Temperature VMQ 60: -55 °C to +200 °C
Cords are extruded as open-ended billets of circular cross-section (like an O-ring). The cord achieves its sealing effect by the deformation of its cross-section once installed, on being compressed within the installation housing. Under operational conditions, the pressure exerted by the medium reinforces the sealing function.
Production of joined RSR O-rings
The normal procedure is to first cut the cords to length and then bond them using a cyano-acrylate adhesive (e.g. Loctite 406 ®). The operational temperature limit is approx. 80 °C.
With EPDM, VMQ and FKM cords, in certain circumstances the use of a special primer (e.g. Loctite 770 ®) may also be required. Ensure that the manufacturer’s product information and safety instructions are observed.
Before bonding, both ends to be joined should be roughened with a fine sandpaper and cleared of any grease using a suitable cleaning agent (e.g. Aceton ®). The two ends should not be under any pressure during the bonding process. Then check that the joint has cured completely through. The end-joined cord must not be stretched at its joint. The joint created displays a distinctly lesser degree of bending elasticity than the cord itself.
NBR Loctite 406
VMQ Loctite Primer 770 Lim 401
FPM Loctite Primer 7239 Lim 406