 How can I thin out the art resin mixture? The best way to thin out the art resin mixture is by heating it up in a warm water bath. This will alter the viscosity, making it more runny, which some people think makes it easier to work with, but it will also decrease the pot life and the cure time. Do not attempt to add in any solvents as that will compromise the non-toxicity of the product and also its delicate nature.