Volume 44, Issue 6 - June 2009
Everything I Learned About Glass …
A fresh batch of faces learned the basics of the fabrication and glazing industry during the Glass Association of North America’s (GANA) annual Glass Fabrication and Glazing Educational Conference, which took place this year April 6-8 in Cincinnati. The conference is geared toward individuals with five or fewer years in the industry as it provides an educational foundation in a number of essential areas. For those of you who didn’t make it yourself, we have a few of the essentials here for you. And if you’re not new to the industry yourself, we’re sure you’re eager to pass on your knowledge about glass to someone who is; be sure to pass along the following tips and information as well.
Oh So Trendy Glass
1. McCann said that “much larger sizes” than previously used are becoming the norm. In conjunction with that, comes thicker glass and a move to low-iron, McCann pointed out. As lites become larger in area, an increase in thickness is necessary to prevent bending. With thicker glass may come a deepening of the green tint caused by iron content, leading to further requests for low-iron glass.
2. In addition to bigger, heavier glass, McCann said glass is being specified for multiple applications. For example, you might find on your next job a request for a high-performance coating on a glass that also must be impact-resistant and fabricated into a thermally efficient insulating glass (IG) unit to boot.
3. McCann also addressed the growing demand for energy-efficient glass. New generations of glass coatings will further help designers let light in while keeping heat out. While double silver low-E coatings are popular now, McCann said, he predicts that triple silver coatings will become more prevalent.
Cutting and Edging Correctly
2. Use a sharper wheel angle for thin glass and blunter angle for thicker glass.
3. Beatty said people often ask him how long cutting wheels last. It’s different for different things, he said, but he tells people: “These carbide cutting wheels are not very expensive … compared to the cost of the glass. If an operator waits until the glass breaks to change the wheel, he wouldn’t work for me.”
Glass Tempering Systems for the 21st Century
1.There are three types of tempering furnaces: radiation, convection and conduction. Radiation involves heating with electromagnetic waves from the furnace heating elements. This once-preferred method is not used as commonly as in the past since newer low-E coatings are designed to reflect that heat away from the glass. Convection heating is where hot air is blown onto the glass; and conduction involves bringing the glass into direct contact with a hot material, typically ceramic rollers.
2. Cocagne said he believes that a large portion of future glasses will have high performance coatings and many will be coated on both the top and bottom. There also will be a push for processing more ultra-clear glass, larger lites and increasingly thinner glass. “Furnaces of the future will need to be able to accommodate all of these demands,” he said.
3. Cocagne said we can expect to see tempering systems include short cycles of convection heating, as the market will be driven by high production volume with low operational energy consumption; a move toward hollow rollers, which can help minimize conduction heating effects and provide control for convection heating from the bottom; and “smart” control systems for bed loading, furnace heat control and quality control.
Passing the Test
1. Testing a mock-up in a lab or in the field can help to uncover design issues and installation problems, Livermore said. “They establish a benchmark of performance and installation expectations,” he added.
2. Before testing, define the area of the mock-up to be tested, whether it’s a run-of-the-mill portion or the most complex part of the project, a flat wall or a corner, etc. Each party in the process needs to be involved in the decision-making process, he said, which needs to clearly identify responsibility for different wall types. During the testing is when the contractor should start to establish a benchmark of quality they’re looking for in the field.
3. During the test itself, Livermore said, “It would be a good idea to have everyone involved survey the test chamber.” If something isn’t adequate, it’s better to point that out before the unit fails the test. In addition, he stressed the importance of remembering to go back to the mock-up drawing to note changes that take place once the set-up or testing process has gotten underway. “This is critical,” he said. The owner and test lab also need to be notified of any deviations from the original mock-up design. Livermore added, “Everything we do on the test we’ve got to carry through on the drawings and in the field—so the last thing we want to do is a band-aid fix.”
Know About Mirror Before It Reaches the Wall
1. When it comes to fabrication, Walker said, keep your work area clean, since grit and dirt can hurt the mirror’s front and backing. Wearing gloves and vacuuming the cutting table area were some of the suggestions he offered. For grinding and polishing operations, he stressed the importance of using clean, fresh water and an appropriate coolant as a lubricant. “pH is important. It can mess up your mirror, and it can mess up your machine,” he noted, adding, “Machine set-up is so important.”
2. “Please do not use silicone … use mastics,” Walker said, adding, “I’ve seen people send the mirror back and say the mirror was bad when the mirror was the only good part. It was the silicone.”
3. He also reminded the audience not to use ammonia cleaners that can remove the copper layer if applied on the mirror’s edge. “Then all you’re left with is silver and it’s just like the silver in your home: it tarnishes,” he said. “I cannot stress enough to leave that copper alone and that means don’t put stuff on it.”
Ensuring Quality Laminated Glass
1. Storage and handling PVB is an important aspect of ensuring a quality laminated product. Storing the material in a way that maintains the packaging integrity will help keep out moisture and contamination. PVB, LaPorte said, has sponge-like characteristics and it will suck up water. It also is an adhesive and will stick to itself if not stored properly. “So store the PVB in a temperature between 40 to 50 degrees Fahrenheit,” Laporte said.
2. Cutting, cleaning and preparing the glass for lamination also is important. Make sure the glass cutting equipment is in good working conditions so that lites are cut neat and evenly; change the glass-washing tank regularly and use a water washing temperature of between 120 and 140 degrees Fahrenheit. Dry the glass thoroughly and uniformly.
3. A proper clean room environment is critical in assembling glass. “The room has to be ultra-clean,” Laporte stressed. If it’s not, the PVB will pick up contaminants [that will end up as part of the glass].” Laporte suggested having double entry doors leading to the clean room to ensure the factory floor environment is not brought in and using tacky mats to prevent dirt from being not brought in on shoes.
Third-Party Inspection of Glass Fabrication and Installation
1. Third-party objectives can include assistance in ensuring code and construction document compliance; backstopping vagueness in codes and construction documents; and verifying proper coordination between glass manufacturers and curtainwall contractors.
2. Why might a third-party inspector be brought onto a project? Sometimes it’s mandated by code and other time it’s requested by the owner or client. In other cases it could be requested by the architect/engineer.
3. Third-party inspectors also can help verify quality and consistency of the glass products. Inspection methodologies vary from job to job, although a raw material inspection is often used for flat glass. “Third-party inspectors can help the project team through the construction phase … and understanding quality control obligations,” Berger said.
When Insulating Glass Units Fail
1. For starters, he advised attendees that in conducting their own investigations they make their goal trying to prove what they believe is not true, so as to not run the risk of coming to conclusions based on assumptions.
2. In an investigation, Lingnell advised checking for information on glass performance, such as replacement records and evidence of seal failures or breakage; reviewing maintenance schedules; studying plans and specifications; and checking with the installer and fabricator for additional background if needed.
3. The next step in the investigation should be to ask: “What’s different?” By looking for factors that could have changed the system in some way, for example, the investigator can determine what may have led to the failure.
Megan Headley is editor and Debra Levy is publisher of USGlass magazine.