[TheForge] Jewelry Finishes

Tue Nov 19 10:58:00 2002

For you guys interested in glass on steel, Thompson Enamel in Bellvue, KY are THE GUYS!! They are the experts on glass on copper, on carbon steel, stainless steel, silver, etc. etc.

They make the ground glass products tailored to the metal backing desired. 
You can also do glass on glass, a neeeeeeat thing to play with in the kiln.
Ray Miller
Cincinnati
> 
> From: "Bruce Freeman" <[email protected]>
> Date: 2002/11/19 Tue AM 08:58:31 EST
> To: <[email protected]>
> Subject: Re: [TheForge] Jewelry Finishes
> 
> John,
> 
> The process is called "enameling" and there's a whole (jewelry) art to it.  When enameling on copper, the problem with the glass breaking off is minimal.  It is certainly possible to enamel on steel, but I don't know the details.  Ideally you match the thermal coefficient of expansion of the glass to that of the metal, then cool slowly enough that they don't break apart anyway.
> 
> The simplest would probably be to buy commercial glass frit intended for use as enamel on steel.  I can look up catalogs for you if you want, or just google-search the subject:
> 
> +glass +enamel steel 
> 
> maybe?
> 
> There is a test for compatability of glasses that might be applicable to metals.  For glass, you heat and soften two rods of glass, fuse them side-by-side while hot, then draw them out to a "wire".  Let it cool.  If the "wire" stays straight, the glasses are completely compatable.  If it bends or curls, they have different thermal coefficients of expansion.  The greater the bend the worse the match.
> 
> Conceivably you could use thin steel sheet and enamel one surface.  AS IT COOLS, observe whether it tends to bend.  If so, the glass and metal are not compatable.  However, be aware that thin metal is a bitch to enamel.  Thick metal is always better.  So even if the glass and metal are compatable, the glass could spall off the thin sheet when it gets cool.  The reason is probably mostly stress due to too-rapid cooling.  
> 
> As you say, slow annealing is always better for glass.  Typically this is done by placing the piece in a furnace at the appropriate temperature (which depends upon the glass, but may be as low as 800 F) and then turning off the furnace and allowing it to cool naturally.
> 
> Bruce
> 
> Bruce
> 
> _______________________________________________
> http://mailman.qth.net/mailman/listinfo/theforge
> theforge mail list group photo site is
> http://www.photoaccess.com
> Login:  [email protected]
> password:  anvil
> ___________
> 
> 
> 