Greasing joints

Applying grease

Grease is easiest to apply to the cone part of a ground glass joint which can then be inserted into the socket. Usually two lines of grease are applied to the cone on opposite sides, then the socket is introduced to the cone and the glassware twisted. The photos below illustrate this.

Photo of user applying grease to a ground glass joint. There is a line of grease on the cone of the joint measuring approximately 2 centimeters long.

Step 1: Applying grease 

Apply two thin lines of grease down opposite sides of the cone using a syringe of grease.

Photo showing the user inserting a greased cone into a socket. Where the grease has touched both sections of the joint, it is clear. The rest of the joint is cloudy

Step 2: Inserting a greased cone into a socket

Insert the cone fully into the socket, at this point you should notice parts of the joint becoming clear as the grease creates a seal.

Photo showing a fully greased cone and socket joint. The joint is entirely clear, with no remaining streaks of grease visible.

Step 3: Twisting the cone in the socket. 

Firmly twist the cone in the socket, rotating the piece of glassware backwards and forwards until the whole joint has become clear and there are no streaks left in the grease. At this point, the joint is fully sealed.