Hempel Silic One Propeller Kit

Hempel’s Silic One Propeller Kit is a biocide-free fouling-release system for marine propellers and stern gear below the waterline. The kit contains 375ml of Hempel’s Silic One Tiecoat 27450 and 375ml of black Hempel’s Silic One 77450. Its silicone and hydrogel technology creates a smooth, low-friction surface that makes it difficult for fouling organisms to attach and supports self-cleaning while the propeller is in use.

The Silic One Propeller Kit combines the adhesion stage and the fouling-release topcoat in one 750ml pack. Hempel’s Silic One Tiecoat is a high-solids, silicone-based tiecoat that bonds the primer system to Hempel’s Silic One. The black Silic One topcoat forms the final glossy, low-friction surface.

This is a fouling-release system rather than a conventional biocidal antifouling. It does not release biocides into the water. Instead, its hydrogel micro-layer gives the coated surface water-like properties, reducing organism attachment and helping growth release as the propeller rotates and the vessel moves through the water.

Kit Contents

• 1 x Hempel’s Silic One Tiecoat 27450, Yellow 23410, 375ml
• 1 x Hempel’s Silic One 77450, Black 19990, 375ml
• Total coating volume: 750ml

Hempel’s Light Primer 45551 is not included. A bare or untreated propeller must be prepared and epoxy primed before the supplied Tiecoat and Silic One topcoat are applied.

Compatibility and Intended Use

The propeller system is intended for exterior use below the waterline. Hempel states that it can be applied to all types of propeller metals and alloys. Epoxy- and glass-fibre-based composites may also be coated when the correct primer system is used.

For bare or untreated propellers, Hempel’s propeller specification uses two coats of Hempel’s Light Primer, followed by one coat of Hempel’s Silic One Tiecoat and one coat of Hempel’s Silic One. Silic One must not be applied directly to an uncoated surface; it is applied only over the specified Tiecoat.

Surface Preparation

Remove all existing antifouling from previously coated propellers. Clean the substrate with a suitable detergent such as Hempel’s Pre-Clean. When cleaning aluminium propellers with Hempel’s Pre-Clean, dilute it 1:20 as specified by Hempel.

Create a clearly perceptible surface profile using 40-grit abrasive paper or another mechanical preparation method; abrasive blasting is preferred where suitable. Wash with fresh water and allow the surface to dry completely. Apply the primer as soon as possible after preparation to reduce the risk of oxidation.

Application System

1. Apply the first coat of Hempel’s Light Primer, thinned 20% in accordance with the primer instructions.
2. Apply the second coat of Hempel’s Light Primer, thinned 5% in accordance with the primer instructions.
3. Apply one full coat of Hempel’s Silic One Tiecoat 27450.
4. Apply one full coat of Hempel’s Silic One 77450, using as much product as possible without causing runs or sagging.

Stir both supplied coatings thoroughly before use. Apply by brush or roller using soft, even strokes and ensure complete coverage. Neither the Tiecoat nor the Silic One topcoat may be thinned. Hempel’s Thinner 808, product code 08081, is specified for cleaning tools.

The surface temperature must remain above 10°C during application and curing. Relative humidity must remain between 30% and 85%. Provide sufficient ventilation and avoid condensation on the freshly applied coating.

Overcoating and Immersion

At 20°C, overcoat the first Light Primer coat after 4 hours and within 30 days. Apply the Silic One Tiecoat over the second Light Primer coat after 2–4 hours. Apply the black Silic One topcoat over the Tiecoat after 8–48 hours.

At 10°C, the corresponding intervals are 8 hours to 60 days, 4–8 hours and 16–48 hours. At 30°C, the intervals are 3 hours to 22 days, 1–2 hours and 4–24 hours.

After the final Silic One coat, allow at least 24 hours before immersion at 20°C or 30°C, or at least 36 hours at 10°C. The maximum time before immersion is one month.

Coverage and Technical Performance

Both supplied coatings have a theoretical spreading rate of 10m²/L at their specified reference film thicknesses. Each 375ml component therefore provides approximately 3.75m² of calculated theoretical coverage. Practical coverage will be lower on complex propeller geometry and where application losses or a heavier non-sag film increase consumption.

The Tiecoat has a recommended dry film thickness of 70µm and the Silic One topcoat has a recommended dry film thickness of 80µm. Both products have a pot life of approximately 60 minutes at 20°C once the container is opened for use.

Cleaning and Maintenance

Self-cleaning is most effective at higher operating speeds, although Hempel states that self-cleaning can also occur at lower speeds with regular use. Where manual cleaning is needed, use a dense sponge or cloth and rinse with fresh water, or use a fresh-water pressure wash within Hempel’s stated limit. Do not use a hard brush or stiff bristles on the silicone surface.

Where the coating is damaged, rebuild the specified coating system over the affected area. Traditional antifouling will not adhere directly to Silic One; the silicone coating must be removed before changing back to a conventional antifouling system.

Key Features

• Hempel Silic One Propeller Kit, part number HP-7745P-99980
• Biocide-free silicone and hydrogel fouling-release system
• Designed for propellers and stern gear below the waterline
• 375ml Silic One Tiecoat 27450 included
• 375ml black Silic One 77450 topcoat included
• Total supplied coating volume: 750ml
• Light Primer is required on bare or untreated surfaces and is not included
• Suitable for all types of propeller metals and alloys when correctly primed
• Also suitable for epoxy- and glass-fibre-based composites with the specified primer
• Low-friction surface reduces attachment of fouling organisms
• Self-cleaning action increases with propeller movement and vessel speed
• Tiecoat standard shade: Yellow 23410
• Topcoat standard shade: Black 19990
• Tiecoat volume solids: 67%
• Topcoat volume solids: 78 ± 2%
• Tiecoat reference dry film thickness: 70µm
• Topcoat reference dry film thickness: 80µm
• Theoretical spreading rate: 10m²/L for each component
• Calculated theoretical system coverage: approximately 3.75m² per kit
• Apply the supplied coatings by brush or roller
• No thinning permitted for the Tiecoat or Silic One topcoat
• Tool cleaner: Hempel’s Thinner 808, 08081
• Pot life: approximately 60 minutes at 20°C for each supplied coating
• Minimum surface temperature: above 10°C
• Application and curing humidity range: 30–85%
• Minimum immersion time after the final coat: 24 hours at 20°C
• Maximum time before immersion: one month
• Tiecoat Product Data Sheet issued October 2025
• Silic One Product Data Sheet issued November 2025

Frequently Asked Questions

What is included in the Hempel Silic One Propeller Kit?
The kit contains one 375ml tin of Hempel’s Silic One Tiecoat 27450 and one 375ml tin of black Hempel’s Silic One 77450, giving a total supplied volume of 750ml.

Is Hempel’s Light Primer included?
No. Light Primer is not included in this kit. Hempel’s propeller specification requires two coats of Light Primer on a bare or untreated propeller before applying the supplied Tiecoat and Silic One topcoat.

Is Silic One a conventional antifouling paint?
No. It is a biocide-free fouling-release coating. Its silicone and hydrogel surface makes it more difficult for organisms to attach and supports release and self-cleaning during use.

Which propeller materials are compatible?
Hempel states that the propeller system can be used on all types of metals and alloys. Epoxy- and glass-fibre-based composites are also possible when the correct primer is applied first.

Can Silic One be applied directly to bare metal?
No. The bare substrate must be cleaned, mechanically roughened and coated with the specified Hempel Light Primer system. Silic One itself must be applied only over Hempel’s Silic One Tiecoat.

How should an aluminium propeller be cleaned?
Remove existing antifouling and clean with a suitable detergent. When using Hempel’s Pre-Clean on aluminium, Hempel specifies a 1:20 dilution. Rinse with fresh water, allow the surface to dry and prime promptly after abrasion.

What abrasive should be used?
Hempel specifies 40-grit abrasive paper or another mechanical method that creates a clearly perceptible roughness. Abrasive blasting is preferred where appropriate.

How many coats are required for a bare propeller?
The propeller-specific Hempel system comprises two coats of Light Primer, one full coat of Silic One Tiecoat and one full coat of Silic One topcoat.

Can the Tiecoat or topcoat be thinned?
No. Hempel states that thinning is not allowed for either supplied product. Use Hempel’s Thinner 808, product code 08081, for cleaning application tools.

How much area does the kit cover?
Each component has a theoretical spreading rate of 10m²/L. A 375ml tin therefore covers approximately 3.75m² theoretically at the specified film thickness, making the calculated theoretical system coverage approximately 3.75m². Practical coverage will be lower on propellers because of their shape and application losses.

What is the overcoating interval at 20°C?
Apply the second Light Primer coat 4 hours to 30 days after the first. Apply the Tiecoat 2–4 hours after the second primer coat, then apply Silic One 8–48 hours after the Tiecoat.

When can the propeller be immersed?
At 20°C or 30°C, wait at least 24 hours after the final coat. At 10°C, wait at least 36 hours. In all cases, immerse within one month.

What happens if the Tiecoat-to-topcoat interval is exceeded?
Apply a fresh coat of Silic One Tiecoat before continuing with the Silic One topcoat.

Does Silic One self-clean at low speed?
Self-cleaning is most effective at higher speed, but Hempel states that it can also occur at lower speed with constant use.

How should the coated propeller be cleaned?
Use a dense sponge or cloth followed by a fresh-water rinse, or a suitable fresh-water pressure wash. Do not use a hard brush, stiff bristles or similarly aggressive cleaning tools.

Can traditional antifouling be applied over Silic One?
No. Only compatible fouling-release coatings will adhere to Silic One. Remove the silicone system before changing to a traditional antifouling.

How should the products be stored?
Store in original, tightly closed containers at a minimum of 5°C in a dry, shaded, cool and well-ventilated area, protected from direct sunlight, rain, snow, heat and ignition sources.