Special Purpose Mediums
GAC (short for Golden Artist Colors) Specialty Acrylic Polymers are based on 100% acrylic polymer emulsions. The GACs are useful as mediums or modifiers of acrylic paints. GACs can be used to extend acrylic colors, to regulate transparency, create glazes, increase gloss, reduce viscosity or improve adhesion and film integrity. GAC polymers can also be used for binding pigment solids for various effects and surfaces. Unlike the other GOLDEN Mediums and Gels, GAC Acrylic Polymers have only a minimum amount of thickeners, levelers, defoamers and surfactants to ensure good film formation.
The consistency of the GAC polymers is more fluid and thin than other GOLDEN Mediums, so they will reduce the thickness of most GOLDEN Acrylic Paints. GOLDEN Fluid Acrylics are slightly thicker than the GACs, but will exhibit less change in viscosity with the addition of a GAC polymer.
Each GAC is a unique polymer with unique benefits and applications. Refer to the product descriptions below to find the proper medium for a particular applications.
For health and safety information, download the Safety Data Sheet [PDF].
GAC 100 Multi-Purpose Acrylic Polymer is a sealer that helps prevent Support Induced Discoloration (SID) caused by impurities that are drawn up through a substrate as the acrylic paint dries. GAC 100 is also useful for diluting and extending colors, increasing flexibility and film integrity, sizing for fabric and sealing for wood. GAC 100 will wet out solids, including pigments, more readily than other polymers and is useful for artists formulating their own paints. (Item# 3910)
GAC 200 Promotes Adhesion / Film Hardness and is the hardest and least flexible polymer offered. It is Ideal for mixing with acrylic colors to increase film hardness, reduce dry film tack and to increase adhesion to many non-porous surfaces. Dries to a clear, high gloss, finish. GAC 200 is not recommended for flexible supports. (Item# 3920)
GAC 400 Stiffens Textiles / Fibers and is useful for stiffening unprimed canvas or sculpting and shaping fabric. Fibers saturated with GAC 400 will dry to a hard, stiff film. (Item# 3940)
GAC 500 Extends Fluid Acrylics for a unique balance of film hardness and flexibility offering increased leveling, increased mar resistance and decreased dry film tack. GAC 500 is particularly useful for extending Fluid Acrylic Colors with minimal property change. It can be mixed with Airbrush Transparent Extender for a fast-drying, sprayable isolation coat. (Item# 3950)
GAC 700 Clear Sealing Polymer increases film clarity and transparency, while minimizing shrinkage. GAC 700 is useful for sealing porous materials. (Item# 3970)
GAC 800 Reduces Crazing in puddles, pours, and other thin, pourable paint applications. "Crazing" is the formation crevices in surfaces that develop as acrylic paints and mediums dry. The addition of GAC 800 promotes drying with a smooth, even film, good gloss and flexibility, but with moderate clarity. GAC 800 is also useful for adhesion to chalky surfaces. (Item# 3980)
GAC 900 Fabric Painting Medium, when heat-set properly, offers a very soft hand and laundering stability. Mix with High Flow Acrylics to produce "tie-dye" effects, or blend with GOLDEN Heavy Body, Matte or Fluid Acrylics for brush or screen application. For more information on fabric painting see our Application Information Sheet. (Item# 3990)