Home » Reducer Reducer Written by Bryan Joslin on November 1, 2023 A solvent used to thin automotive paint for proper application viscosity. Related Articles: What is Urethane Primer Good For?Eastwood DIY Auto Painting FAQ’sHow to Paint Your Car With Single Stage PaintTips and Tricks For Applying Eastwood Chassis Black PaintWill Thinning Paint Make it Last Longer?