Gilsonite for Heavy-Section Castings

June 5, 2026 · 1 min read · Sun Gilsonite Technical Team

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Large castings — machine bases, mill parts, counterweights — remain hot for a long time, increasing the risk of penetration and burn-on.

Challenges

Some foundries use a facing sand with higher gilsonite content against the pattern, backed by ordinary system sand.

Measure	Benefit
Facing sand with extra gilsonite	Better surface at critical areas
Refractory coatings	Barrier against penetration
Chills	Faster local solidification
Higher mould hardness	Less metal penetration

Heavy castings need longer cooling, which also means longer exposure of sand to heat. Plan shake-out timing carefully.

Data sheet

Data sheet – Foundry Grade Gilsonite
Property	Typical value	Test method
Appearance	Black powder	Visual
Particle size	100 – 300 mesh	Sieve
Volatile matter	55 – 75 %	ASTM D3175
Ash content, max	5 %	ASTM D3174
Moisture, max	1 %	ASTM D95
Softening point (R&B)	150 – 200 °C	ASTM D36
Typical dosage	0.3 – 1.0 % (iron)
Packing	25 kg bags palletized; 1 MT jumbo bags for blending plants.