Gypsum Board & Construction



Gyp accelerators are additives that shorten the setting time of gypsum plaster and setting-type joint compound by causing gypsum crystals to form at a much faster rate.​ Gyp accelerator: Standard Strength is intended to provide a slight adjustment (10 to 30 minutes) to the setting time for veneer and conventional plasters. Gyp Accelerator: Alum/Catalyst corrects plaster dry-out conditions.


  • GYP Accelerator additives are used to obtain faster setting times needed due to faster line speeds.
  • Gypsum crystals initiate the gypsum crystal growth (seeding effect)
  • Common sulphate ions will also promote the reaction:
    • Ca++ + SO-- 4 + H2O => Gypsum (CaSO4, 2 H2O)
    • Setting (= time, specific to the couple line length / speed):
      • Initial set (Knife set, stiffening time): optimum 20’’ to 40’’
      • Final set (shore A, thumb, Gilmore, thermal), hydration at the knife 55 to 75%
    • Hydration in the board core after drying must be > 95 %
    • By using this product you can reduce the soft board rejection and increase the line speed.