Adhesives

Failure of a product to adhere can lead to major expense and inconvenience.
Virtual Decorator
Project guide service
Paint calculator
Wallpaper calculator
Related Projects
Related Tips
Page 1/1
A clean surface
Contaminants
Cleaning the surface
A dry surface
Bare surfaces
Unpainted surfaces
Bare wood
Compatibility of materials with adhesive
Examples of materials requiring special attention

A clean surface

Adhesives must remain firmly bonded to a surface despite any movement of the materials and possible pressures on the materials they are holding in place. It's improtant that the bonding surfaces must be clean.

If the surfaces are not clean, the product may lose its adhesiveness sooner or later by pulling away the contaminant. For example, applying adhesive over dust will lift the adhesive by pulling away the dust as soon as there is movement of the materials.

Contaminants

Some materials prevent good adhesion of products, including grease, oil, fats, silicone, creosote, tar, wax and soot. They must be removed.

For the same reason, the surface must be free of all loose or foreign matter such as efflorescent salts and any other substance not firmly attached to the surface.

In the case of solvent-based products, the surface must be free of all substances like asphalt that are soluble.

Cleaning the surface

Various cleaners may be used, depending on the surface and its condition, as indicated below.

It is important to carefully read the instructions when using these cleaners to learn the required dilution, method for application and safety precautions to take.
After cleaning, a thorough rinsing and drying of the surfaces is usually required.
The cleaners
CleanerTypical Use
Soapy waterDust and other normal dirt
Phosphoric acid solutionRust
Rust-Oleum 33599Asphalt
AcetoneOil or grease on metal
BleachMould
Trisodium phosphate solutionOil stains or grease spots
Muriatic acid solutionEfflorescence
StripperOld paint or finish

A dry surface

Surfaces should be dry, although some adhesives can be applied on damp surfaces (check the product data sheet).

If the surface is not dry, the moisture it contains may prevent or reduce proper adhesion. Even if a product can be applied on a damp surface, too much moisture (humidity over 20%) may cause pressure on the product and cause it to lift.

Bare surfaces

An adhesive should always be applied on a bare, unsealed surface. To perform properly, the adhesive must bond firmly to the surface. If the surface is not bare, but covered with paint or another surface coating, the adhesive will bond to it, and the adhesion of the surface product may not be enough to keep the materials together. Applying an adhesive on a coated surface is the same as applying it on the coating itself. The coating must be well bonded to the material and the adhesive must be compatible with the coating.

Unpainted surfaces

The labels and data sheets that come with adhesives often say "The surface must be free of paint." The reason is simple: these products must ensure an extremely strong bond between the surface and the material. In many cases, the adhesion strength required exceeds that of a coat of paint on the surface. Adhesives may also affect the paint film and reduce its strength. Moreover, paint prevents surface absorption of part of the water or solvent in the adhesive and significantly slows its drying time. For all these reasons, it is generally recommended that painted surfaces be sanded down.

Bare wood

With wood, it is even more important that the surface be bare because adhesives dry faster on bare wood than sealed wood. Bare wood can absorb some of the water or solvents in the adhesive.

Compatibility of materials with adhesive

The lack of adhesion on some surfaces may be due to an incompatibility of the adhesive with certain surfaces. Always read the product data sheet to make sure the product is compatible with the material that will receive the adhesive and the material you want to bond it to. For example, several construction adhesives cannot be used with plastics because they attack and deform them.

Examples of materials requiring special attention

The adhesion of metals calls for an adhesive with specific adhesion and drying characteristics.

Floor coverings require specific viscosity characteristics.

Some materials, like rigid polystyrene insulation (Styrofoam®) or plastics, are extremely sensitive to solvents and may break down if not glued with a specially designed adhesive.

Parquet flooring demands very specific precautions and requires a specialized adhesive.
Page 1/1