Viscosity Oils

Manual Temperature Adjustment - For the technician who does not have automatic temperature control equipment, the following procedure may be useful with viscosity dip type cups: If the oil to be used is below temperature, place the bottle with the cap slightly loosened no closer than about one foot from an incandescent desk lamp. This will slowly raise the temperature of the oil. When within about one degree of measuring temperature, transfer the required amount of the oil to a glass container of sufficient height and diameter to accommodate the viscosity cup. (Glass is recommended due to its low rate of temperature conductance). Place the viscosity cup to be used in the oil in the glass container so that it comes to the same temperature as the oil and place a thermometer, preferably glass, in the oil which can also be used as a stirring rod. If necessary, to elevate the temperature slightly, simply hold the glass snugly in the hand while stirring the contents gently and observing the change in temperature. If necessary, to lower the temperature, dip the bottom of the glass container for a few seconds in water that is 10 to 20 degrees lower than measuring temperature and continue gentle stirring while the temperature slowly lowers. With a little practice it is possible to make measurements very close to the target temperature.

Guide for removing the calibrated oil from Gardco viscosity cups - Any remaining material in the cup must be removed by flushing with a suitable solvent. Light naphtha, heptane, octane, highly aromatic solvents, and or any other petroleum-derived hydrocarbon solvent can be used. Varsol® is a commercial solvent that works very well for this purpose. Varsol is a registered trademark of the Exxon Company. Completely dry the viscosity cup with a lint free cloth. Use a highly volatile solvent for a second cleaning as since any remaining hydrocarbon solvents from the first process will evaporate quickly after the sample has been flushed from the cup. Hypersolve, MEK and Alcohol can be used in aluminum cups and Hypersolve and Alcohol for the stainless steel cups. Acetone is commonly used as the second solvent because of its high volatility and its ability to dissolve traces of petroleum solvents and water. In the third process a low velocity stream of clean air will be sufficient to evaporate remaining traces of any volatile solvent. Be aware, avoid rapid evaporation of these solvents as this can cool the surface to such an extent that humid air may be brought below the dew point, causing a film of water to form on the cup.

Viscosity oils available from the Paul N. Gardner Company are NOT recommended for use with cups produced by other suppliers unless the conversion formula between centistoke viscosity and efflux time as well as cup production tolerance for the particular cup in question has been furnished.