Hempel Prop Propeller Primer Spray - 500ml

Hempel’s Prop Primer 101EX is a fast-drying, anti-corrosive aerosol primer and tiecoat for propellers, outdrives, chock marks and small repair areas on yachts. Supplied in a 500ml spray can in Grey 11320, it adheres to glass fibre (GRP), steel and other metals and provides a flat base before compatible antifouling. The current theoretical spreading rate is 6.6m²/L at a 30µm dry film thickness, equivalent to approximately 3.3m² per 500ml can under theoretical conditions.

Hempel’s Prop Primer is formulated as both an anti-corrosive primer and a tiecoat between correctly prepared substrates and a compatible antifouling system. Hempel specifies it for propellers and outdrives, as well as chock marks and small patches on yachts. It is overcoatable with the most common generic paint types, with Hempel’s Ecopower Prop listed as the recommended subsequent coating.

The aerosol format is intended for controlled application on small, shaped and difficult-to-reach components. Its flat finish helps produce a uniform base for the selected antifouling system. The product has 20 ± 2% volume solids, a specific gravity of 1kg/L and a reference dry film thickness of 30µm.

Suitable Surfaces and Applications

• Glass fibre (GRP)
• Steel
• Other correctly prepared metals
• Propellers
• Outdrives
• Chock marks
• Small repair patches on yachts

The current Hempel Product Data Sheet specifies propellers and outdrives. It does not describe Prop Primer as a general-purpose coating for an entire outboard engine, so suitability for a particular outboard component should be confirmed before application.

Surface Preparation

Remove oil, grease and other contaminants with a suitable detergent. On uncoated surfaces, roughen the substrate to improve adhesion, then remove all dust and loose material. For maintenance and repair, remove old antifouling, primer and loose matter. The final surface must be clean and dry before spraying.

Mask surrounding areas and all anodes before application, as required by Hempel.

Application

Shake the aerosol thoroughly before use and periodically during spraying. Hold the can 20–30cm from the surface and apply one light layer at a time until a smooth, uniform coating is obtained. Aerosol application may produce a lower film thickness per coat than other methods, so several coats may be required to reach the specified 30µm dry film thickness. Avoid excessive film build.

After spraying, invert the can and spray briefly to clear the nozzle. Hempel’s Thinner 845, product code 08451, is the specified cleaner. No separate thinning parameter applies to the aerosol spray can.

Apply only to a clean, dry surface at least 3°C above the dew point. Relative humidity must remain below 85% during drying and curing. Maintain sufficient ventilation and prevent condensation on the freshly applied coating.

Drying and Overcoating

At the reference 30µm dry film thickness, Hempel’s Prop Primer is touch dry in approximately 40 minutes at 10°C or 20 minutes at 20°C.

At 20°C, the stated immersion-service overcoating interval is 30 minutes to three hours for another coat of Hempel’s Prop Primer and for Hempel’s Ecopower Prop 7446X. Hempel’s project-specific specification takes precedence over the general interval. Overcoat with the chosen compatible antifouling within the applicable coating-system window.

Key Features

• Official Hempel product code 101EX
• 500ml aerosol spray can
• Anti-corrosive primer and tiecoat
• Fast-drying formulation
• Good adhesion to glass fibre, steel and other metals
• Recommended before antifouling on propellers and outdrives
• Suitable for chock marks and small yacht repair patches
• Overcoatable with most common generic paint types
• Recommended subsequent coat: Hempel’s Ecopower Prop 7446X
• Standard shade: Grey 11320
• Flat finish
• Volume solids: 20 ± 2%
• Specific gravity: 1kg/L
• Reference dry film thickness: 30µm
• Recommended wet film thickness: 152µm
• Theoretical spreading rate: 6.6m²/L
• Approximate theoretical coverage per 500ml can: 3.3m²
• Spray distance: 20–30cm
• Touch dry in approximately 20 minutes at 20°C
• Touch dry in approximately 40 minutes at 10°C
• Overcoating interval at 20°C: 30 minutes to three hours
• Specified cleaner: Hempel’s Thinner 845, 08451
• Flash point: 25°C
• EU VOC content: 774g/L
• Minimum storage temperature: 5°C

Frequently Asked Questions

What is Hempel’s Prop Primer 101EX used for?
It is used as an anti-corrosive primer and tiecoat before antifouling on propellers and outdrives. Hempel also specifies it for chock marks and small repair patches on yachts.

Which materials can it be applied to?
Hempel specifies good adhesion to glass fibre, steel and other metals. Every substrate must be correctly cleaned, roughened where required and free from dust and loose material.

Can it be sprayed over an entire outboard engine?
The current Hempel Product Data Sheet specifies propellers and outdrives rather than complete outboard engines. Confirm compatibility before applying it to a specific outboard component, particularly where heat, electrical parts, seals or manufacturer coatings are involved.

Is Hempel Prop Primer an antifouling?
No. It is a primer and tiecoat used before a compatible antifouling coating. Hempel’s Ecopower Prop 7446X is the recommended subsequent product.

What colour and finish is it?
The current Product Data Sheet lists Grey 11320, described as Pebble Grey or Light Grey, with a flat finish.

How much area does one can cover?
The current theoretical spreading rate is 6.6m²/L at 30µm dry film thickness. A 500ml can therefore provides approximately 3.3m² of theoretical coverage. Practical coverage will be lower where overspray, surface shape and application losses increase consumption.

Why does the supplied product information state 3.5m²/L?
The supplied figure differs from Hempel’s October 2025 Product Data Sheet, which lists 6.6m²/L at 30µm dry film thickness. The current Hempel figure should be used for specification purposes.

How should the surface be prepared?
Remove oil, grease and contaminants with a suitable detergent. Roughen uncoated surfaces for optimum adhesion and remove dust and loose material. For maintenance, remove old antifouling, primer and loose matter. Apply only when the surface is clean and dry.

How should the aerosol be applied?
Shake well, hold the can 20–30cm from the surface and apply one light layer at a time until a smooth, uniform finish is obtained. Shake occasionally during use and apply several coats where required to reach the specified film thickness.

Should anodes be masked?
Yes. Hempel instructs users to mask other areas, including anodes, before application.

How long does Hempel Prop Primer take to dry?
It is touch dry in approximately 40 minutes at 10°C or 20 minutes at 20°C at the reference 30µm dry film thickness.

When can it be overcoated?
At 20°C, the stated interval is 30 minutes to three hours for another coat of Prop Primer or Hempel’s Ecopower Prop 7446X. Follow the coating-system specification supplied for the project.

Which cleaner should be used?
Hempel specifies Hempel’s Thinner 845, product code 08451, as the cleaner. After use, invert the aerosol and spray briefly to clear the nozzle.

What application conditions are required?
The surface must be clean and dry and at least 3°C above the dew point. Relative humidity must remain below 85%, and sufficient ventilation must be maintained during application, drying and curing.

How should the aerosol be stored?
Store at a minimum of 5°C in a dry, shaded, cool and well-ventilated place, away from direct sunlight, rain, snow, heat and ignition sources. Keep the container tightly closed and follow the label and Safety Data Sheet.