Print this guide
How to fully varnish bare wood in good condition
Paint Guide AW041
- I am going to work on a surface above the waterline change
- I want to paint my boat change
- I want to do a full paint or repaint change
- I am going to paint my hull / cabin / trims change
- The part I want to paint is wood / plywood change
- The surface is bare change
- I want to use varnish / stain change
- The surface is showing no defects change
Paint job at a glance
- Step 1Sanding bare wood
- Step 2Cleaning bare wood
- Step 3Applying varnish
Here's your custom paint guide
Before any project, take these things into account to get the best results:
- Factor in enough time for each stage of your project so you don't have to rush.
- Always check the weather while planning your project. Temperature, humidity and dew point affect the quality of your work.
- Check you have all the equipment, tools and products you need.
- Ensure you read all the information in the health and safety tab above.
Equipment we recommend for this guide
Equipment List 2
- Paint brushes (suitable size)
- Tack rag or lint free cloth
- Sanding paper 220 - 600 grit (various grades for varnish application)
- Safety shoes
- Face dust masks
- Hand protection (as per product SDS)
- Overalls
- Sanding machine and/or suitable sanding blocks
Equipment List 3
- Eye protection
- Specialized cleaning product
Your health and safety
Your safety is of the utmost importance to us. Ensure that you read and follow all label instructions and the safety datasheet before starting your project. Also:
Ensure the area you are working in is properly ventilated.
Ensure all products are kept out of reach of children during storage and usage.
Ensure solvent fumes and any splashing of material will not affect others nearby.
PPE (Personal Protective Equipment)
Before you begin, always refer to the label and safety datasheet for product specific information. Using the right PPE for your project is important to ensure your safety. You should always check the information from the PPE manufacturer to ensure you use the correct items for your working conditions.
Wear safety glasses at all times to protect your eyes from splashes.
Chemicals can cause skin irritation. Wear overalls and protective gloves to protect your skin and clothing.
To avoid inhalation of dust while sanding; wear a dust mask at all times.
Many products contain either solvents or other chemicals that can build up in confined areas creating a hazard and/or an unpleasant working environment. Wear suitable respiratory protection if ventilation is not sufficient or if required by the safety datasheet to do so.
See the protective equipment overview for further information.
We care deeply about the environment and we want to ensure that our products are disposed of in the correct way. With that in mind, please:
- Always refer to the product label and safety datasheet for any specific instructions.
- Ensure any waste product including cans, rags, brushes, roller sleeves masking tape and paper, gloves and overalls are disposed of according to local regulations.
- Do not allow any waste material such as unused paint to enter any waterways.
- Ensure waste and empty containers are disposed of in accordance with local legislation guidelines and national regulations.
For more information or any special waste regulations, please contact your local waste regulation authority.
Step 1 Sanding bare wood
1.1 Sand
- All wood should be sanded down by hand using 80-120 grit or by using an electric sander. This will open up the grain and help the paint scheme adhere to it.
Show tips from pros
- Always sand along the grain as sanding across it can cause scratches that will show through in the final finish.
- To avoid sanding marks showing through the final paint film, start with a coarser paper and then change to a finer grade. Don’t jump more than 100 grades in one go. This is especially important when painting darker colours, as the sanding marks will show through more easily.
- Be careful that you don’t sand over sealants around the windows or fittings as the sealant can contaminate the surface. Cover these areas with masking tape before sanding.
Show equipment you'll need
- Rubber gloves
- Dust mask
- Sanding paper 80 - 180 grit (various grades for surface preparation)
- Overalls
- Sanding machine and/or suitable sanding blocks
- Eye protection
Step 2 Cleaning bare wood
2.1 Remove particles
- Remove any sanding residues with clean compressed air or vacuum clean for best results.
2.2 Clean surface
- Wipe the surface with a suitable solvent immediately before painting to remove any final particles. It’s important that the solvent has fully evaporated before you apply any paint. You can also use a tack rag.
Show tips from pros
- Oily or acid containing woods such as Teak / Iroko or Oak must be properly degreased.
- The first layer of paint must be quickly applied after the degreasing process, before the wood's natural oil returns to the surface.
- When degreasing with solvent, work with the 2-cloth method: use one cloth soaked with solvent and then wipe straight after with a clean cloth to remove the contamination.
- Use a fast evaporating solvent so it doesn’t remain in the grain.
- Change the cloths regularly to avoid spreading the dirt back to the surface.
Show equipment you'll need
- Extension for cleaning tool
- Sponge and/or cloths
- Vacuum cleaner (or compressed air)
- Rubber gloves
- Tack rag or lint free cloth
- Safety shoes
- Overalls
- Eye protection
- Specialized cleaning product
Step 3 Applying varnish
Varnishes normally don’t need to be stirred but if they do, use a clean wide blade and use a slow stirring lifting action to incorporate any sediment – this may happen with satin or matt finish varnishes.
You don’t need to shake the can to prepare the varnish; this will introduce air and make it difficult to apply.
3.1 Mixing
- If it’s a 2 pack product mix the individual components thoroughly. Add the curing agent to the base (the stated mix ratio must be used), stir and leave the mixed varnish for around 10 minutes to allow bubbles to disperse. Two pack products have a limited pot life when mixed. Refer to label or technical data sheet for further information.
- Decant the varnish you need for each session into a clean plastic, paper, glass or tin container/tray.
- Close your varnish can and put it away to avoid contamination and also to prevent it from ageing prematurely due to solvent loss.
3.2 Application
- For bare wood, the first 1-2 coats are normally thinned (by up to 50%) using a compatible solvent. This will help the varnish to penetrate into the grain providing better adhesion.
- Once these sealing coats have cured, lightly, sand the raised grain using 220 grit paper but try not to break through to the timber on edges.
- When applying varnish, brush it out with firm strokes along and across the grain holding the brush at 90 degrees to the surface.
- Finish by gently stroking the surface with the brush at 45 degrees to flatten out the brush marks and pop any bubbles that might have appeared.
- On vertical surfaces, lay-off with light vertical strokes. This will let any brush marks flow out and create the best possible finish.
3.3 System build
- On exposed exterior surfaces, it is important that the tops of the grain are well protected. To do this you have to fill the grain structure to the tops of the highest grain first before you start counting the number of coats applied.
- Application of 3-4 coats without sanding following the overcoating information on the datasheet or label on the can is a good way to achieve initial film build. Allow these coats to cure/dry and then sand in the direction of the grain with 280-320 grit paper to remove brush marks, dust, runs or any other raised defect.
- During the system build process, only use enough thinner to make application easy.
- The more thinner you put in, the less paint that is applied to the surface and the more coats you will need to put on.
- This process may need to be repeated several times to achieve a suitable varnish layer to protect the wood.
- Once any grain has been filled then apply the number of coats as recommended on the label or technical data sheet.
3.4 Final sanding and application
- Once the grain is completely filled, sand the varnished surface with 400-600 grit in the direction of the grain.
- For the final application, add an additional 5-10% thinner compared with the system build step. This will help to achieve a smoother surface with less brush marks.
- Apply 1-2 final coats of varnish to achieve a smooth finish.
Show tips from pros
Working with a roller:
- Applying paint with a roller is a fast method of covering large/flat areas
- Rollers should be high density closed cell foam types to minimise formation of bubbles that can occur with mohair or large cell foam rollers.
- If rollering with felt or mohair rollers, wrap masking tape around a new roller and then pull off to remove any loose fibres.
- Some rollers may be affected by solvents in the product and can swell during use. When they become too soft to use, or look like they are breaking up, replace them with a new one.
Working with a brush:
- The best brushes to use are well worn ones that have good tapers to their bristles and are soft and clean. If you don’t have any then use the softest tapered bristle brushes you can find.
- You’ll need a range of brush sizes from typically 15mm up to 100mm. The smaller ones are perfect for cutting in around windows and on smaller fiddly pieces.
- Wash your brushes with the thinner and dry them thoroughly before using to avoid contamination.
Other useful tips:
- One important rule to remember is: try not to varnish in direct sunlight.
- Do not leave bare wood exposed for too long as it may absorb moisture from the atmosphere
- If you miss an area, leave the varnish to dry and sand this particular area so it’s smooth around the edges. Then varnish the whole surface as normal.
- Make sure you apply thinner rather than thicker layers of varnish as these will cure and sand better. Thick films can take much longer to dry especially in colder weather.
- Never rely on heavy application of product to disguise any defects. As the varnish cures and shrinks slightly, they may re-appear through the final coats.
- Wear dust and lint-free clothes, not wool clothing or similar. These will contaminate the varnish with fibres and dust.
- To check if there is any dust on the surface run your fingers over it very lightly. If you feel any, either use your fingers to wipe it off, or use a clean dry lint free cloth or a suitable tack rag. Ensure your hand is not greasy when doing this by washing your hand in warm soapy water and drying thoroughly.
- If varnishing outside in an exposed situation, apply when the air temperature is decreasing rather than increasing. If you apply as the temperature is increasing, air in the fibers can expand and create air bubbles in the varnish surface. These can form when it’s too late to remove them with laying-off using a brush. Overall, varnish is absorbed better in decreasing temperatures as the timber provides improved sealing.
- When applying varnish and especially a 2 pack type, work the brush back into the wet product you’ve just applied. Work methodically by varnishing all areas including the edges as you progress so all areas you’ve coated have a good wet edge. As you apply the varnish, solvent will evaporate and the varnish applied will start to become sticky. For a few minutes you can lap new work into the old, but don’t be tempted to go back over an area once it has started to set.
- Sanding between coats will remove product so remember to apply extra coats to allow for this.
Show equipment you'll need
- Paint roller tray
- Paint rollers (suitable sizes and types)
- Paint brushes (suitable size)
- Tack rag or lint free cloth
- Sanding paper 220 - 600 grit (various grades for varnish application)
- Safety shoes
- Face dust masks
- Hand protection (as per product SDS)
- Overalls
- Sanding machine and/or suitable sanding blocks
- Eye protection
We're here to help
We're ready to help. Our friendly help desk is open weekdays 8:00 - 16:30
Call 01489 775062
Send an e-mail to iyp.uk@akzonobel.com
Whether you call or e-mail, please mention your paint guide reference: AW041
Who's painting?
Choose one of the following to tailor the site to your needs
Paint your boat like a pro
Find the best products to keep your boat in great condition
Get all the support you need to paint with confidence
Benefit from our continuous innovation and scientific expertise