As a woodworker, a significant aspect of your work revolves around the various types of wood finishes and how to use them. One of the most popular finishes is polyurethane varnish, which we commonly call polyurethane and, most often, only “poly.” This wood finish is an extremely versatile type of finish, and we use it for all kinds of wood and non-wood surfaces.
There are different aspects to poly, and accordingly, people have many questions about this wood finish – how to use it, the properties of poly, and so on. We have identified the most typical questions regarding poly, particularly wipe-on poly, and provide you answers to those questions in this post.
Wipe-On Poly FAQs
We wipe on this wood finish onto the wood surface rather than use a paintbrush or spray machine. It gives the surface a smooth “hand-rubbed” finish, thin, durable, and pleasant-looking. There are a few things that you need to consider, and in line with so many questions being asked about wipe-on Poly, here are some of the answers to the best questions:
What is Wipe-On Polyurethane?
Wipe-on polyurethane is an oil-based polyurethane that we also call “wipe-on poly.” It is a popular type of wood finish because it imparts durability to the wood surface and enhances its looks. Wipe-on poly is a preferred type of wood finish because of the simplicity of application where instead of a brush, you only need a waste rag with which to apply the finish.
How do You Mix Wipe-on Poly?
Wipe-on poly comes already thinned down with mineral spirits. You can buy it in this premixed form. If not, you can mix it up yourself. Whatever type of wipe-on poly you get, a good mix is 80% polyurethane and 20% mineral spirits. However, this is just an approximation. Mix enough mineral spirits into the poly to make it a consistency that can be easily absorbed by a cloth and wiped onto a wooden surface.
How do you Wipe on Poly?
Applying wipe-on poly is quite an easy process. A best practice is not to shake the can, but open it gently and stir it slowly, which prevents air bubbles from forming. Now, empty a small quantity of the liquid into a plastic bowl or old food container. Add mineral spirits until you get the desired consistency. Now, dip the rag in the mix and spread it evenly across the surface of the wood. Take care to apply only a bit at a time and wipe off the excess.
Is Wipe-On Poly Waterproof?
Even if you cover the entire surface evenly with multiple coats, the wood will not become waterproof. After the poly has completely dried and cured, the wood will expand and contract due to its moisture content. This expansion and contraction allow moisture to enter the wood. At best, wipe-on poly can make it water-resistant.
Can you Apply Poly Over Paint?
Applying poly over an existing coat of paint is possible if the painted surface is dry, oil-free, and free from debris. Typically, you should only need a couple of coats of wipe-on poly on an already-painted surface. After applying the finish, allow the coating to dry for 24 hours before touching the surface.
Can You Store Unused Poly?
After opening a sealed can of wipe-on poly, you can store it in an air-tight container even if you mix it with mineral spirits. The key is not to allow air to enter the container. Try to consume the remaining liquid within a month. The more frequently you open the box, the more the chance of the polyurethane drying up.
What is the Best Cloth for Wipe-On Polyurethane?
Any old cotton garment will make a suitable applicator for wipe-on poly as long as it is clean and lint-free and loose strands or threads. It is preferable using a white cloth because you can see dust particles and solid contaminants easily. Ensure that the surface of your rag is clean and only contains polyurethane before you start applying it to the wood. If you wish you can also purchase a specially made microfiber cloth like this one – although it’s probably an unnecessary expense – unless you have an important project or just prefer to use something new and clean vs repurposing old clothes or kitchen towels.
How Long to Wait Between Coats While Applying Wipe-On Poly?
It would help if you allowed sufficient time for a coating of wipe-on poly to dry before applying the next coat. Wait for a minimum of two to three hours before applying the next coat. Or, if you have the time, you can even wait overnight. The drying time also depends on atmospheric conditions. The finish will dry faster in hot, dry weather and will take a longer time to dry in a humid environment. You risk causing blotches if you start applying the next coat before the previous one is thoroughly dry.
How to Safely Dispose of Rags After Applying Wipe-On Poly?
Rags soaked in poly are a fire hazard. As they dried, there were cases where rags heated up, smoldered, and caught fire. The safest procedure is to spread them out in the open, separately weighted down with a stone on a non-flammable surface overnight. Once the rags are dried stiff, they do not pose a fire hazard anymore, and you can throw them away in the trash.
How to Prep a Wooden Surface Before Applying Wipe-On Poly?
The final result of your finish depends a lot on how you prep the wood’s surface before applying the finish. Use 220-grit sandpaper to make the surface smooth. You may need to use a wood grain filler for woods like oak, walnut, or ash with open-grain wood patterns.
Once you have finished the sanding, make sure to remove the dust with a dry cloth or vacuum cleaner. You can repeat this process after each successive coat. However, you will have to use a finer grit of sandpaper while sanding a newly-applied coat of wipe-on poly.
How Can You Renovate Old Furniture with Wipe-On Poly?
Over the years, woodwork tends to lose its luster and begins to look old and dull. You can bring back life into your old furniture with a couple of coats of wipe-on poly. First, you should thoroughly wash the surface of the wood with soap and water to remove the grime and oil.
Next, rub the surface with 220-grit sandpaper, and wipe off or vacuum the dust. Apply a couple of coats of wipe-on poly to the woodwork. Ensure that the first coat dries completely before you apply the second one. You can rub the surface of the wood with 0000 steel wood for a better binding before applying the second coat.
How do you remove polyurethane from a Stained Surface?
You can strip poly from a stained wood surface without removing the stain. For this, you can make a homemade chemical stripper. Mix equal parts of lacquer and thinner in a bowl. Apply the mixture with a paintbrush. After 10 seconds, use a piece of 0000 steel wool to remove the stripper and the now-dissolved poly layer. Wash the surface lightly with warm water. You will have now removed the layer of polyurethane without disturbing the stain on the wood’s surface.
We browsed through numerous websites and blogs to feature the commonest-asked questions regarding wipe-on poly and their answers. Although you may find much information about this type of wood finish, you may not see all the answers to your questions in one place. Hence, we felt that this post of wipe-on FAQs to be quite appropriate.
Although we have covered as many questions as possible, there may still be a few questions you may have. Please post your questions if any, in the comments section below, and we will be glad to respond.