Hempel Profair Epoxy Filler - 1 Litre

Hempel’s Profair 35290 is a lightweight, two-component epoxy filler and fairing compound for glass fibre (GRP), hardwood, steel and other rigid materials. Designed for interior and exterior use above or below the waterline, it mixes 1:1 by volume, can be applied up to 25mm thick without sagging and provides a theoretical spreading rate of 1m²/L at the reference 1,000µm dry film thickness.

Hempel’s Profair combines good adhesion and water resistance with a cured surface that is easy to sand. It is intended for profiling large areas and for detailed fairing where strength and flexibility are required. The product is supplied as Base 35299 and Curing Agent 98290, with equal volumes mixed immediately before use.

The standard mixed shade is Light Blue 30540. Hempel lists 98 ± 2% volume solids, a specific gravity of 0.8kg/L and a semi-gloss finish before sanding and overcoating.

Intended Applications and Compatibility

Profair is suitable for correctly prepared glass fibre, hardwood, steel and other rigid materials. It can be used on interior and exterior surfaces above and below the waterline.

For uncoated surfaces, sand and remove all dust, then apply one to two coats of the specified Hempel primer before filling. Hempel’s Light Primer is the recommended previous coat and subsequent coat. Once the filler is dry, overcoat with two coats of the recommended primer. Do not apply the finishing topcoat directly over Profair.

Mixing and Application

Mix Base 35299 and Curing Agent 98290 in a 1:1 ratio by volume immediately before use. Blend equal parts until a uniform colour is obtained and avoid introducing air bubbles. Do not add thinner.

Apply with a putty knife. The surface temperature must remain above 10°C during application and curing, and relative humidity must remain below 85% during drying and curing. At a product temperature of 10°C, the stated pot life is two hours.

Profair can be built to a maximum thickness of 25mm without sagging. Shape and fair the product while it is still soft enough to retain a fingerprint. After curing, sand the filler smooth and remove all dust before applying the specified primer system.

For cleaning, Hempel specifies Hempel’s Thinner 845, product code 08451, and Hempel’s Degreaser 99611. These products are cleaners only; Profair must not be thinned.

Drying and Overcoating

At the reference 1,000µm dry film thickness, Profair is touch dry after approximately 24 hours at 10°C or 12 hours at 20°C. At 20°C, it is ready to sand after approximately 24 hours. Hempel does not state a ready-to-sand time at 10°C in the current Product Data Sheet.

Full cure is reached after approximately 14 days at 10°C or seven days at 20°C. For another coat of Profair, the minimum overcoating interval is 60 hours at 10°C or 24 hours at 20°C, with no stated maximum interval for either atmospheric or immersion service.

Where the surface has been contaminated before overcoating, remove oils and pollutants with a suitable detergent, rinse with fresh water and allow the surface to dry. Lightly abrade and remove all dust before continuing. Maintain sufficient ventilation and prevent condensation throughout application, drying and curing.

Key Features

• Official Hempel product code 35290
• Lightweight two-component epoxy filler
• Base 35299 and Curing Agent 98290
• 1:1 mixing ratio by volume
• Good adhesion and water resistance
• Easy to sand when fully cured
• Suitable for glass fibre (GRP), hardwood and steel
• Suitable for other correctly prepared rigid materials
• For interior and exterior use
• Suitable above and below the waterline
• For large-area profiling and detailed fairing
• Suitable where strength and flexibility are required in the fairing system
• Maximum non-sag application thickness: 25mm
• Standard shade: Light Blue 30540
• Volume solids: 98 ± 2%
• Specific gravity: 0.8kg/L
• Reference dry film thickness: 1,000µm
• Reference wet film thickness: 1,019µm
• Theoretical spreading rate: 1m²/L
• Apply with a putty knife
• No thinning permitted
• Pot life: two hours at a product temperature of 10°C
• Minimum application and curing temperature: above 10°C
• Maximum relative humidity: below 85%
• Touch dry in approximately 12 hours at 20°C
• Ready to sand in approximately 24 hours at 20°C
• Fully cured in approximately seven days at 20°C
• Recommended previous and subsequent coat: Hempel’s Light Primer
• Mixed-product flash point: 94°C
• EU VOC content of mixed product: 19g/L
• Base and curing-agent shelf life: 24 months at 25°C in original unopened containers
• Listed UK pack size: 1L

Frequently Asked Questions

What is Hempel’s Profair 35290 used for?
It is used as an epoxy filler and fairing compound for profiling large areas and for detailed fairing on suitable rigid marine substrates.

Which materials can Hempel Profair be used on?
Hempel specifies glass fibre, hardwood, steel and other rigid materials. Each substrate must be correctly prepared and primed as required.

Can Hempel Profair be used below the waterline?
Yes. It is suitable for interior and exterior use both above and below the waterline.

Is Hempel Profair a structural repair resin?
Hempel describes Profair as a filler and fairing compound, including for detailed fairing where strength and flexibility are required. The Product Data Sheet does not classify it as a structural repair resin, so structural repairs should follow an approved repair specification.

Can it be applied directly to bare GRP, hardwood or steel?
Hempel instructs users to sand uncoated surfaces, remove all dust and apply one to two coats of the specified Hempel primer before filling. Hempel’s Light Primer is the recommended previous coat.

What is the mixing ratio?
Mix Base 35299 and Curing Agent 98290 in equal parts, using a 1:1 ratio by volume. Mix until the colour is uniform and avoid introducing air bubbles.

What is the pot life?
The stated pot life is two hours at a product temperature of 10°C. The current Product Data Sheet does not provide a pot-life figure at 20°C.

How thick can Hempel Profair be applied?
It can be applied up to 25mm thick without sagging. The reference dry film thickness used for Hempel’s coverage and drying data is 1,000µm, or 1mm.

How is Hempel Profair applied?
Apply it with a putty knife. Fair and shape the material while it is still soft enough to retain a fingerprint, then sand smooth after curing.

Can Hempel Profair be thinned?
No. Hempel states that no thinning is permitted and that thinner must not be used in conjunction with the product.

Which cleaner should be used?
Hempel lists Hempel’s Thinner 845, product code 08451, and Hempel’s Degreaser 99611 as cleaners.

How much area does one litre cover?
The theoretical spreading rate is 1m²/L at the reference 1,000µm dry film thickness. If a different film thickness is specified, the spreading rate, drying and curing times and overcoating interval will change.

How long does Hempel Profair take to dry?
At the reference film thickness, it is touch dry after approximately 24 hours at 10°C or 12 hours at 20°C. At 20°C, it is ready to sand after approximately 24 hours.

How long does it take to fully cure?
Full cure takes approximately 14 days at 10°C or seven days at 20°C.

Can a topcoat be applied directly over Profair?
No. Hempel instructs users to overcoat the dry filler with two coats of the recommended Hempel primer. Finishing topcoats should not be applied directly to Profair.

What application conditions are required?
The surface temperature must be above 10°C during application and curing. Relative humidity must remain below 85%, sufficient ventilation must be maintained and condensation must be avoided.

How should Hempel Profair be stored?
Store both components in original, tightly closed containers at a minimum of 5°C in a dry, shaded, cool and well-ventilated location. Protect the containers from direct sunlight, rain, snow, heat and ignition sources. The curing agent is moisture-sensitive.