Transtar Hydroflex Super Hi-Build Waterborne Primer, 1G. Hydroflex Super Hi Build is a ready to spray Waterborne Acrylic Urethane primer surfacer designed for professional refinishing of both thermoset and thermoplastic substrates.  This product has superior fill and build properties and provides outstanding adhesion and topcoat holdout.  Specifically designed for use by the Bumper Recycler Industry, this low odor, easy-to-apply formula can be topcoated with most basecoat/clearcoat products (water and solvent) and Single Stage (enamels, urethane and polyurethane).  Follow paint company topcoat recommendations when using this product.  Hydroflex Super High Build covers in 1 - 3 coats, sands easily wet or dry in 1 - 2 hours without feather-edge tearing. 1221