What is the recommended pretreatment of an aluminum substrate?
The aluminum substrate can be pretreated by:
1) manual cleaning with nitro thinner, and then wiping with an abrasive fleece;
2) manual cleaning with a cold preparation, then rinsing with hot water and wiping with an abrasive fleece;
3) manual cleaning with special preparations containing phosphoric acid (non-cleanable components with joints and joints, as the residues remaining in them may damage the coating), then chafing, abrasive fleece;
4) cleaning with a jet of steam or hot water under high pressure.
Whenever, the appropriate pre-treatment should be selected depending on the nature of the object. The lyes are aggressive towards aluminum and therefore should not be used.

Which coating materials are suitable for the aluminum substrate?
Alkyd varnishes are recommended for aluminum substrates (usually on a special primer to improve adhesion), polymer, e.g. made of acrylic resin, PVC, made of epoxy resins, polyurethane and 2-k-acrylic.
Of course, the appropriate material for the coating is each time selected depending on the anticipated chemical load.