Glass is a delicate material which is used in manufacturing various things. There are two types of glass like Soda-lime glass and Borosilicate glass. Soda-lime glass can be melted easily at 300-400°C and Borosilicate glass cannot be easily melted and it requires 700-800°C to soften it. Hence Borosilicate glass is used in manufacturing glass apparatus used for laboratory purpose.
Aim:
To know the basic techniques of cutting glass tube and glass rod using a simple process.
Materials Required:
- 15 cm long Soda-glass tube
- 15 cm long Soda-glass rod
- Triangular file
- Bunsen Burner
Experimental setup:
Procedure:
- Place the rod or glass tube on the table.
- Mark the glass tube or rod with triangular file keeping.
- Keep the triangular file perpendicular to rod or tube and pull it towards you so that a single deep scratch is made.
- Hold the glass rod or tube with the help of thumbs as shown in the figure
- Now apply pressure in the direction away from you and try breaking the glass rod or tube.
- Note: if the glass rod or tube does not break, make a deeper scratch using the triangular file on the mark done earlier.
- If you see any jagged edge, Trim it by striking with a wire gauge.
- Gently hold the cut edge of the glass rod or tube in the flame to give a good finish.
- For fire polishing, hold the edge of glass rod or tube in the bunsen burner and then rotate it back till both the ends get a good finish (smooth and round).
Precautions to be taken during the experiment:
- Try to make a single deep scratch of required length in a single stroke/attempt.
- Be cautious while carrying out the filing process and while breaking of the glass tube/rod.
- Keep your face far and hold the glass tube/rod away with the help of a piece of cloth to get optimum balance.
Frequently Asked Questions on Cutting Glass Tube And Glass Rod
Why glass does not possess a sharp melting point ?
Glass is an amorphous solid crystalline structure having tightly packed molecules. Hence Glass does not possess a sharp melting point.
Why is it required to round off the freshly cut edges of the glass tube or the glass rod ?
The jagged edges might cause injury while handling, hence for the safety and to give good look with a smooth finish, edges of glass tube or rod is rounded off.
Why a glass tube is rotated while heating in a burner ?
To ensure the uniform heating glass tube is rotated while heating.
Which type of glass softens easily ?
soda lime glass
Mention the various steps which are involved in the cutting of a glass tube ?
- Scratching
- Breaking
- Heating the cut edges
- Cooling
