As the old adage states, “An educated consumer is the best consumer.” With this in mind, I’d like to take some time to help you understand what to look for when shopping for quality stained glass artwork. If you’re not familiar with how to judge the quality of stained glass art, then please take a few minutes to read the following on how to tell the difference between quality handcrafted stained glass artwork and stained glass made by amateur crafters or on the assembly line of a high-volume window manufacturer. Hopefully reading through this brief synopsis can save you from another old adage; “Buyer beware.”
Design & Craftsmanship
With the ease of shopping and selling over the Internet there are many people out there producing stained glass, but be careful in choosing between an amateur crafter and someone who is a professional craftsman. Before choosing a studio or artist there are two important things to look out for, poor design and poor craftsmanship. Many crafters use the same old tired designs picked out of a book at the local crafts store. This design is quickly pieced together with sloppy craftsmanship. When shopping for quality stained glass, be careful to look for an artist capable of innovative, original design and clean, precise craftsmanship.
Precision is the most important aspect of stained glass construction. A quality stained glass piece consists of properly sized and cut pieces of glass with clean lead lines and smooth soldering. A poorly crafted piece that has improperly cut glass leads to sloppy leadwork and soldering. There may be gaps in the lead lines and many of the glass panes may even move within the lead. From a distance these structural problems may not be evident but they will lead to problems down the road. A carefully crafted stained glass piece should last for decades without showing wear, while hastily assembled pieces will begin to sag and separate within a few years.
Avoid pieces with sharp interior angles on a single piece of glass. A sharp interior angle is impossible to cut by hand since glass breaks on a straight line. This type of cut indicates that a glass bandsaw has been used. Forcing this shape into a design weakens the piece and it will inevitably break.
Copper Foiled Stained Glass
On copper foiled stained glass, each piece of glass should be surrounded in copper foil and there should be no visible ends to the copper foil, the ends should slightly overlap near the corner on each piece of glass. All of the copper should be thoroughly covered with a bead of solder. Make sure all of the solder lines are smooth. There should be a minimal amount of lumps and no evidence of “popped bubbles”.
The solder lines should show a uniformity of width throughout the piece. Although the artist may choose to vary the width of the solder lines for artistic effect, too much variation could be a sign of poor craftsmanship. Look closely at the lines and shapes. Straight lines should be perfectly straight and curves should curve smoothly.
The patina on the solder lines should have a uniform appearance. A blotchy or uneven look indicates that the piece was poorly cleaned prior to the application of the patina or has been exposed to the elements.
Any finished piece should ideally be framed in wood or with a zinc channel. If the piece is small or unusually shaped, the edges should be covered with a thick bead of solder.
Leaded Stained Glass
With leaded stained glass a channel of lead is used to securely hold the glass in place. This is considered more difficult since it requires more skill and precision than foiling because each piece of glass and lead must be precisely fitted together before they are soldered. Most foiled panels are fitted together with the use of a grinder to minimally shape each piece. However, because a grinder is used, the copper foil method (or the Tiffany method as it is also known) has become the preferred method of hobbyists. A poor glass cutter can unfortunately substitute a grinder for experience when doing copper foil.
Leading requires very precise glass cutting since the lead channel follows the contour of the glass exactly. Although most modern studios have a grinder, most pieces in a leaded window can be fitted together with little or no adjustment, and infrequent use of a grinder, if they have been cut by a good glass cutter. The lines of the lead channel should be smooth, with the straight lines being perfectly straight and the curves being smooth.
Lead requires soldering where one piece of lead touches another. These solder joints should be smooth and relatively small without globs or long trailing arms of solder.
The intersection of lead lines should be even and match in all directions. Cross intersections should not be staggered. Angle joints should transition smoothly from one lead channel to the next.
If patina is applied to the lead channel, it should be even and without blotches. If it is done the old fashioned way, with brushing and elbow grease, the lead should have anything from a dull pewter finish to a black finish, and the finish should be fairly even.
Putty should be applied to every piece made with lead, as it helps give the window “good posture” because of the support it gives to the glass. Most companies make their own putty and although the ingredients vary. It is recommended to avoid any piece that utilizes Portland cement in their putty matrix. It hardens too well, and does not adequately cushion the glass. Secondly, it’s nearly impossible to repair a piece puttied with Portland cement. Each region of the US tends to refer to putty as something different. The terms mud, putty, and cement seem to be the most common, even though cement is really a misnomer because no true cement should ever be an ingredient in putty.
Putty is also applied to a leaded piece as weatherproofing. When correctly applied, putty is watertight for many decades. The putty should be applied evenly under each and every lead, on both sides of the window, and the excess is typically removed. Although some studios leave extra putty on church windows and windows that are installed at great heights (where it’s not really noticeable), it is advised to avoid excess putty on residential pieces. Putty can be used to cover up deficiencies in glass cutting which can lead to structural problems in the years to come.
If the piece has a painted design or lettering directly on the glass, ask the studio how they affix these images to the glass. If the paint is not properly affixed or inferior paint is used, it may come off with the use of glass cleaner or other cleansers. A quality studio will only use specially formulated paints or traditional glass paints, which get fired into the glass at temperatures over 1000-degrees Fahrenheit.