Wednesday, February 2, 2011

Too Big For Its Britches

Today marked the completion of a two-day on-site restoration of a large residential stained glass window in New Brighton, MN, featuring a hand-painted castle scene in its center.  The window is only about 15 years old but because it was originally fabricated with insufficient structural support, the bottom border was already folding in on itself and the lower floral areas were beginning to bow.   

In consulting with the client, I came up with a plan that would ensure he would not have to deal with this window again during his lifetime.  The window was removed and carried to a lower level garage where folds and bulges were flattened out through a combination of heat and careful hand manipulation.  Next, broken glass pieces were matched and replaced, followed by the creation of a steel support grid compromised of interlocking vertical and horizontal brace bars, which was then soldered onto the outside of the stained glass.

Typically, brace bars are applied to the inside of stained glass windows but since there was enough clearance between the stained glass and the insulated glass unit behind it, I was able to hide a fairly extensive amount of steel, providing a much more attractive interior view.  After this, the old brace bars (two small 3/8" steel horizontal supports!) were removed from the inside of the panel, solder joints smoothed out and darkened to match the old, then the window was reinstalled. 

This window, nearly 6' x 5', is a perfect example of why you should never create a panel that exceeds the 4' x 4' maximum panel size rule of thumb. When you get past four feet in both directions,  a new dynamic occurs in the center of the panel that is very difficult to manage with standard horizontal bracing alone.  You almost always have to incorporate vertical as well.  

Some of you non-industry people may be saying, "But church windows are way bigger than 4' x 4' and they're just fine?"  The trick here is that the design may look continuous but the window is almost always broken up into smaller panels that are either stacked on top of one another using slip joints or divided by steel or iron t-bars anchored into the wood frame to help distribute the weight.  Rarely will you see a window this big fabricated in one piece and if you do, you will hopefully find that someone has reinforced the hell out of it.  If not, um... you might want to step back a bit.  

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