Foundry Sand
A foundry mould is made of sand held together with a binder. The sand has to be dry, clean and consistently graded, or the casting is not.
Why foundries use quartz sand
Molten metal is poured into a mould formed in sand around a pattern, with sand cores forming the hollows. Quartz sand is the standard moulding base because it is hard, tolerates high temperatures, is available in quantity and takes a binder well. When the metal has solidified the mould is broken away and the casting cleaned.
What matters in the sand
Grain size and distribution set the surface finish of the casting and the permeability of the mould — how gas escapes as the metal is poured. Foundries specify a grading and hold to it. Moisture matters because most binder systems, particularly chemically bonded and resin systems, are sensitive to water in the sand; it has to be dry. Cleanliness matters because silt, clay and organic material interfere with the binder and gas off in the mould. And consistency matters most of all: a foundry tunes its binder addition and its process around the sand it has, and a change in the sand changes the castings.
The MRP product
Kiln-Dried Sand — quartz sand washed to remove silt and clay, dried in our kiln and screened to a close fraction between 0.3 mm and 6 mm — is produced to the foundry's grading and supplied dry. Because it is quarried, washed, dried and screened on one site from one deposit, the sand the foundry qualifies is the sand it keeps receiving.
Supply
Bulk supply to foundries and pattern shops. Tell us the grading or sieve band specified, any moisture limit, the tonnage and the delivery point.