Basic laboratory procedures II

When carrying out experiments it is vital that all apparatus is held in place securely during the procedure. It is essential that you know how to assemble supporting and securing equipment to the highest possible standards of safety. The most common types of supporting and securing equipment are shown in Fig. 5.1. 

These are also known as retort stands and comprise an aluminium or steel rod screwed into a heavy metal base. Always eheck that the base sits level and that the rod is tightened fully in place. 

These are also described as clamp bosses or bosses . Make sure that the locking screws move freely and are not distorted. When you attach the clamp holder to the support stand, tighten the screw firmly and ensure that the open slot to be used for the clamp is pointing upwards (Fig. 5.2). 

Conical flasks should be clamped at the neck and ground-glass jointware should be clamped at the joint - this usually has the greatest thickness of glass. 

In most clamps, only one of the jaws moves when turning the screw. When you use the clamp in a horizontal position, make sure that the movable jaw is at the top (see p. 109). 

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