USC laboratories use glassware daily in a variety of ways. Improper use or mishandling may lead to accidents, broken glass, and injuries. Here are tips on how to avoid common mishaps and injuries when working with glassware.
- Handling Glassware with Sharp Edges
- Attaching Hoses/Tubing to Glassware
- Unfreezing Glass Joints
- Washing Glassware
- Using NMR Tubes
- The DOs and DONTs of Glass Pipette Use
- Glassware Disposal
Supplemental information on glassware maintenance and safety is available at: https://sp-wilmadlabglass.com/technical-documents/
Handling Glassware with Sharp Edges
Researchers often make their own substrates (e.g., for thin film deposition) by first cutting microscope slides or ITO-coated glass plates with handheld scorers and then breaking them along diamond-scored lines. This produces sharp/very sharp edges. To avoid injury, remember to:
- Wear cut-resistant gloves under disposable nitrile gloves for extra protection when cutting glass or handling substrates.
- Thinner grades of uncoated, cut-resistant glove are suitable (see ANSI Level A1 to A9 Protection).
- See examples of knit uncoated cut-resistant gloves. NOTE: Medical suppliers also sell particularly thin high-dexterity cut-resistant under-gloves designed for use by surgeons, but they can be more expensive than the gloves sold by industrial suppliers.
- Examine cut pieces for dangerously sharp protrusions, corners, or razor edges. This is especially critical when prepping pieces for use as substrate. NOTE: The pieces are typically rubbed together between thumb and index finger with detergent and water.
- Smooth off the sharp protrusions and corners using an abrasive stone (diamond (resin bonded, metal bonded, or electroplated), silicon carbide, and alumina stones) or discard.
- Diamond stones require the least amount of effort and stay sharp the longest.
- Silicon carbide is second best for use on glass. Silicon carbide abrasive paper (waterproof grade) is also suitable.
- Abrasives are recommended to be used wet on glass, to prevent clogging and eliminate dust. A medium abrasive grit size is recommended.
Attaching Hoses/Tubing to Glassware – Figures 1 and 2 below illustrate how to attach hoses/tubing to glassware.
Figure 1. Attach tubing to hose barb
Figure 2. Attach tubing to hose adapter.
Unfreezing Glass Joints – Glass joints may freeze/lockup if left together over time unlubricated, exposed to adhesive chemicals, or exposed to strong bases that “freeze” them together. Due care is needed to unfreeze them safely and without damage – follow steps illustrated in Figure 3 .
Figure 3. Unfreeze glass joint with heat gun.
Prevent freezing/locking by applying silicone grease, fluorocarbon grease, PTFE sleeves, or PTFE thread tape to the glass joints. Figures 4 and 5 illustrate greasing and taping techniques. Review the quick reference guide in Table 1 below for advantages and disadvantages of select greases.
Figure 4. Applying grease to glass joints.
Figure 5. Applying teflon tape to glass joint.
Table 1. Advantages and disadvantages of select greases.
| Grease Type | Pros | Cons | Examples |
|---|---|---|---|
| Silicone | Inexpensive, readily available, residue easily removed using a base bath | Soluble in low polarity solvents (e.g. hexanes), thixotropic – joints may be hard to disassemble after a long time. | N/A |
| Fluorinated grease | Teflon thickener usually keeps joint from freezing after long storage, non-thixotropic, low friction/viscosity makes it good for greasing valves, virtually insoluble in all common solvents | Expensive (however, only very small amounts are needed as it has excellent spreading ability in glass joints) | Krytox ™ |
| Hydrocarbon grease | Low vapor pressure, does not cause silicone contamination. Residue easily removed with organic solvents (this can be a pro or a con, depending on the application). | Expensive, soluble in a wide variety of solvents, low heat resistance. Normally not suitable for general use (e.g. conical glass joints); more suitable where silicones or fluorinated grease cannot be used (e.g. some high vacuum systems) | Apiezon ™ |
Washing Glassware – Simple rules
- Do Not leave sinks filled with glassware.
- Do Not overfill base baths as this increases the risk of breakage.
- Always inspect glassware for damage (e.g., chipped, star-crack)
- If chipped glassware must be washed by hand, use a brush rather than washing with a cloth or directly with fingers.
- Sharp edges of chipped glassware can be smoothed using an abrasive stone or silicon carbide paper.
Using NMR Tubes – Follow steps in Figure 6 to extend the use of fragile NMR tubes.
Figure 6. Extend use of NMR tubes.
The DOs and DONTs of Glass Pipette Use – Figures 7 and 8 illustrate the DOs and DONTs of glass pipette use.
Figure 7. Glass pipette use DOs.
Figure 8. Glass pipette use DONTs.
Glassware Disposal – Figure 9 illustrates various containers used for glassware disposal.
Figure 9. Containers for glassware disposal.
