Ask A Scientist© General Science Archive

name         Peter
status       other
age          60s
Question -   I have been endeavouring to find a simple formula for
waterproofing canvas and have repeatedly come across one using 3 cups of
soya bean oil and 1.5 cups mineral turpentine.

Soya Bean oil is not readily available in Australia and is expensive can I
use others?

I believe that Soya Bean oil is a polyunsturated oil could I use a
polyunsturated vegetable type oil such as sunflower, peanut or 
cottonseed oil?

What reaction takes place between the soya bean oil and the turpentine. I
have heard that it is something to do with ions.

Here is a formula you might want to try.  Careful, it is definitely 
flammable.  It
comes from the book Super Formulas by White.

2 cups boiled linseed oil
2 ounces (weight) beeswax
2 ounces (weight) rosin

Heat the beeswax and rosin to 250 degrees F until they are melted and 
combined.
Remove from heat and stir in the oil.  Apply three coats to the stretched 
canvas.
Allow one day between coats.

Larry Krengel
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