Overview:
This manual, written in 1914 by Francis C. Frary, provides a comprehensive guide to glass-blowing techniques for scientists and laboratory workers. It emphasizes the importance of using high-quality soda glass and avoiding devitrification, a common issue with old or poorly annealed glass. The manual outlines basic operations like cutting, bending, constricting, and flanging glass tubes. It then progresses to more complex techniques like joining tubes of varying diameters, blowing bulbs, and sealing tubes through other tubes.
Frary details each operation with meticulous precision, recognizing the challenges faced by beginners and providing detailed instructions to overcome them. While the manual doesn’t delve into the creation of specialized instruments like stopcocks or thermometers, it covers essential skills needed for creating and modifying laboratory apparatus.
Key Findings:
- Glass selection: Choosing the right type of glass is crucial for successful glass-blowing. Soda glass is the preferred choice due to its moderate working temperature and resistance to devitrification.
- Proper annealing: Annealing prevents glass from cracking due to temperature changes. This involves slow heating and cooling to minimize stress on the glass.
- Rotation: Uniform rotation of the glass tube during heating and manipulation is vital for achieving even heating and maintaining shape.
- Avoiding lumps: Minimizing lumps formed when joining tubes is essential for creating seamless and durable joints.
- Avoiding uneven wall thickness: Uneven wall thickness can cause weaknesses and lead to cracking.
Learning:
- Glass properties: The reader will gain an understanding of the different types of glass used in laboratories, their properties, and how to select the most suitable type for various tasks.
- Basic glass-blowing operations: The reader will learn essential glass-blowing techniques like cutting, bending, constricting, and flanging.
- Advanced glass-blowing techniques: The reader will acquire skills for joining tubes, blowing bulbs, and sealing tubes through other tubes.
- Understanding devitrification: The reader will learn about devitrification, its causes, and how to prevent it.
- Annealing importance: The reader will gain insight into the importance of annealing and the correct procedures for annealing various glass objects.
Historical Context:
The manual was written in 1914, a time when glass-blowing was a vital skill for scientists working in laboratories. While many laboratories had professional glass-blowers, the need for skilled technicians existed as many laboratories were located in remote areas. This manual aimed to equip scientists with the necessary knowledge to perform basic repairs and modifications on glassware, saving time and money compared to sending broken equipment long distances.
Facts:
- Soda glass is the most common type of glass used in laboratories today. This is because soda glass has a moderately low working temperature and is resistant to devitrification.
- Lead glass is rarely used for laboratory glassware. This is because lead glass tends to blacken unless worked in a strongly oxidizing flame.
- Devitrification is a common problem in old glass. This is because the alkalis in the glass can volatilize over time, leading to a crystalline surface.
- Proper annealing is essential for preventing glass from cracking. This involves heating and cooling the glass slowly to minimize internal stress.
- The “hissing” flame is used to work lead glass. This flame has a large excess of air and helps to oxidize the lead oxide, preventing blackening.
- The working temperature of glass is determined by trial. This is because the temperature at which glass softens varies depending on its composition.
- Air bubbles in the original glass batch can become trapped during manufacture. This creates microscopic tubes in the glass, which can collapse and form bubbles during working.
- Uneven wall thickness in glass tubing can make it unsuitable for glass-blowing. This is because the thicker and thinner areas cool and contract at different rates, leading to stress.
- A glass-knife is preferred to a file for cutting cold glass. This is because it creates a narrower scratch, which is more likely to initiate a clean break.
- The “tee” tube is a common glass-blowing component. This is a piece of tubing with a side branch, used for connecting different parts of a laboratory apparatus.
- The “tee” tube is usually made using the second method of joining tubes. This is because the first method can be difficult to apply with the side branch.
- A carbon rod or wire is used for flanging larger tubes. This is because the heat from the flame can deform a metal flanging tool when used on larger tubes.
- A bulb blown on the end of a tube can be used to collect glass for making a larger bulb. This is a common technique for making bulbs of larger diameters.
- A series of small bulbs can be blown on a single tube. This is useful for creating a variety of bulbs for different purposes.
- A bulb blown in the middle of a tube can be used to create a larger bulb. This is an efficient way of making large bulbs, as it avoids the need to collect glass from a smaller tube.
- Capillary tubing is commonly used for gas analysis. This is because it provides a small and narrow channel for gas flow.
- Closed circuits of tubing are often used in laboratory equipment. This is because they allow for the flow of liquids or gases in a continuous loop.
- Spirals of glass tubing can be made freehand. This technique is used for creating various types of spirals for different applications.
- Ground joints are used to connect pieces of tubing. This is a more precise method of joining tubes compared to sealed joints.
- Platinum wire can be sealed into glass tubes. This is done by using a special glass with a similar coefficient of expansion to platinum.
Statistics:
- 20% royalty fee: This is the fee charged for commercial redistribution of Project Gutenberg eBooks.
- 100-mesh sieve: This is the recommended mesh size for sieving sand used for grinding stopcocks.
- 1⁄4-inch diameter: This is the recommended diameter for tubing used for the “tee” tube exercise and other basic glass-blowing exercises.
- 1⁄4-inch or less: This is the recommended diameter for platinum wire to be sealed into glass without using special glass.
- 3⁄32 to 1⁄8-inch diameter: This is the recommended diameter for the globule of special glass used for sealing platinum wire into tubes.
- 3⁄4-inch diameter: This is the common external diameter for tubes used in the Carius method for halogen and sulfur determination.
- 3⁄32-inch wall thickness: This is the common wall thickness for tubes used in the Carius method.
- 18 inches: This is the recommended length of tubing to use for making a string of bulbs on a single tube.
- 1-1⁄4 to 1-1⁄2 inches: This is the recommended length for the glass cylinder collected for making a bulb on the end of a tube.
- 1-1⁄2 inches: This is the maximum diameter for a strong bulb on ordinary 1⁄4-inch tubing.
- 6 inches: This is the recommended length for the large tube used in the gas-washing tube exercise.
- 4 inches: This is the recommended length for the tube to be sealed through the large tube in the suction pump exercise.
- 2 inches: This is the recommended length for the inlet tube in the suction pump exercise.
- 2-1⁄2 to 3 inches: This is the recommended length for the tail of the tube used for sealing the second tube through the first tube in the suction pump exercise.
- 2 inches: This is the recommended length for the tube containing the substance to be weighed out in the Carius method.
- 1⁄16-inch or a little less: This is the recommended wall thickness for the large tube used in the suction pump exercise.
- 1⁄16-inch or a trifle over: This is the recommended wall thickness for the larger tube in the exercise joining two tubes of different diameters.
- 1-1⁄2 inches: This is the recommended length for the delivery tube in the gas-washing tube exercise.
- 7 or 8 inches: This is the recommended length for the piece of 3/8-inch tube used in the suction pump exercise.
- 1⁄8 inch or less: This is the recommended distance from the tube where the tail is cut off when sealing a platinum wire.
Terms:
- Devitrification: The process of glass crystallizing and becoming brittle, often caused by the loss of alkalis.
- Annealing: A heat treatment process where glass is slowly heated and cooled to minimize internal stress.
- Blowpipe: A tool used to direct a controlled flame for glass-blowing.
- Capillary tubing: Thin-walled tubing with a very small internal diameter, often used in gas analysis.
- Constriction: A narrowed section of a tube, created by pushing the glass together while it is hot.
- Flange: A thickened rim at the end of a tube, often used to strengthen the opening.
- Ground joint: A connection between two pieces of glass with a precisely ground surface, ensuring a tight seal.
- Hissing flame: A flame with a large excess of air, used for working lead glass to prevent blackening.
- Tail: A long, thin extension of a tube, used for manipulating the glass and drawing it out.
- Working temperature: The temperature at which glass becomes soft enough to be worked.
Examples:
- Gas-washing tube: This is a common piece of laboratory equipment used for removing impurities from gases. The exercise demonstrates how to seal a smaller tube through a larger one, creating a passage for gas flow.
- Suction pump: This is a simple pump used to create a vacuum. The exercise demonstrates how to seal a smaller tube into the end of a larger one, creating a passage for air flow.
- Kjeldahl trap: This is a specific type of glassware used in the Kjeldahl method for determining nitrogen content. The exercise illustrates how to seal a small tube into a bulb.
- Bulb at the end of a tube: This is a common glass-blowing component used for various purposes. The exercise shows how to collect glass on the end of a tube and then blow it into a bulb.
- Bulb in the middle of a tube: This demonstrates how to blow a bulb in a tube, using a piece of glass tube with a tail on one end.
- Joining tubes of different diameters: This exercise demonstrates how to connect a smaller tube to a larger one, using techniques for shrinking and blowing to ensure a seamless joint.
- Capillary tubing: This illustrates how to work with capillary tubing, using techniques for joining, blowing, and creating a “tee” branch.
- Closed circuit of tubing: This example showcases how to create a continuous loop of tubing, considering the challenges of contraction and using techniques for managing stress.
- Spiral: This example illustrates how to make a spiral of glass tubing freehand, using a controlled flame and precise rotation.
- Ground joint: This exercise shows how to create a ground joint connection between two tubes, using grinding techniques to ensure a precise fit.
Conclusion:
This manual provides a valuable resource for anyone seeking to learn the art of glass-blowing for scientific purposes. It covers fundamental techniques, addresses common challenges faced by beginners, and outlines advanced techniques for creating specialized glassware. The manual emphasizes the importance of using high-quality glass, proper annealing, and meticulous manipulation to achieve durable and functional laboratory equipment. By understanding the principles of glass-blowing, laboratory workers can save time and money by performing repairs and modifications on their own.