How to Make Gilsonite Ink Varnish

A gilsonite varnish is the base of many black inks. Making it correctly ensures clean, stable ink.

Ingredients

• Gilsonite (ink grade, low ash)
• Mineral oil or vegetable oil
• Optional: other resins or alkyds

Typical ratio

20–40% gilsonite in oil, depending on target viscosity.

Process

1. Heat oil to 150–200°C in a stirred vessel.
2. Add gilsonite slowly with good agitation.
3. Hold until fully dissolved (check on a glass slide for undissolved particles).
4. Filter to remove ash and grit.
5. Cool and store.

Quality checks

• Viscosity
• Tack
• Clarity (no undissolved particles)
• Colour

Safety

Hot oil and solvents are hazardous. Use proper ventilation and temperature control.

Example batch

Heat oil to about 180 °C, add gilsonite slowly with high-speed stirring, hold until no particles remain on a glass slide, then filter and cool.

Troubleshooting

Equipment

A jacketed vessel with temperature control and a high-shear mixer gives the best results.

Use ink grade gilsonite. See gilsonite in printing inks.