Modern waterborne finishes give excellent results, but when applying they are less forgiving than solvent finishes, so you have to be more precise in your preparation and techniques. If you continue to do everything exactly the same as when applying solvent finishes, you could end up in trouble.
Here are some tips:
- When storing, do not allow to freeze
- Temperature important when spraying (min temperature is 18°C)
- Filtering important
- Important to apply thin coats, especially first coat/sealing coat
- Scuff sanding and time interval between applying coats is important so good adhesion occurs between coats.
- When applying low sheens (matt and satin) first coat with a sealer or gloss to prevent a cloudy effect.
- When applying on top of an oil or solvent based stain allow a minimum of 1 hour before applying WB finish. (This drying time is for Behlen stains. Always check with the manufacturer of the stains for recommended dry times.)
- When storing, do not allow to freeze.
- Brush application should only be done if the manufacturer suggests doing so.
- Apply a coat as a sealer. Sometimes a separate sealer is available. Usually, waterborne coatings are self sealing.
- High quality natural or synthetic brushes generally give the best results. Discontinue the use of a foam brush if you see bubbles forming in the finish. Do not use
- Sponge blocks for application, as they create more foam and apply too much finish.
- Check with the manufacturer’s instructions for drying times on each product. Also remember that dying between coats is significantly affected by temperature and humidity.
- Sand the seal coat after it dries. All waterborne products raise the grain to some degree. A good sanding of the first coat will eliminate the problem of a rough finish for subsequent coats.
- Do not finish beyond 4 mils thickness.
- If you plan to sand and rub the finish, wait a few days for drying to take place.
- Do not attempt to conduct adhesion tests for about a week after application.
By making some small changes you will get excellent results.