|Monthly Tech-Tip |
The oil adsorption of a powders (usually pigments) is defined as the number of grams of linseed oil absorbed by 100 gms of the powder. Thus this test is a measure of the ability of a powder to hold onto oil.
APPARATUS AND REAGENTS :
1. Glass weighing bottle 50 ml.
2. Glass tube
3. Marble Slab or ground glass plate
4. Sharp edged steel spatula
5. Accurate scale
6. Clear raw linseed oil
1. Weigh 15 grams of the test sample (adjust to 25 grams for low absorption materials, to 5 grams or less for high adsorption materials).
2. Fill the weighing bottle with raw linseed oil and insert the glass tube in it and weigh the bottle.
3. Place the weighed test sample on the glass plate or the marble slab.
4. Add the linseed oil from the bottle drop by drop (using the glass tube) and after each addition thoroughly mix the oil and the pigment by rubbing with the spatula.
5. Continue the addition of the oil till exactly enough oil has been incorporated to produce a very stiff paste that does not break or separate. Spread the paste on the marble slab and with the spatula gently roll the paste. It should roll without separation.
6. Reweigh the bottle with linseed oil and the glass tube.
7. Repeat the test and average the result.
A = Wt. or the test sample.
B = Initial wt. of the bottle with linseed oil.
C = Wt. of the bottle with linseed oil after the test.
Oil Adsorption = ((B-C) x 100) / A
Oil Adsorption Test Information
Test conducted primarily on materials use to make bodies or glazes.
|By Tony Hansen|
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