Whats the best thing to thin out acrylic paint?

Want to do a piece with paint flowing from a small hole in a cup that spins but i need to thin the paint so its runny but not to runny. any sugestionsWhats the best thing to thin out acrylic paint?
Yes, water is the natural choice for acrylics because of their water solubility, however for your purposes, you might want to use an airbrush medium that will give you the advantage of a more even color. If using too much water, you will end up with a water colour effect that probably won't suit your purpose.Whats the best thing to thin out acrylic paint?
Use water, but don't use more than about 1/3 water or the paint will have poor binding abilities. Acrylic medium mixed with water and paint would improve the binding qualities. if you're not concerned with it lasting for 100 years, just use water.
Acrylics are water soluble, so they can and should be thinned with water. You do have to mix the water in quite well, or the paint will separate. If you mix in too much water, just add more paint. Good luck.
Acrylics are water-based paints. Therefore you can use just plain water to thin them out.
Have your tried using acrylic medium? you'd probably get a runnier effect with that since it's thicker than water.
Water works fine. It thins it's opacity though, so you might want to do 2 or more coats of watered down acrylic.
Water
Water is best.