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Home Page --> Miscellaneous Glassblowing Tips and Tricks
Use a kerosene heater as a "temporary annealer". The heater I had used was about the size of a 5 gallon can and was the sole source of heat in the unfinished New England garage where I had my shop. I've placed newly fabricated, water -jacketed flasks with multi-ring seals on top of the kerosene heater to hold until I had a batch of glassware ready for transport to an oven 6 miles away for proper annealing. The heater serves as a transition stage to cooler temperatures, yet produces enough heat to protect the glassware from cold drafts, preventing possible thermal shocks. Note: Be sure you have adequate ventilation when using kerosene heaters.
The Corning Museum of Glass has a web page with an excellent video that demonstrates stress in unannealed and properly annealed objects.
Typical flat glass cutting tools.
The Fletcher Terry Company
|1. Be sure at least one end of your scratch or score goes to the edge of the plate. Line (a) will not break as cleanly as lines (b) and (c).
2. Curved lines can be produced and cut as well. Make one good score by applying even pressure on the glass with the cutting tool. Repeated scoring will not make the glass break easier or produce a clean cut.
3. Wet the scratch with water (a spray bottle will work fine) just prior to breaking. If glass pliers are used, apply them at the edge where the scratch ends. If using the "tap" method, tap on the glass surface opposite the scratch. Start at the scratch end and follow or chase the break across the glass plate.
|4. An alternate way of breaking the glass plate is to place a very small diameter
rod (c) under the glass plate opposite side of score (b). Wet the scratch. Holding end (a) firmly down, press down on end (d).
If you are attempting to remove a strip of glass less than 25mm in width, it is recommended that glass pliers or the "tap" method be used.
Cutting tools come in different forms and wheel angles. Wheel angle guidelines are 130-140° for window (float) glass and 88-114° for borosilicate glasses.
Fletcher-Terry Company has additional information on glass cutting wheels. You can also request their white paper, "The Principles of Glass Cutting".
Use the same slow speed as in using metal cookie cutters. Start glass drill contact slowly without much downward pressure. Allow for equal material loss from the glass drill as in the glass plate being drilled.
This seal can be used on borosilicate and other glasses as well.
Solution: An evacuated quartz ampoule with thin "break away" bulb.
This type of sample collector can be easily modified by using other types of glass and methods of breaking glass bulb.
Objective: 1/2" OD Quartz tube
Material needed: 10 mm ID x 13 mm OD quartz stock and a machined graphite rod 0.374" diameter
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