Preparing the surface before mounting

Before you start

An adhesive holds only as well as the top layer of the substrate holds. Dust, old chalk whitewash, flaking paint and grease make any formulation useless: it sticks to the dirt, and the dirt does not stick to the wall. So the first step is not choosing an adhesive but inspecting the wall: run your hand over it, stick a piece of masking tape and pull it off sharply. If a layer stays on the tape, the substrate needs cleaning and priming.

Second comes moisture. The acrylic SilaFix and ALL DECOR formulations bond only a dry substrate: moisture up to 8 %, which means a wall that has stood for at least two or three weeks after plastering. The MS polymer FS-150 and FS-300 also work on damp surfaces, but that is no reason to glue onto a wet wall: water in the pores still slows down strength build-up.

Procedure

Remove everything that holds poorly: flaking paint, old wallpaper where the adhesive goes, residue of previous adhesive. Prime porous and loose surfaces — fresh plaster, gypsum, aerated concrete — and let the primer dry. Degrease smooth dense materials, glass and metal: white spirit or an alcohol cleaner will do, followed by a clean dry cloth.

Check the temperature. Acrylic formulations are applied at +15 °C and above, the decor adhesive from +12 °C, and the same conditions are needed for the next 24 hours. The MS polymer FS-150 and FS-300 work from −20 °C, rubber-based FS-200 from +15 to +30 °C. A cartridge brought in from the cold must warm up to room temperature before use.

What to watch for

An uneven wall is a separate story. A regular adhesive will not fill a gap of several millimetres under a skirting board; the part will touch at a few points and hold worse. For trim, use the ALL DECOR adhesive filler in this case, which fills the gap and sands flush; for panels, level the wall or install battens.

Hold heavy parts with supports or masking tape until fully cured, even if the adhesive grabbed at once: strength after 24 hours and strength after five minutes are two different things.