A fixing device is disclosed for use on hard surfaces such as exterior walls, wood, glass or metal for supporting elements, particularly elongate elements, against such surfaces. The fixing device comprises in combination a holding member, for example a plastics plant tie cable grip or pipe clasp, and a portion of an adhesive composition of putty consistency. The holding member has a cup portion which defines a socket. The composition is a filled hardenable adhesive composition including an adhesive component such as epoxide resin and a hardener component such as a mercaptan/amine-accelerated polyamide hardener which are separately present in the composition in pre-determined proportions such that the composition is workable by hand to mix the components and activate a hardening reaction. In use, a portion of the composition may be separated from a ribbon and mixed between the fingers to form a pellet which is pressed into the socket of the holding member to fill the socket, the device then being pressed onto
