When building tools or parts that require several pours or layers it is important to ensure the layers bond together well.

The second and subsequent layers should be made when the previous layer is only slightly warm to the touch and tack-free.

Do not allow any moisture, for example damp air, to come into contact with the resin as it cures; this can cause it to ‘blush‘ or look cloudy and inhibits adhesion of subsequent layers.

A thin dusting of the surface with dry silica sand will also improve adhesion.

When casting resins, joints between tool sections should be ground and chemically etched to ensure a good bond.