Stopcock grease applying

Did you apply the stopcock grease properly, or is the current grease old ... 

Leaks at Demountable Seals. These leaks are caused by wear, old stopcock grease, poorly applied grease, poor alignment, twisted or worn O-rings, inadequate stopcocks or joints, mismatched plugs and barrels, or dirt between pieces. This list is by no means complete, but it gives you an idea of the range of problems. 

Sample Introduction and Distillation Remove the separatory funnel, and quantitatively transfer the sample in aqueous ethanol to the flask. Wipe the tapered joint clean with a laboratory tissue, apply stopcock grease to the outer joint of the separatory funnel, and return the separatory funnel to the tapered joint flask. The nitrogen flow through the 3% Hydrogen Peroxide Solution should resume as soon as the funnel is reinserted into the appropriate joint in the flask. Examine each joint to ensure that it is sealed. 

Because of the unstable nature of ozone, the usual techniques for determination of physical properties can rarely be applied. Contact with many materials generally used in experimental work, such as rubber tubing, organic stopcock grease, and mercury, must be avoided. The quantity of pure liquid ozone must be kept small in the interests of safety. Even 1 ml. of undiluted liquid ozone can cause a disastrous explosion unless suitable precautions are taken to protect the experimenter. 

The two-way stopcock allows the gas to flow either into analysis vessel B or into reaction vessel 0. It is best to lubricate it with PsO, which is then converted to HPO 3. To prevent too rapid liquefaction of the acid (which would produce a leak), ordinary stopcock grease is applied at the top and bottom rim of the stopcock. Stopcocks which close at the bottom are also very useful. All other stopcocks in the apparatus can be sealed with ordinary stopcock grease. 

Fig. 8.2. Application of grease to joints and stopcocks, (a) Grease is applied in several thin stripes which run parallel to the direction of the male joint. A wooden splint may be used to apply the grease to avoid contamination by moisture or dust on fingers. (6) The joint is worked together with an oscillating motion and slight steady pressure.

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