One of the most common choices for lacquer is polyurethane. There are various PU lacquer benefits, but you can just buy it and apply it to any surface you like. Anything you want to coat needs to be properly prepared first so that there are no issues.
In this home DIY guide, we’ll cover how to prepare a surface for PU lacquer application. Keep reading for more.
Surface Preparation
Start by cleaning the surface you want to coat. This means removing dust, oil, and any other contaminants that may interfere with the adhesion of the primer/sealer.
Bear in mind that substrate and air temperature should not be lower than 50°C or higher than 380°C. Relative humidity should also be below 85%.
Sand the surface with 180 – 220 grit sandpaper and remove any dust and powder. If the wood is old and/or painted you’ll need to clean it with a suitable cleaning agent, solvent, or paint remover.
Finally, clean the surface with air pressure or a vacuum cleaner. This will remove any final contaminants.
Staining
The stain you need will vary depending on the application system and the nature of the substrate to be stained. The final shade will depend on:
- Thinning ratio
- Addition of binders
- Application system
- Nature of the substrates
- Type of sanding operation carried out on the substrate
- Quantity applied
- Chemical nature of coatings applied on the stain
Apply the required coat of Dyes Stain (diluted either with water or thinner). The colour strength will depend on how many coats of stain are applied.
Hand Application
You can apply the stain by hand with a clean, soft, lint-free, white cloth. Spray application and dipping are also possible. Avoid using coloured cloth, as the dyes used to manufacture cloths can bleed into the stain and cause discolouration.
The stain should be applied wet to the whole surface and then cleaned off along the grain. Failure to wet the whole surface can result in uneven stain penetration. This can lead to patchy drying and unevenness of colour.
Leave the stain for the recommended drying time before applying the first coat of sealer. If a sufficient depth of colour can’t be obtained from the staining operation, a spray colour should be incorporated into the finishing system.
Spray Application
Stains can be applied by spray and wiped off with a clean, lint-free white cloth. Wiping off will make the colour more even while highlighting the grain definition and the timber’s natural figuring.
Timber can also be spray stained by dry spraying, but care must be taken to apply an even coat. The gun strokes should follow the grain of the timber. Thinning the stain with 50% methylated spirits will help control the spray staining operation.
Dip Application
Dip application is another option, but it is advisable to wipe off afterwards to achieve an even degree of staining and grain definition enhancement. When solvent-based stains are applied by dipping, the solvent constantly evaporates and must be frequently reintegrated. Not doing this will result in a darker colour.
When water-based stains are kept in a dipping tank for too long, the stain may rot. This is because bacteria can enter the system in several ways. To avoid rotting, you should use potable water for thinning and make sure the dipping tank is kept clean so that there’s no dirt or wood dust.
Priming
Apply 1-2 coats of PU Sealer Clear or PU Primer White with recommended PU Thinner at the dilution rate of 120-150 g/m2 and let it dry. Follow this by applying a suitable putty filler to fill up any holes and uneven surfaces.
Sand the primed surface with 240–360 grit sandpaper. Apply another coat of sealer and sand it with 400-600 grit sandpaper prior to top coating to achieve a smoother finish.
Top Coating
On a well-prepared surface, the stained substrate (after sanding) must be rectified prior to the application of 1-2 coats of PU Lacquer Clear or PU Pigmented Lacquer (Gloss/Semigloss/Matt) at the rate of 120-150 g/m2.
One coat may be sufficient for an ordinary finish, but one additional coat can be applied wet on wet if necessary. Light sanding with 600-800 grit sandpaper is recommended before subsequent coats when the recoating time exceeds 3 hours.
Your PU Lacquer
Using the right PU Lacquer can help give your furniture the perfect finish. At Mas Paints, we have a range of paints, stains, dyes, and more. Click here to see what we have to offer.