| Few surfaces are ideal for bonding.
Priming the surface is a means of transforming the
substrate, either chemically, physically or both,
into an ideal condition for successful bonding,
thus supplying long-term performance. The simplest
form of priming is wiping the prepared surface with
a conditioner (such as Sika Aktivator®) which
reacts with the surface providing improved "wetting"
characteristics and more reactive sites. |
Porous and rough surfaces require
a primer with "film-forming" properties
to re-profile the surface, producing a denser, more
even bond line. In some cases, the film-forming
primers also prevent plasticisers or resins present
in the wet adhesive from being absorbed into the
substrate which can cause discoloration or bond
line starvation. Primers must always be allowed
to dry thoroughly before application of the Sikaflex®
adhesive. |
If left too long, primed areas must
be reapplied or reactivated. Minimum and maximum
drying times are given in the surface preparation
table in this guide. Primed surfaces should be protected
from contamination by dust, dirt, grease, vapours,
moisture, etc., until the bond is formed. Please
note that primer bottles should be shaken prior
to use where-ever necessary. Ensure that primer
bottles are resealed after use. |
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