Stelmax gap Filler and sealant for sealing and joining PVC and PVCu to itself and most porous substrates such as brickwork. Product will skin rapidly to prevent penetration of the product surface from foreign bodies and when fully cured will give a water resistant colourfast seal. Stelmax 1961 Gap Filler & Sealant is an easy to apply PVC resin, pigment and plasticiser. It will gap fill and bond readily to form strong maintenance free joints when used to bond and fill rigid and plasticised PVC. Good adhesion can also be achieved when used with many porous substrates.