Here is one last bit of info that may help those who are interested in
making a porcelain sundial.  I just remembered that I had this document.

To see photos and read about how I made the porcelain faces for my cupola
sundial, go to pages 14 - 16 in this PDF doc.  It also shows how I attached
the gnomons and how I made the round face bezels (frames), and how you would
attach the sundial assembly to a wall (or a cupola as in this case.)  I used
14 gauge copper sheet for the gnomons and bezels, and 12 gauge carbonized
steel sheet for the face.  But if you want a colored gnomon and bezel, you
could use powder coated steel for the gnomon and/or bezel. Most porcelain
manufacturers apply the porcelain to objects or sheets made of carbon steel.
But some apply it to aluminum or treated stainless steel. Note that they
must cut out the gnomon attachment holes BEFORE the porcelain is applied!

See:

http://www.advanceassociates.com/Sundials/Stained_Glass/CupolaSundial/Sundia
l_Cupola_Assembly_Instructions.pdf


-----Original Message-----
From: Frank King [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, April 25, 2007 2:34 AM
To: John Carmichael
Cc: [EMAIL PROTECTED]
Subject: Re: Porcelain Sundials

Dear John,

I write off-list this time, mostly because the list
has heard rather a lot from me recently!!

Your correspondence has been fascinating.  It has
taken a while to sort out the different techniques.
One reason is that U.S. terminology and English
terminologies are a little different.

As John Davis has mentioned to me: in England, we
think of "porcelain" as referring to tea cups and
high-voltage insulators, sometimes also to ornaments
made in Germany and elsewhere.

To English ears, the term "porcelain dial" sounds
as though it is made of ceramic, perhaps made up
from tiles.

The term "powder coating" is also new to me and I
have been trying to find terminology which would be
well understood to English manufacturers.  I think
the word "enamel" would be used for both kinds of
technology. 

I am starting to settle on the two terms:

  1. high-temperature vitreous enameling

  2. low-temperature oven-baked enameling

The first is definitely the more exciting and more
durable but limited in size.

The second is obviously much cheaper and you can bake
a whole car if you want to!

I was most interested in your detailed explanations
and, especially, that with oven-baked enameling one
is limited to two colours.  This might explain why
most clock dials are just one or two colours in
England.  The main colour is usually blue but I
attach a photograph showing a church clock with a
red dial.

This is S. Mary's Church, Penzance which is the most
southerly and most westerly Town of England which is
why you can see a Palm Tree in the foreground.

I send this to you not just because of the red dial
but because, just to the left of the dial, you can
see the top of a pole carrying power lines.  You
can clearly see the white insulators (one of these
is very close to the X for 10 o'clock).  This white
insulator is made of what we call porcelain!

You can see why the idea of a porcelain dial is a
little confusing to English diallists!!!

By the way, the X and the other Roman numerals are
almost certainly gold leaf.

Best wishes

Frank



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