Well, oil-based paints are thick and can be hard to spread at times. In order to get the best paint job on a particular project, you need to know how to thin oil-based paints out so they can be easily spreadable. If you add too much thinner to the paint, it can make it too runny and end up ruining the paint job. So it is important to use the right amount of thinner. If you dilute the paint by one-third, you should be able to get the paint to the right consistency to use. It is best to read the instructions on the paint can before you do this to be sure. If you don't, you could end up messing up your paint job!