When it comes to spraying paint there are two types of paints. Oil based paints and latex based paints. Oil based paints can be cut using paint thinner and the dry time can be extended, helping the paint flow easier. To extend the dry time of oil based paints I typically use Penetrol. When using latex based paints the paint can be thinner using water as it’s cutting agent. And for extending the dry time of latex I typically use Floetrol. When thinning latex based paints you should start out using 1/2 cup of water for every gallon. If the 1/2 cup has been added and you still think it needs to be thinned more you can add 1/8 of a cup until you reach your desired viscosity. When thinning oil based paints you should use 1 part paint thinner for every 3 parts paint. Keep in mind thinning paint can slightly change the final color it can also decrease the coverage. So make sure not to thin the paint too much and keep in mind it may need more than 2 coats to cover properly.