text: Three essential elements form the core of the bonding process, the rubber, the bonding agents and the substrate, figure 1. The selection of the polymer base and the associated compound depends mainly on the product specification. Provided that the rubber can flow into the mould without developing a significant level of cross-linking (less than 2%), a bond can be formed using any rubber compound. There are no restrictions on the use of particular compounding ingredients, although it is best to avoid substances that will bleed rapidly to the surface of the uncured stock. The rubber Compounder therefore needs to concentrate attention to matching the physical requirements of the cured rubber and the processing needs of the moulding process.