Plainsman Clays | DARV
Darvan No. 7
Darvan 7 is a deflocculant supplied ready mixed as a liquid, a solution of a sodium polymethacrylate polymer in water. It lets a casting slip hold a high load of solids and still pour.
$0
Suggested retail price. In-store prices and availability may vary by location.
Darvan 7 keeps clay particles repelling one another, so a slip stays fluid where a slurry without it would be too thixotropic. A slip made with it is slow to thicken on standing, cast ware can sit in the mould for a long time without cracking, and the plaster absorbs very little of the polymer, so scrap will usually go back to slip with water alone. Casting bodies commonly use a fraction of a percent, measured against the dry weight of the body, and up to about one percent.
- A deflocculant supplied ready mixed as a liquid
- A long chain organic polymer, not a small inorganic ion
- A forgiving casting window and a long set in the mould
- Alkaline, which is the condition the polymer needs to work
- Lowers thixotropic properties
- Prevents thickening of standing slurries
- Offers high resistance to over-deflocculation
