Tool hound: Heat-treated glass detectors

December 4, 2008


“EDTM's SG2700 is the first new heat-treated glass detector to come on the market in some time. While there may be others available, the SG2700 has some very user friendly features. Its compact size makes it easy to transport and to use in the field. The meter allows you to test single lites, as well as insulating glass units. It also allows you to test the glass from either inside the building or outside. Some of the other detectors in the market place require you to be able to access the glass edge, which normally isn't possible once the glass has been installed. Of lesser importance but still a benefit, the SG2700 allows you to determine the glass thickness of the lite it is in direct contact with.
Having this type of tool is important when we are asked to go out into the field to check installed glass to confirm that it has been heat-treated. It is nice to have an instrument that allows you to clearly demonstrate to your customer, or a home owner that the glass has been heat-treated.”
—John Colapietro, quality manager, Oldcastle Glass, Santa Monica, Calif.

Description: The SG2700 identifies strengthened, or toughened glass—heat-strengthened glass, tempered glass and safety glass. The user simply slides the meter across the glass and watches the surface reflections from each piece of glass appear on the specialized display. Not only can the user tell if the glass has been strengthened—they can also estimate the thickness of the first piece of glass in the window. You effectively have two2 products in one. The SG2700 can test single panes of glass as well as windows with multiple panes of glass, all from a single side.

Suggested uses: In glass processing or window assembly plants, SG2700 provides a great tool for confirming stacks of glass. If crates are unmarked, the SG2700 can offer a quick test to confirm the glass is strengthened. In the field, the instrument can be used to confirm that a window contains strengthened glass, and is particularly important when the tempered stamp on the window is missing or hidden behind the window jam. After-market, window companies doing replacement work can use the tool to confirm they reorder the correct product. Window film companies can use the tool to determine whether they are working on strengthened glass, as it could impact the type of film they select for the project. IG repair companies that fix windows with seal failures can confirm if a window contains tempered glass—if the window has been tempered, they cannot drill holes into the glass. Building inspectors and architects can use the SG2700 product as a simple method to spot-check windows on a job site.

Importance: With limited ways to test tempered glass, this relatively inexpensive product allows you to confirm that glass has been strengthened. The alternative destructive test of breaking the glass is not always an appealing option, especially when the finished product has already been installed. With safety issues always a major concern for the construction industry, it is great to have a simple tool to provide you piece of mind. 

Power source requirements: 9 volt alkaline battery

Weight: Less than 1 pound

Accessories: Carrying case with a belt loop and an extra pouch to carry the operating instructions; light blocking cloth to use during extreme daylight.

Warranty:  One year

Price: $349 each. Volume discounts available.

Available from: EDTM Inc., 745 Capital Commons Dr., Toledo, OH 43615, 419/861-1030,,, and through distribution partner C.R. Laurence Co., 2503 E. Vernon Ave., Los Angeles, CA 90058-1897,

Merlin TGI

"I use the Merlin TGI because it is the only portable product on the market to test for the presence of toughened glass, and it fits easily into my pocket. The Merlin TGI helps to ensure that I have like for like glass in replacement units. Older glass units were not always marked, and some of the ones that were, the markings were hidden within the frame, making the TGI an essential tool for the accurate replacement of glazing."
—Richard Parham, owner, Parham Brothers, United Kingdom

Description: The Merlin TGI indicates whether or not glass has been toughened, quickly, easily and from one side only, and works with double-glazed units.

Suggested uses: The Merlin TGI is made for the non-destructive indication whether or not glass has been toughened. Users include glaziers, building surveyors, inspectors and architects.

Importance: It allows a non-destructive indication whether or not glass has been toughened.

Power source: Rechargeable battery

Weight: 0.24 pounds

Accessories: Leather pouch, battery charger

Warranty:  One ear

Price: $ 307.17

Available from: Bohle America Inc., 13850 Ballantyne Corporate Place Suite 500, Charlotte, NC 28277,,