The original bonding aid

For years, the DIY and hardware market has used A.Shak’s PlasterKey as in industry benchmark for bonding plaster. 

PlasterKey is a universal, water based bonding aid ideal for keying smooth surfaces without the need for chipping, saving time and mess. It is specifically designed for use in the building industry to bond sand and cement plaster to smooth surfaces by creating a non-structural bond for cement and gypsum-based plasters. 


When plastering with a sand/cement plaster a scratch coat needs to be applied to the surface first. The scratch coat consists of two parts river sand, one part cement with PlasterKey added to create a loose mix. With either a block brush, trowel or tyrolean machine, cover the surface to be plastered. The rougher the surface the better. Allow the scratch coat to dry, preferably overnight, and then plaster as usual. 


PlasterKey can be added to your plaster mix at a rate of one litre to 10 litres of water. This will create a less porous plaster. When plastering with gypsum-based plasters, apply PlasterKey directly on to the surface with a brush or roller. Plaster the gypsum-based plaster straight onto wet PlasterKey. It is best to do the application in small stages to let the PlasterKey dry before applying the gypsum plaster. 

Do not add PlasterKey to a gypsum-based plaster mix.

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