Both water-based and oil-based paints can be thinned for use in spray applicators, for ease of application, for artistic effect or for refreshing old paint. Different methods are used for different types of paint and different surfaces. For water-based paint, stirring, adding water or using paint thinner are options. Thinning oil-based paint requires solvents. You will need the chosen paint and corresponding thinner, a stir stick and a paint roller or brush. Once the supplies are gathered, thinning should take less than half an hour.
- Stir the paint
Stir the paint for at least 10 minutes to make a smoother paint that might not even require any additional thinning. Latex paints tend to separate over time, with the heavier particles sinking to the bottom.
- Choose the appropriate thinner
For water-based paint, simple tap water is usually sufficient. For oil-based paint, select a commercial thinner that is designed specifically for oil-based paint and appropriate for your intended use.
- Add the thinner in small increments
Add 1 to 2 ounces of water to a can of water-based paint and stir thoroughly. If needed, add small amounts of water until the desired consistency is achieved. For oil-based paints, follow the instructions on the manufacturer's label.
- Test the results
Apply the thinned mixture to the target surface with a paint roller or brush. Apply two coats, and evaluate the results. Check that the paint completely covers the surface, leaving no part of the surface visible. Check that the viscosity of the paint is thin enough to spread easily.