, can be shaped in the heat of
a candle flame - one artist makes little icons of animals and such
to sprinkle over her fused art by using a candle flame. However,
oxy-propane is the preferred flame for working glass (air-propane,
or even air-alcohol, can be used to work soft glass, which is
another term for soda-lime or window glass).

As for coloring metal - this is not my field, but I know a tiny bit
about it. In my opinion, it is best to color metal by changing the
color of the metal, itself (rather than by painting it). There are
several books on the subject; "The Art of Patinas" and "The
Coloring, Bronzing and Patinization of Metals" are two that come to
mind. These processes involve oxidizing or chemically reacting the
surface of the metal to make it change color - usually, this also
protects the metal from further reaction to the elements. If you
wish to obtain some references on this subject, I can recommend:

Craft Books
4 Maple Street
Chester, CT 06412
(203) 526-9887

They have, at least, the book on Coloring, Bronzing and Patination.

Good luck.

  -Douglas Wiggins [email-masked], Portland, Oregon
---
 * OLX 2.1 TD * Zoron Research, Inc. - Custom Glassblowing to spec