Gilsonite in Electrical Insulation Compounds

September 13, 2026 · 1 min read · Sun Gilsonite Technical Team

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Gilsonite in Electrical Insulation Compounds – Basekim printed bag for drilling mud conditioner

Gilsonite was historically used for insulating cables and is still used in some potting and insulating compounds.

Properties

Good dielectric properties
Water resistance
Hardness

Historical use

In the late nineteenth and early twentieth centuries gilsonite was used to insulate underground cables and electrical windings. Its high resistivity and water resistance made it ideal before modern plastics existed.

Basekim printed bag for drilling mud conditioner – additives application

Present-day uses

Potting and filling compounds for junction boxes
Battery sealing compounds
Some insulating varnishes and impregnating compounds

Properties that matter

Property	Relevance
Dielectric strength	Prevents electrical breakdown
Water resistance	Maintains insulation in humid conditions
Softening point	Prevents flow when equipment heats up

Formulation

Gilsonite is blended with bitumen, waxes or oils to adjust hardness and pouring temperature. Always test the electrical properties of the final compound against the relevant standard.

See gilsonite powder and history of gilsonite.

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Data sheet

Gilsonite Powder

Data sheet – Gilsonite Powder
Property	Typical value	Test method
Appearance	Black to dark brown powder	Visual
Particle size	100 – 200 mesh	Sieve
Softening point (R&B)	150 – 220 °C	ASTM D36
Ash content, max	5 %	ASTM D3174
Moisture, max	1 %	ASTM D95
Volatile matter	55 – 75 %	ASTM D3175
Solubility in toluene, min	99 %	ASTM D2042
Specific gravity @ 25°C	1.04 – 1.10	ASTM D70
Typical dosage	Drilling 2–8 lb/bbl · asphalt 4–12 % of binder · foundry 0.3–1.0 %
Packing	25 kg multi-wall paper or PP bags, palletized and stretch-wrapped; 1 MT jumbo bags.