GANA's Glass Fab Covers Tips for Handling Glass
May 4, 2011T
by Megan Headley
The Glass Association of North America's (GANA) Glass Fabrication Educational Event continued today in Kansas City, Mo., with more tips on handling glass through cutting, washing and other processes.
|GANA's Glass Fab conference took place yesterday and today in Kansas City, Mo.|
Chuck Beatty of Edgeworks opened his presentation on “Principles and Fundamentals of Glass Cutting” with an explanation of cutting glass as overcoming the compressive stresses on the surface. As Beatty explained, cutting glass means trying to separate the surface without destroying it. “In the glass cutting process the first rule would be never, ever destroy the surface of the glass," he said.
Beatty went on to break down how to release the tension within the glass in a controlled fashion. He offered his audience a number of tips, emphasizing the importance of the choice of cutting wheel that’s appropriate for a given thickness of glass. As Beatty explained, “It wasn't very long ago everyone was using one wheel to do everything ... that’s incomprehensible to me now." Cutting wheels are dimensioned for each different glass cutting application, with different finishes available for different results. Beatty says he tells his operators to think of selecting their wheel finish like shopping for tires. "A regular grit wheel is kind of like a regular highway tire on your car; if occasionally you have to drive through snow or ice or mud then you might want a snow tire or all-terrain tire, and that would correlate to the coarse grit finish wheel that would allow you to get a good bite..."
The angle and footprint also are important, he added.
“In choosing the right wheel angle it's important to remember, the less energy you send into the glass while scoring the cut, the smoother the resulting edge after the break out,” Beatty said.
In talking about the cutting wheel’s footprint he reminded his audience to pay attention to the appropriate psi needed to make a cut. If an operator opts to turn up the pressure to complete the cut, the heat also is being turned up, which can lead to more sub-surface pressures - and potentially destroy the glass. Rather than turning up the pressure, Beatty advised changing the cutting wheel first, as that should be done at a regular frequency anyway. He noted that the occasional “shark’s tooth” flaw on the edge, should be a warning sign to “pay attention, operator! You’ve got to change something pretty quick if you don't want major problems."
Dave Cooper of Guardian also had some tips for cutting, specifically when it comes to handling high-performance coated glass. In his presentation he noted the importance of having the coated side of these high-performance glasses facing up during cutting so shards aren’t scratching that surface; although, he advised, the table surface should always be kept clean. He also recommended using only as much approved cutting fluid as needed and moving lites one at a time to prevent scratching.
Prior to cutting, though, Cooper reminded his audience of the importance of carefully storing coated glass. For starters, he said, “These high-performance glasses reflect solar energy, but they also absorb it, so if it's stored in sunlight it might break." These high-performance glasses should be stored out of direct sunlight and away from water, in a stable and well supported pack.
According to Cooper, though, the most important issue with handling high-performance glass is washing. "It's such an important step; it's repeated throughout the process often, and having the washer set up and running to the manufacturers specs is critical," he said. As he points out, if the glass is not appropriately washed, any following fabrication is likely to not be successful. He added, “It’s especially important not to touch the coating as it's being removed from the washer."
Bob Lang of Billco had more tips on washing glass of all types in his presentation on “Understanding and Maintaining a Glass Washing Machine.” Lang began by explaining how the pre-spray system minimizes the contamination in the washing zone portion, among other things, as it removes loose debris from glass before passing through the washer. As the glass passes through the washer, he stressed the importance of using clean water so that minerals - such as those commonly found in city water - don’t end up contaminating the glass. In addition to using clean water, regular maintenance of the machine can impact the cleanliness of the glass. Lang also noted that it’s important to maintain the drying section rolls so they stay clean and there is no contamination on the bottom of the glass.
As Lang explained it, “The thing to remember is if the inside of the glass washer is dirty, the glass can’t get clean.”
Glass Fab ends today at the Embassy Suites Kansas City International. Stay tuned to USGNN.com™ for more information on the presentations at Glass Fab.