Types of primers

The primer can be the paint itself, diluted with a solvent. Nevertheless, it is not very economical to use it in this capacity, and in many cases (preparation for painting metal surfaces, fixing crumbling bases, etc.) does not make sense. Usually, special primers are used for precoating – they contain cheaper pigments and are cheaper than high-quality paints. Their external difference is in comparison with thinner paints and usually they create a matte surface, with which the subsequent coating adheres well..

Alkyd primer

It is one of the best paint primers for untreated wood (it “swells” the wood structure) – the result is an ideal surface for subsequent application of most topcoats. A highly pigmented alkyd primer is often used, which creates a semi-matt film and enhances the depth of the top color. Dries, as a rule, in 12-16 hours.

The only significant limitation is that you should not cover plaster and gypsum surfaces with such primers, since alkyd causes hairiness on them.

Acrylic (emulsion) primer

Like acrylic paints, this primer is applicable to almost all surfaces (for fresh and old plaster, cement, concrete, asbestos, wood, fiberboard and chipboard, brick). Possesses attractive consumer properties: practically does not smell, dries in 2-4 hours, diluted with water. It is not recommended to use such a primer as a protective coating for ferrous metals, since it does not protect against corrosion (over time, rust stains may appear on them).

Epoxy and polyurethane primers

As a rule, these are epoxy and polyurethane finishing paints diluted with a special solvent. In such cases, each manufacturer has its own recipe for preparing primers from them (using their own solvents).

Shellac wood primer

It is primarily intended for the isolation of knots in tree cuts, on which resin appears. Can also be used as an insulator for water-soluble stains.
The basis of such a primer is insect milky juice diluted in methyl alcohol.

Metal primers

The main purpose of these compounds is to protect metals from premature corrosion. Moreover, for different metals, appropriate primers are also used. So, for aluminum, special zinc-based primers or urethane paints are used, which protect it from pockmarking. The best anti-corrosion primer for steel and other ferrous metals is alkyd with zinc content. Moreover, there are several of its varieties: on zinc phosphate – the best anti-corrosion primer for alkyd finishing paints; on zinc chromate – used for the same purposes, but has a wider range of applications (suitable for structures that include wooden elements).

Copper, brass and bronze are usually not painted – in most cases, such materials appear on the market with already factory processing. If their protective coating suddenly began to “peel off”, then it is better to completely remove it with white spirit. Then, to maintain the natural color, polish and coat with epoxy or polyurethane varnishes.