Application
Mark the area where the adhesive has to be applied for correct alignment. Apply plenty of the SikaFast®-1640 Activator with the brush which is part of the closure of the bottle to one of the bonding surfaces. On glass to metal applications, the SikaFast®-1640 Activator is applied on the glass side.
The SikaFast®-1640 Activator is free of solvents and must be liquid when joining the two parts. It therefore must not dry off.
Apply a thin layer of the SikaFast®-1640 Gel onto the other substrate.
Join the part with the activated glass surface and hold with light pressure for about 20 seconds. Excess adhesive must be removed immediately (latest within 40 seconds from joining) with a clean cloth.
The adhesive reaches about 50 % of the final strength after 15 to 20 minutes.
Optimum temperature for the bonding process is between 15 °C and 25 °C. The influence of the reactivity by temperature changes has to be respected.
Avoid bonding on glass surfaces that were exposed to direct sun light (hot surface). Due to the limited gap filling capability of SikaFast®-1640 the bond faces must have compatible contours. The bonded area must not exceed 10 cm², due to higher risk of stress-cracking.