How to Make Wipe-On Polyurethane

Gather the proper materials. Most polyurethanes have a mineral spirit base, and this is the solvent used to thin them down in preparation for wiping. Some newer finishes, however, are water based and can be diluted using simple tap water. Your product's label will contain the information necessary to make the proper determination on which thinner to use.

Pour the thinner into the polyurethane and mix thoroughly. For smaller projects such as a piece of furniture, a mixing stick will be sufficient. For larger jobs like a bar-top, you might need a drill equipped with a paddle mixer due to the large amount of polyurethane you'll need to prepare. Test the consistency with a clean rag, adding solvent as needed until the finish easily transfers from the rag to the surface being coated.

Continue mixing and adding solvent during use. The solvent evaporates during the coating process, and the polyurethane will start to thicken. Add more thinner as necessary to maintain the proper consistency for wiping. Keep stirring the mixture to prevent cloudiness in the finished product.