Polyurethane is a versatile polymer that can be rigid, flexible, adhesive or liquid, depending on the application. The form most often used by painters and crafters is liquid varnish. When sprayed or painted onto a solid surface, polyurethane creates a clear protective top coat that seals against moisture. Though it's a highly useful product, many painters dislike the fact that polyurethane takes considerable time to dry. There are, however, several easy ways to dry it faster.
Things You'll Need
- Mineral spirits
- Quick-dry sealer
- Liquid siccative
Spray a thin coat of spray polyurethane onto the desired surface. Spray polyurethane, as opposed to brush-on varieties, is easily applied in a thin layer over a broad surface. By applying multiple thin coats rather than a single thick coat, drying time is greatly reduced.
Thin the polyurethane with mineral spirits. Mix one part mineral spirits with one part polyurethane and brush it onto the desired surface. Polyurethane dries in two parts, the first of which is the evaporation of the thinner. By thinning out the polyurethane, this first step in the drying process will pass more quickly and the curing process will not be affected.
Set the varnished item in a warm, dry place with plenty of airflow. Position a fan near the nearby to assist in the evaporation process and keep the room warm. Do not, however, use an electric heater or gas stove to warm the room because dangerous reactions could occur with chemical fumes.
Apply a coat of quick-dry sealer to the surface and allow it to dry. Apply a second coat if desired, and allow it to dry before adding a layer of polyurethane. Rather than applying several coats of polyurethane and allowing each coat to dry for a full day, you can greatly reducing drying time by using quick-dry sealer for the first two coats and finishing with polyurethane.
Mix a small amount of liquid siccative, such as Japan Drier, with your polyurethane before applying it. This substance is often used by sign painters and craftsmen to decrease the drying time of paints and varnishes.
Switch to a water-based polyurethane instead of an oil-based varnish. Water-based polyurethanes dry much faster, while increasing room temperature and airflow further reduces drying time.
- Photo Credit John Howard/Lifesize/Getty Images