Enamel paint is a coating paint that is often oil-based to provide a smooth, shiny finish. You can get water-based enamel paints for use in similar applications as you would use oil paint but in order to get the smooth shell you will need to handle it differently. By thinning out the enamel paint you can achieve the same clean application that oil-based paint would provide. Luckily you can easily thin your enamel paint yourself.
Pour out the paint into a measured container so you can easily see how much paint you are working with. Use big container so there will be space for adding the water.
Calculate the amount of water to start off the thinning. Allow 1/4 cup of water for every 1 pint of paint. So for 4 pints of paint you would use an entire cup of water.
Pour the calculated amount of water into the container of paint. Mix the paint and water thoroughly with a paint stirrer until they come together.
Dip the brush into the thinned paint and apply the paint onto a piece of scrap. Check the consistency to see if the paint goes on smoothly.
Add more water to the paint by 1/4 cup at a time until the paint is as thin as you want. Stir the paint thoroughly, and test it after each addition to avoid over-thinning.