Polyurethane is one of the top most durable protective wood finishes, and it’s also easy to apply. They are now available for purchased in an oil-based formula and a water-based formula. Each formula is applied differently and has a different durability level. If a project will endure a lot of damage over time, there aren’t many finishes that are as suitable as applying polyurethane for the final coat.
Is Water-Based Or Oil-Based Polyurethane Better?
Whether a water-based or an oil-based polyurethane is used depends on your project. Water-based polyurethanes are harder to apply and more temperamental than oil-based polyurethanes. With oil-based polyurethanes, a couple applications will suffice to safeguard your project.
Projects coated with oil-based polyurethane take an extended period of time to dry, thus making your finish susceptible to bugs and dust. The oil-based finish is also susceptible to brush marks.
Water-based versions smell less when applying, dry much quicker, and self-levels a bit more than oil based versions. Moreover, the water-based versions have a tendency to lift the wood grain, have a possibility to be temperamental when used in conjunction with stains, and are privy to water marks. A milky-white appearance is common when applying water-based polyurethanes; however, this look should fade as the application dries.
When using polyurethane in a can, never shake it. Instead, stir. You may be wondering why.
Well, if you shake polyurethane in a can, this will prompt many bubbles to be introduced into the product, which will appear on your final finish. Instead of shaking, stir the can of polyurethane thoroughly before using. Be sure to be gentle.
Never work in a dirty and poorly ventilated area with either version. You can use naphtha or mineral spirits to thin the oil based versions; however, this is not a necessity for most applications.
Application Of An Oil-Based Version
A foam brush, a clean cloth, or a brush with fine bristles can be used during an oil-based polyurethane application. Do not use cheap bristle brushes, because these brushes have a tendency to leave behind brush strokes that are obvious.
Foam brushes are my preference, because they are cheap but result in an even finish minus many visible brush strokes. Use a sufficient, but not too thick layer of polyurethane to brush along with the wood grain.
Try not to over brush while making sure to use long strokes. This helps brush away as many bubbles as you can. Within moments, the bubbles that remain will typically disappear.
After 24 hours, the first coat is usually dry. You can then lightly use 320-grit sandpaper against the grain to sand the entire finish. The product will easily sand, so be sure not to damage the stain that is present underneath the polyurethane by sanding through the coating, which is thin. Before the application of a second coat, be sure to remove all of the dust away that was caused by the sanding.
These steps should be repeated until you reached the protection level desired, usually a couple of coats will suffice. Once you apply the final coat, you may opt to use a #0000 steel wool to smooth out the finish to a sheen level that is consistent. For a pretty luster, you can then follow that with applying paste wax.
In the next post we will get even more excellent urethane tips, for both oil and water based polyurethanes. They will really help out with your finishing using this great product!