How many coats of oil based polyurethane do I need?
We recommend at least 2 coats of oil based polyurethane + a lacquer sealer coat as a minimum for hardwood flooring. Extra coats = extra protection, but only one coat of oil based polyurethane may be applied per day, as it needs 24 hours to dry before applying another coat.
2 Answers. This should be ok if you gave the stain 3-4 days to properly dry out. You'll want the oil-based drying agent to completely vaporize from the stain before applying the water-based finish. You may apply the Minwax Water Based Polyurethane over a fully cured Minwax Wood Finish Stain (oil-based).
- Most stains should be sealed to prevent bleeding. After smoothing the stained wood, apply a sealer coat of thinned shellac, sanding sealer, or other appropriate sealer. Do not use shellac with NGR or water-base stains. If you plan to finish the piece with polyurethane, make sure the sealer is compatible.
- It is possible to paint over surfaces that were stained using oil-based products, but you must do the required preparation work first if you don't want to do repairs later. Stain contains paint-repelling contaminants that you must remove before you can apply paint, to ensure that the paint adheres to the surface.
- Polyurethane is a clear varnish that dries to a hard, solid finish. It protects your wooden surfaces from scratches and prevents paint from peeling, and it's easy to clean. Polyurethane can crack and bubble if it is exposed to too much sunlight, so it isn't suitable for outdoor surfaces.
Although polyurethane gives natural wood floors a beautiful, long-lasting sheen, it is also a toxic chemical and should be used with caution. Water-based polyurethane costs twice as much as its oil-based counterpart, but it is slightly less toxic and has less of an odor.
- Actually, well-manufactured polyurethane is no danger at all. Its dangerous components are rendered inert or non-toxic if successfully bonded. One main ingredient, the cause of polyurethane dangers is isocyanates.
- The only way to make wood waterproof is to burn it. Seriously, polyurethanes will help make wood water-resistant but not waterproof. It will slow down, but not stop, water intrusion. Nothing stops water intrusion into wood, or totally prevents wood respiration.
- Recoat within 2 hours. If unable to do so, wait a minimum of 72 hours, then lightly sand and recoat. Apply at least three coats on unfinished wood and two coats on surfaces already finished. After final coat, allow 24 hours before normal use.
Updated: 23rd October 2018