Volume 38, Issue 10, October 2003
Tools of the Trade
Technical Tools for Insulating Glass Fabricators
by Jason Ackerman
Insulating glass (IG) technical tools are a critical element in ensuring IG unit quality. Fabricators should consider adding a variety of tools to their quality assurance arsenals, including some or all of the following.
TDS Tester 1: Glass exiting the glass washer is dried two ways. First, it is dried mechanically via air knives in the washer unit; then the thin layer of remaining moisture evaporates. If the final washing rinse contains hard water, a thin layer of minerals (consisting mostly of magnesium and calcium) is left behind. IG sealants are formulated to produce a strong, weather-resistant bond to clean, dry glass. Therefore, a hard water deposit can impair the bond between the glass and sealant. To eliminate this problem, the rinse water must be evaluated continually.
For this reason, I carry a total dissolved solid (TDS) tester to test the water quickly. If hard water is contained to 200 parts per million (ppm) or less of dissolved solids, there is generally no concern. But if the water tests any higher then 200 ppm, it should be treated to remove these hard ions, by installing either a deionizer or by reverse osmosis. A water softener alone does take out the hard ions. However, it simply replaces them with a layer of sodium ions, and sodium can also impair bond development due to its greater solubility.
Glass Jar: IG and glazing sealants do not stick reliably to detergent-laden surfaces. A very slight detergent contamination may not cause a loss of adhesion in the short term, but it will reduce the life of an IG unit in the long term. Glass contamination occurs when an excessive amount of detergent is used or when equipment is used improperly or malfunctions. To test your water, fabricate an IG unit with an open corner or hole. Next, pour some de-ionized water into the unit and slosh it within the unit completely. Pour the water into a glass jar and shake it. Compare this jar to a jar of clean water. If the glass is clean, the water should not produce froth when shaken.
Infrared Thermometer: Most IG systems depend on heat for a properly fabricated unit. For a quick and accurate measurement of surface temperature, use an infrared thermometer. Its use can vary from measuring the temperature of IG exiting the press to measuring the wash-water temperature in the glass washer.
Caliper: IG manufacturers are constantly measuring precise components throughout the day. The tool that gets the most use in my bag is an electronic digital caliper. This tool provides a very accurate reading to +/- .001 inches or +/- .01 millimeters. The caliper is critical when measuring the width of a glazing pocket and matching it up with the overall thickness of IG. It can also measure glass thickness
Argon Concentration Measurement Service: traditionally, measuring argon concentration in an IG unit requires destructive analysis by piercing the bond line of a spacer. However, a new technology provides the first non-destructive technique that accurately measures argon concentration to +/- 2 percent. This device currently detects only argon and works by generating a high-frequency, high-voltage, low-current spark that creates plasma within the unit. The atomic emission of the plasma is then measured. The spark color of the emission varies with different argon concentrations, providing an accurate IG unit argon concentration. This is a quick and easy way to determine argon fill percentages.
Measuring Magnifier: There is a direct relationship between glass edge quality and breakage. If glass breakage or stress cracks occur, a good starting point is to look, literally, more closely at the score and glass edge after cutting. Too often, scores intersecting at “T-junctions” will put a nick on the glass edge from which a crack will grow. Correct cutting wheel pressure will result in hackle that is less than 10 percent of glass thickness. The measuring magnifier is used to clearly see score intersections and precisely measure hackle depth.
Jason Ackerman is a sales technician for TruSeal Technologies Inc., based in Beachwood, Ohio.
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