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I asked the glassers on the email Glass List ([EMAIL PROTECTED]) to settle two questions we've been discussing. Their very helpful answers are pasted into this message below. From Carol at Synergy Glass: 1. Aren't most stained glass windows painted on the outside instead of the inside? NO. 2. Are protective glass or acrylic covers on the outside of stained glass windows very common? A Japanese glass artisan told me protective covers are common in Japanese stained glass windows. NO. Lexan was popular in the 1980s as a vandalism preventative for church windows. There are problems though...it yellows over time and doesn't allow for ventilation and breathability, resulting in rotting problems in the wooden frame. Most stained glass windows these days are installed inside the thermal windows to keep the thermal envelope of the building intact. The thermal units provide protection to the exterior. You may get some people saying they sandwich s.g. BETWEEN the glazing of thermal units. This is a bad idea as it pretty much guarantees the seal with fail over time. The Canadian building code is being modified to eliminate the use of these sandwiched thermal units. Carol From Joe Porcelli, Editor of Glass Craftsman magazine: 1. Many painted windows are fired, which means that once the paint is applied to the window, the painted pieces of glass are placed in a kiln and fired at a high temperature, which fuses the paint to the glass, making it a permanent part of the glass. I've seen painted windows positioned both ways, with the painting on the outside on some, on the inside on others. The determining factor may be weather related or purely aesthetic. 2. The preferred material for protective glazing is called Lexan. It is very common and in many cases required to protect valuable glass works. Joe P. From glasser Ceylin Boyd: > 1. Aren't most stained glass windows painted on the outside instead of > the inside? hm, I'm not quite sure how to answer inside versus outside. when you paint a piece of glass, you typically place your pattern on top of a light box and then place the piece of glass you're painting on top of the pattern. then you paint the piece, let it dry, fire it in a kiln, and then if needed, you apply another layer/s of paint (for additional detail, for instance), let dry, then fire again. when the piece is completed, you lead that piece (or use copper foil) exactly the way that you would any other piece of glass. if by "inside" you mean "face up" then, yes, that's how the pieces are leaded. <g> otherwise, you'd have to do some mirror painting to get the images to appear as you wanted them in the final piece. note, it is possible to put multiple pieces of painted glass together and then lead *that*. there are a number of living and dead artisans who specialize/d in multi-layered stained glass pieces (i.e. tiffany and Robert oddy). in the stained glass windows that you see in cathedrals, the painted side of the glass is pointing towards the inside of the building. in ye olde days, that made lots of sense, since the exteriors of the windows were exposed to the elements (there were no "storm windows" <g>). eventually, the paint *will* wear off a window and it will wear off a *lot* faster if you've got weather pounding against them. most well-fired painted pieces can last for a long time (i.e. several hundred years) if not exposed to weather. the life-time of enamels is much shorter (many of tiffany's pieces are starting to fade already and he made extensive use of enamels in his portraits.) these days, most churches have protective covers on the outsides of the buildings. stained glass panels in other sorts of buildings are installed the exactly same way. > 2. Are protective glass or acrylic covers on the outside of stained > glass windows very common? A Japanese glass artisan told me > protective covers are common in Japanese stained glass windows. covers can be either acrylic or glass depending upon size, price, etc. the problem with acrylic is that it's prone to scratches. in most cases, glass is more durable. these days, from what i can tell, most non-residential buildings in the u.s. (especially in urban areas, where the risk of vandalism is high) have opted for such covers (or would like to have these covers!) for private homes that have stained glass, all bets are off. for instance, when i moved into my house, it had stained glass sidelights that didn't have covers. i added some quickly thereafter. it all just depends --ceilyn From Glasser Cec
Wood:
1. Aren't most stained glass windows painted on the
outside instead of the inside?
Stained glass is mostly not stained, but the color
is part of the glass batch prior to being blown or rolled. There is some
painting, mostly for shading and a 3-D effect, which was usually fired afterward
to fuse it to the glass, although in some cases that step was omitted. If
omitted, the paint is very vulnerable to getting rubbed or scratched off.
However, weathering, wind, etc. or misguided scrubbing and harsh cleaners
can also abrade the fused paint. For that reason, the painted side is
usually mounted toward the inside.
It is possible to protect stained glass by covering
it. Acrylic should NEVER be used. When covering it on the outside -
to protect from weathering or vandalism, one must take care that the cover does
not touch the stained glass, so the stained glass can expand and contract
naturally with the temperature. Also you must leave some airspace around
the edges, into the interior space, so you don't get a buildup of vapor as the
temperature rises. Today it is possible to send the stained glass out to a
professional glass place which will be able to sandwich the glass panel between
regular or thermalpane and then create a vacuum - again to be certain there is
no water that will collect on the inside. You have no doubt seen panes of
failed thermalpane where the condensate is so bad you can't see through the
window, and storm windows which hold the moisture in, and the resultant leakage.
Improper "protection" will result in accelerated decay, so the panel will
need to be restored much sooner that usual. After about 100 years, in well
made panels, some restoration is to be expected - mostly the result of gravity.
- Cec
----- Original Message ----- From: "Andrew James" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Monday, August 04, 2003 9:38 AM Subject: RE: Rod Gnomon Hole Placement > John Carmichael wrote (04 August 2003 17:27) > > <What about attaching the gnomon to the building and have it hang > outside of the protective cover?> > > I guess that as far as laying out the dial goes that would be equivalent > to displacing the gnomon away from the dial by > > (thickness of cover) * (refractive index of cover - 1). > > Would anyone like to confirm that or give the correct answer if not? > > Regards > Andrew James > > - > |
