The substrate must be sound, clean, dry and free of all contaminants such as dirt, oil, grease, cement laitance, old sealants and poorly bonded coatings which could affect adhesion of the primer and sealant. The substrate should be of sufficient strength to withstand with the stress induced by the sealant during movement. Use techniques such as wire brushing, grinding, grit blasting or other suitable mechanical methods to remove all weak substrate material. Repair all damaged joint edges with suitable Sika® repair products. Remove all dust, loose and friable material from all surfaces before application activators, primers or sealant.
Where joints in the substrate are saw cut, after saw cutting, all slurry material must be flushed away and joint surfaces allowed to dry.
For optimum adhesion and joint durability of critical, high performance applications such as joints on multi-storey buildings, highly stressed joints and extreme weather exposure the following priming and/or pre-treatment procedures must be followed:
NON-POROUS SUBSTRATES
Aluminium, anodised aluminium, stainless steel, galvanised steel or glazed tiles
- Lightly roughen the surface with a fine abrasive pad.
- Clean the surface.
- Pretreat the surface using Sika® Aktivator-205 applied with a clean cloth.
Other metals, such as brass, bronze, copper and titanium-zinc
- Lightly roughen the surface with a fine abrasive pad.
- Clean the surface.
- Pretreat the surface using Sika® Aktivator-205 with a clean cloth.
- Allow a waiting time.
- Apply Sika® Primer-3 N by brush.
Powder-coated metals
- Perform preliminary trials to verify adhesion. For more information contact Sika® Technical Services.
PVC
- Clean and prime the surface using Sika® Primer-215 applied with a brush.
POROUS SUBSTRATES
Concrete, aerated concrete and cement based renders, mortars and bricks.
IMPORTANT: Avoid excessive application of primer causing puddles.
- Prime surface using Sika® Primer-3 N applied by brush.
ASPHALT (ACC. TO EN 13108-1 AND EN 13108-6)
Fresh cut or existing cut asphalt must have a clean bonding surface with a minimum of 50% exposed aggregate.
IMPORTANT: Avoid excessive application of primer causing puddles.
- Prime the surface using Sika® Primer-3 N applied by brush.
Note: Primers are adhesion promoters and mprove the long term adhesion performance, not an alternative to improve poor preparation and cleaning of the joint surface.