Hempel Primer Undercoat

Hempel’s Primer Undercoat 13201 is a quick-drying, high-opacity, single-component marine primer and undercoat for glass fibre (GRP), wood and steel above the waterline. In standard White 10000, it has a theoretical spreading rate of 12m²/L at a 40µm dry film thickness and is touch dry in approximately three hours at 20°C.

Product Overview

Hempel’s Primer Undercoat provides durability and surface stability before overcoating with compatible single-component topcoats. It is suitable for interior and exterior marine surfaces above the waterline and can be used as a primer on correctly prepared glass fibre, wood and steel, including bare steel.

Recommended subsequent coats are Hempel’s Brilliant Gloss, Hempel’s Multicoat, Hempel’s Bilge & Locker Paint and Hempel’s Non-Slip Deck Coating. For new wood, Hempel’s Wood Impreg is the recommended previous treatment.

Surface Preparation and Application

Remove oil, grease and other contaminants with a suitable detergent. Sand uncoated surfaces and remove all dust. New wood should be dry and clean, saturated with a suitable wood treatment and allowed to dry. Steel should be fresh-water cleaned to remove salts and contaminants, then abrasive blasted or power-tool cleaned to remove rust and loose material. Previously coated surfaces must be abraded, cleaned and dried; spot repairs should be sanded to produce a uniform surface profile.

Stir well before use. Apply by brush, roller, paint pad or airless spray using Hempel’s Thinner 811, product code 08111, as the specified thinner and equipment cleaner. Keep thinning to an absolute minimum. Hempel’s application remarks allow up to 5% thinner where needed, while the first coat on a porous surface may be thinned by up to 10%. Apply two full coats undiluted after priming a porous surface; apply two full coats undiluted to previously coated surfaces. Sanding between coats is recommended where a smoother finish is required, with all dust removed before recoating.

The application-method table lists maximum thinning limits of 10% for brush, roller and paint-pad application and 15% for airless spray. Contact Hempel for spray parameters. Apply only to a clean, dry surface at least 3°C above the dew point, keep relative humidity below 85% during drying and curing, and maintain adequate ventilation.

Drying and Overcoating

At a 40µm dry film thickness, Hempel’s Primer Undercoat is touch dry in approximately three hours at 20°C or six hours at 10°C. It is ready to sand after approximately 24 hours at 20°C.

At 20°C, the overcoating interval is 4–72 hours for another coat of Hempel’s Primer Undercoat, Hempel’s Brilliant Gloss or Hempel’s Non-Slip Deck Coating. For Hempel’s Multicoat or Hempel’s Bilge & Locker Paint, the interval is 24 hours to seven days. At 10°C, the corresponding intervals are 8 hours to 5½ days and 48 hours to 13 days. If the maximum interval is exceeded, roughen and clean the surface before recoating.

Key Features

• Official Hempel product code 13201
• Quick-drying, high-opacity primer and undercoat
• Single-component coating
• Suitable for glass fibre (GRP), wood and steel
• For interior and exterior use above the waterline
• Standard shade White 10000
• Listed pack sizes: 750ml and 2.5L
• Volume solids: 49 ± 2%
• Specific gravity: 1.3kg/L
• Reference dry film thickness: 40µm
• Recommended wet film thickness: 82µm
• Theoretical spreading rate: 12m²/L
• Apply by brush, roller, paint pad or airless spray
• Use Hempel’s Thinner 811, product code 08111
• Touch dry in approximately three hours at 20°C
• Ready to sand in approximately 24 hours at 20°C
• Compatible with Hempel’s Brilliant Gloss
• Compatible with Hempel’s Multicoat
• Compatible with Hempel’s Bilge & Locker Paint
• Compatible with Hempel’s Non-Slip Deck Coating
• EU VOC content: 391g/L; value may vary by shade
• Flash point: 40°C
• Shelf life: 60 months at 25°C in original unopened containers

Frequently Asked Questions

What is Hempel’s Primer Undercoat 13201 used for?
It is used as a single-component primer and undercoat on glass fibre, wood and steel before applying compatible above-waterline Hempel topcoats.

Which surfaces are compatible?
Hempel specifies glass fibre, wood and steel. The surface must be correctly prepared, clean and dry before application.

Can it be used below the waterline?
No. Hempel specifies this product for interior and exterior use above the waterline.

Can it be applied to bare steel?
Yes, for above-waterline use after removing salts, rust, loose material and dust by the preparation methods stated in Hempel’s Product Data Sheet.

How should new wood be prepared?
New wood should be dry and clean, saturated with a suitable wood treatment and allowed to dry. Hempel lists Hempel’s Wood Impreg as the recommended previous treatment for new wood.

How many coats should be applied?
For porous surfaces, prime with a first coat thinned by no more than 10%, then apply two full coats undiluted. On previously coated surfaces, apply two full coats undiluted.

How can Hempel’s Primer Undercoat be applied?
It may be applied by brush, roller, paint pad or airless spray. Contact Hempel for airless-spray parameters.

Which thinner should be used?
Use Hempel’s Thinner 811, product code 08111, for thinning and equipment cleaning. Keep thinning to a minimum. Hempel allows up to 5% where needed and up to 10% for the first coat on a porous surface; the method table lists absolute maxima of 10% for brush, roller and paint pad and 15% for airless spray.

How much area does one litre cover?
The theoretical spreading rate is 12m²/L at the recommended 40µm dry film thickness. Practical coverage will be lower where application losses or an uneven surface increase paint consumption.

How long does it take to dry?
It is touch dry in approximately three hours at 20°C or six hours at 10°C. At 20°C, it is ready to sand after approximately 24 hours.

When can it be overcoated?
At 20°C, overcoat with Hempel’s Brilliant Gloss, Hempel’s Non-Slip Deck Coating or another coat of Primer Undercoat after 4–72 hours. Overcoat with Hempel’s Multicoat or Hempel’s Bilge & Locker Paint after 24 hours to seven days. Longer intervals apply at 10°C.

Which Hempel topcoats are compatible?
Hempel lists Hempel’s Brilliant Gloss, Hempel’s Multicoat, Hempel’s Bilge & Locker Paint and Hempel’s Non-Slip Deck Coating as recommended subsequent coats.

What pack sizes are listed by Hempel?
Hempel Yacht lists 750ml and 2.5L pack sizes for product code 13201.

How should the product be stored?
Store it at a minimum of 5°C in a dry, shaded, cool and well-ventilated location, away from direct sunlight, rain, snow, heat and ignition sources. Keep the container tightly closed. Shelf life is 60 months at 25°C in the original unopened container.