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Quantum UV Urethane Varnish How To

Genius Painter

Quantum UV Clear Urethane Varnish:
Preparation, Mixing, and Application

QuantumUV is a self-sealing, clear urethane varnish finish system specially formulated for marine brightwork. This two-part hybrid urethane provides superior protection and beauty to all timber substrates. By chemically bonding to the wood on a molecular level, this low VOC, easy-to-apply coating provides a permanent, flexible finish in even the harshest marine environments. This high solids, high build finish system is available in satin and gloss and can be applied by brush or spray application. For interior or exterior use above the water line only.


  • QuantumUV Clear Urethane Varnish Base (Gloss)
  • QuantumUV Clear Urethane Varnish Base (Satin)
  • Quantum99 Urethane Brushing Activator
  • Quantum Brushing Reducer
  • Quantum99 Urethane Spray Activator
  • Quantum99 Urethane Spray Reducer
  • Quantum99 Urethane Accelerator

Surface Preparation

The surface preparation advice provided, and equipment suggestions, can be used as a guide. Preparation techniques and results will vary according to individual conditions, equipment age, and other factors. Testing on a non-critical area should be carried out prior to full-scale preparation.

Any cracks in the timber should be epoxy filled or splined with timber prior to sanding. Radius all edges to ensure that no sharp corners remain. Oxalic acid based teak cleaners can impair cure of QuantumUV and should be avoided. If timber is badly weathered, scrub with the grain using a stiff-bristled wire brush and running water to remove all grey timber from the surface before sanding.

Remove all previous coating systems and contaminants. The surface of the timber should be mechanically removed until coloration is even and the original timber tone has been exposed. All substrates must be sanded using no finer than 150 grit sandpaper. If bare timber has been saturated with saltwater at any stage, scrub well with fresh water to remove salt deposits from the timber before commencing sanding. If the timber gets wet after the final sand, water spots may appear. Re-sand these areas with 150 grit sandpaper before sealing.


BRUSH APPLICATION: To 2 parts Quantum99 Clear Urethane Varnish Base (gloss or satin) slowly add 1 part Quantum99 Urethane Brushing Activator by volume. Agitate to ensure complete mixing. Though not normally required, a 10-30% reduction with Quantum Brushing Reducer may help to achieve desired results, especially on the finish coat. Additional reduction may be used for prime/seal coat depending on substrate porosity. EXAMPLE: 8 oz. Quantum99 Clear Urethane Varnish Base, 4 oz. Quantum99 Urethane Brushing Activator, and 1-4 oz. Quantum Brushing Reducer, as desired.

SPRAY APPLICATION: To 1 part QuantumUV Clear Urethane Varnish Base (gloss or satin), slowly add 1 part Quantum99 Urethane Spray Activator by volume. Agitate to ensure complete mixing. Though not normally required, a 10% reduction by volume of the admixed varnish with Quantum99 Urethane Spray Reducer or Quantum Cool Weather/Fast Reducer may be used for proper application, film thickness control, and a smooth film appearance.

To reduce cure time, add Quantum99 Urethane Accelerator, taking care not to exceed 1 oz. (30ML)/mixed gallon. The accelerator will maintain the 75°F cure profile when added at 5 ML/mixed gallon every 5°F below 75°F. At 75°F, 1 oz. (30 ML)/mixed gallon will reduce the Dry to Tape time to 4 hours; the Dry to Touch time to 1 hour. Quantum99 Urethane Accelerator can be used at temperatures up to 100°F, though caution should be taken as pot will be reduced.


BRUSH APPLICATION: QuantumUV can be applied at a greater rate than a standard varnish. This system is self-leveling--do not overwork the surface and aim to keep wet edge times under 2 minutes, depending on the temperature.

  • For large flat surfaces, high-density foam rollers offer the best means of coverage and flow (some brush tipping may be required, but most overlap and foam will disappear as the coating continues to flow).
  • For small areas and railings, dense synthetic brushes yield the best results.

SPRAY APPLICATION: QuantumUV can be applied by air atomized spray gun (fluid tip 1.4-2.0).

PRIME/SEAL COAT: Apply a heavy coat using adequate pressure to completely wet out wood grain. Brush/roll with the grain, making sure the surface becomes completely saturated with coating. Wait approximately 4 hours between coats (or when paint is dry through, if accelerated). For best results, apply the first two coats on Day 1, wait at least 12 hours and sand with 320 or finer grit sandpaper before final coat. More coats may be necessary with excessive grain raise. Sand with 320 or finer grit sandpaper between applications. Repeat above procedure until desired build and smoothness is obtained.

FINAL COAT: Sand the prime/seal coat with 320 grit sandpaper, being careful not to sand through the coating. Reduce 10-20%, as needed, with Quantum Brushing Reducer to achieve desired appearance.

NOTE: Application of these product systems requires recommended temperature/humidity conditions and film thickness ranges. The material, hangar, and substrate (application surface) temperature should be no lower than 45°F before, during, and after application. Do not apply paint materials to surfaces less than 5°F above dew point, or to surfaces warmer than 125°F. Substrate temperature should be minimum 45°F to maximum 125°F.


Use with adequate ventilation and proper respiratory protection. See MSDS for complete details of composition and precautions.

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