The good people at Glassrobots asked if I would share my thoughts on new trends in glass and matching opportunities with tempering technology. They asked, probably because firstly Glassrobots was our choice for providing our second tempering furnace to be delivered in December 2004, and secondly because we have a similar objective for providing quality and service.

Since making the commitment to Glassrobots, we have worked closely to assure that this new furnace proves to be one of the most technically advanced in the world. With the relationship we have since developed, I was proud to accept.

My company, Craftsman Fabricated Glass Ltd. of Houston, Texas, is a full service fabricator. Years ago we chose to focus on providing excellent representation and technical support for customers, plus quality benefits for our deserving employees. Too often though, we compete with fabricators who provide little benefits, and it shows up in their pricing. To get the modest premium that we need in these instances, it is important that we spend time selling customers on our commitment to furnishing superior quality, service, and innovative products. For this reason, we are constantly searching for ways to differentiate ourselves from those cheaper fabricators.

Regarding trends

Rapidly escalating energy costs are going to drive the single most exciting trend I see in glass. For every country with a big appetite for imported energy, it is easy to conclude that energy efficient glazing will offer a considerable energy-saving solution. Think about what is budgeted for the future plus what has been spent the last few years: primary glass manufacturers will have invested over a billion dollars on developing glass and coatings that provide great comfort and reduce demand for expensive interior conditioning.

The most significant of those are high light-transmission, high performance solar control Low-E glasses that can be cut and tempered after coating. The bonus for using solar control Low-E glass is the comfort people experience in close proximity to the glass. For example, occupying formerly “warm, uncomfortable” rooms or offices with westerly facing glass elevations will now be significantly more comfortable, and for building owners, easier to lease.

There is also a lot of interest in bringing natural light into a building. It saves energy, and it provides a brighter, happier environment. The inherent difficulty with clear glass is with privacy… besides the obvious reason, not everyone wants to be a focal point or have others see who they are meeting with. Patterned glass is the solution, but until recently, choices were limited to some boring inexpensive thin glass patterns, or very expensive cast glass.

Now there are exotic new patterns being created that are priced more competitively; some of those are created with deep impressions in one surface of the glass in thicknesses up to 1/2” (12mm) for use in glass wall systems. Those deep impressions create a problem during the tempering process because the added surface area will exaggerate heat absorption for one surface of the glass.

Matching up support equipment

Five years ago, my company invested in convection technology. After doing our research, but prior to purchasing the furnace, we were able to determine the following:

Tempering deep impression patterned glass and new higher performance coated glasses can be too challenging for old technology furnaces. High performance Low-e glass is most difficult because the coating does a great job of blocking heat. While the coated glass surface is slow to heat-up in radiant furnaces, the uncoated surface takes in heat too quickly… by the time the coated glass surface gets to the prescribed exit temperature, the glass already looks like an oil-canned washboard.

A few innovative thinkers were beginning to realize that elements radiating energy towards the coated glass from a distance is not very effective, and doing something about it. Two technologies were being developed: one used compressed air vented into the furnace, another was recycling convection air. Convection heating technology is what got my attention. The concept was to recycle hot air from within the furnace, through heating elements in ductwork and redirected within inches towards the glass surface… it is substantially more effective than simple radiation.

To control the top and bottom pressure inside the furnace, variable speed fans are used to control air pressure. Superior flatness is initially achieved by increasing pressure towards the coated surface while lowering the pressure at the bottom surface to stabilize heat absorption before quenching. Just the opposite recipe is needed for deep impression pattern glass. Oversize glass and heavy glass benefit from these same control mechanisms.

The most common objection in heavy tempered glass is the center scuff (heat streak down the center of a lite); this is caused by the glass edges bowing up from too much bottom heat, and then riding the rollers with the weight of the glass on the center. Convection technology has proved to be a solution for this problem, too.

On making the first Convection Furnace decision

We purchased our first convection furnace five years ago. We had never tempered before, so this was a big decision for us. At that time, convection was considered a big gamble; lots of moving parts and the cost was ~50% more than a radiant furnace. But we believed in the technology, and our customers have proved that choice to be right. When a customer is faced with a quality product or a visually unsatisfactory product … quality wins every time.

For comparison purposes, I have included a photograph of a coated glass installation that demonstrates what a radiant furnace produced, and during the same period, a photograph of a glass Job with high performance PPG Solarban 80 coated glass that Craftsman heat treated on its convection furnace (Craftsman is a PPG Certified Fabricator). The results are dramatically different. Although both jobs meet current federal quality standards, architects and building owners will soon learn there is a choice… it is no longer necessary to accept exceptionally poor visual quality glass.

About the second Convection Furnace

Besides producing higher quality, we confirmed that a convection furnace’s cycle times are substantially faster. Despite having extra cycles and making modifications to further improve efficiency, we continued to be sold out of capacity for two years; it was time for our second line.

When you are sold out of capacity, it can be unnerving to be down for even a few hours. We learned quite a lot about the strengths and weaknesses of our furnace over the last five years. We were determined to fix those weaknesses and improve on the strengths.

Convection technology has advanced quite a lot since. We wanted to collaborate with a furnace manufacturer that believed in convection - without bringing outside air into the furnace, who used the latest of control technology, and flexible enough to build on our own expertise and experience. We found this in the people at Glassrobots, so we committed to purchasing a double bay Glassrobots RoboTemp™ Multiconvection Flat Tempering Machine earlier this year. We are a team; the goal is simple… all are focused on Craftsman receiving the most technically advanced tempering furnace that reaches well beyond “acceptable” specifications for tempering: it will be very reliable, very efficient, and produce the highest of quality that others will be measured by.

The second part of this equation is trust and communication. We find that Glassrobots is doing a substantial amount of research and development that parallels the expectations and trust we placed in them when we made our choice. Communications have been excellent. There has been considerable coordination with the manufacturers of our Ashton seaming, edge deletion and washing machine line that feeds the furnace, and the LiteSentry quality assurance measuring device at the exit end of the furnace. For these reasons, I am confident with our decision and I find no reason to be nervous about the installation and start-up.

Bob Lawrence

President

Craftsman Fabricated Glass, Ltd.

Houston, Texas USA

Bob Lawrence has been a part of the glass industry for over 35 years, beginning his career in 1968 while attending University of Texas El Paso. He is the owner of Craftsman Fabricated Glass, Ltd., which manufactures and distributes commercial and residential products such as tempered and insulated glass, framed and frameless glass entran-ces, bath enclosures, and so forth for its glass shop customers. The company fields a strong management team with excellent employees; all 220 of those employees remain focused on Craftsman earning and keeping a leadership position in the fabrication market.

Acknowledging his remarkable career, the National Glass Association awarded Bob with its most prestigious honor as 2002 Glass Professional of the Year. This award is presented annually to an individual who exemplifies outstanding service to the glass industry.