Thick compositions or putty fillers are composed of whiting and plaster, or similar powders having little or no colour.
"French Polishing and Enamelling" by Richard Bitmead
Stir in enough powdered whiting to make a thick putty.
"Practical Taxidermy" by Montagu Browne
The putty is an oxyde of tin, in form of powder.
"Popular Technology; Volume 2" by Edward Hazen