Hempel Light Primer – Complete Guide to Epoxy Painting Your Boat Hull
Ari USA
Hempel's Light Primer is a high-quality two-component, solvent-based epoxy primer that effectively protects boat surfaces against corrosion and osmosis. It is suitable for use above and below the waterline on fiberglass, steel, aluminum, and plywood surfaces.
When you want to ensure that your boat hull is protected in terms of both watertightness and adhesion, Hempel Light Primer is an excellent choice. This two-component epoxy primer acts as both an osmosis and corrosion protector, and is suitable for use both above and below the waterline on fiberglass, aluminum, steel, and wooden surfaces.
Why choose Hempel Light Primer?
- Corrosion protection: Forms a hard, wear-resistant surface that effectively protects against water and fuels.
- Osmosis protection: Prevents osmotic blistering in fiberglass boats, extending the boat's lifespan.
- Versatility: Suitable for various materials and for use both above and below the waterline.
Hempel Light Primer Quick Guide
- Surface pre-treatment: Ensure the surface is clean, dry, and grease-free. Remove oil and grease with a suitable cleaning agent, such as Hempel’s Degreaser. Sand the surface to roughen if necessary.
- Mixing: Carefully mix the two components of the primer according to the manufacturer's instructions.
- Application: Apply the paint with a brush, roller, or spray gun. The recommended dry film thickness is 60–100 microns, depending on the application method. Wet film: 120–200 microns.
- Drying time: Allow the paint coat to dry for at least 4 hours at 20°C before applying the next coat.
- Overcoating: The primer can be overcoated with, for example, Hempel's Underwater Primer or directly with antifouling paint according to the manufacturer's recommendations.
- Coverage: approx. 8.2 m²/l
Hempel Light Primer treatment
1. Before painting – surface preparation
Fiberglass / Gelcoat:
- Wash the surface with Hempel’s Degreaser (99611).
- Lightly sand with sandpaper (grit approx. 180).
- Remove dust.
Steel:
- Remove salts, oil, and grease (pressure wash with fresh water).
- Sandblast (min. Sa 2½) or mechanically grind.
Aluminum:
- Wash with diluted Hempel’s PreClean (1:20).
- Wipe with pressure washer and roughen the surface with non-metallic sandpaper.
Plywood:
- Sand and remove dust.
- Saturate surfaces with Hempel’s Sealer.
Previously painted surfaces:
- Degrease and remove impurities.
- Sand or sandblast damaged areas.
- Do not use Hempel’s Light Primer over paints other than 2K paints.
2. Paint mixing
- Mix base 45559 and hardener 95360 in a ratio of 2:1 by volume.
- Mix thoroughly and wait a few minutes for air bubbles to dissipate.
3. Painting execution
Tools and thinning:
- Brush, roller or pad: thinner Hempel’s Thinner 845, max. 20%
- Spray gun: max. 20% thinning (if needed up to 40%)
- High-pressure spray gun: max. 10%, nozzle size 0.017–0.021″, pressure 175 bar.
Recommended film thickness:
- Dry: 60–100 microns
- Wet film: 120–200 microns
- Coverage: approx. 8.2 m²/l
4. Drying times (20°C)
Low temperatures prolong drying time. For example, at 10°C, the drying time doubles.
| Drying at 20°C | Time |
|---|---|
| Touch dry | 3 h |
| Hard dry | 6 h |
| Fully cured | 7 days |
| Sandable | 48 h |
5. Overcoating with Light Primer
What is the minimum/maximum drying time for Light Primer before overcoating at 20°C? Low temperatures prolong drying time. For example, at 10°C, the drying time doubles.
| Next product | Min. time 20°C | Max. time 20°C |
|---|---|---|
| Light Primer | 4 h | 30 days |
| Underwater Primer | 2 h (tacky) | 4 h |
| Silic One Tiecoat | 2 h | 4 h |
| Polygloss / Polyenamel | 7 h | 72 h |
| Epoxy Filler / Profair | 4 h | 30 days |
| Non-Slip Deck Coating | 2 days (sanding recommended) | 4 days. |
Note: If the maximum overcoating time is exceeded, the surface must always be lightly sanded to ensure adhesion.
6. Usage conditions
- Surface temperature: above +10°C
- Relative humidity: below 85%
- Good ventilation is important during drying.
7. Safety
- Avoid skin contact and inhalation of vapors.
- Use protective equipment and ensure ventilation.
- Always read the safety data sheet before use.
8. Storage
- Shelf life 36 months (in unopened packaging).
- Protect from sunlight, moisture, and frost.
- Store below +35°C.
Hempel Light Primer is an effective and versatile epoxy primer that ensures durable and long-lasting surface protection. When applied correctly, it forms a reliable base for subsequent paints and antifouling coatings.
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Learn more about Light Primer.