You can use alcohols for thinning epoxy. But this can cause them to become brittle after they cure. Try using a little isopropanol (not 70% like rubbing alcohol, but the anhydrous from Tamaya paint thinner). You might want to experiment around with how much to use and how thin the Epoxy gets and how brittle it cures when diluted. You could always reduce the amount of hardener to get a less brittle product when cured.