Polyurethane
From Cornhole Wiki
Adding a clear finish to a set of cornhole boards is common practice. While most people will use a water based polycrylic, many will use an oil based polyurethane. Polyurethane has many advantages to polycrylic, with one major disadvantage. Polyurethane will often give a slightly yellow tinge to the surface where is it applied. If you have used white as part of your artwork, the color will be slightly yellowed.
From the Minwax Website
Minwax® Fast-Drying Polyurethane is a clear, hard finish that dries fast to protect and beautify interior wood surfaces such as furniture, cabinets, moldings, and doors. Minwax® Fast-Drying Polyurethane is among the most durable of protective coatings. Minwax® Fast-Drying Polyurethane’s long-lasting protective finish makes it ideal for use on both finished and unfinished wood.
Application Directions
- Surface must be dry and free of old finishes in poor condition, paint, wax, grease, polish, dirt or other foreign matter.
- Sand to obtain a smooth uniform surface. Remove all dust with a cloth dampened with mineral spirits.
- Stir Minwax® Fast-Drying Polyurethane before and during use to eliminate settling on the bottom of the can. Stir in such a manner as to rotate the product from the bottom to the top of the can. NEVER SHAKE.
- Apply a THIN coat of Minwax® Fast-Drying Polyurethane using a high-quality natural or foam brush.
- Let dry 4-6 hours. Then lightly sand entire surface with fine sandpaper (220 grit) to ensure an even finish and proper adhesion. Remove all dust.
- Apply second coat. If third coat is desired, repeat step 5 before application.
- After final coat, allow 24 hours before light use.
Reference
Information copied from http://www.minwax.com/products/oil_based_clear_protective_finishes/fast_drying_polyurethane.html
