Use the correct type and grit sand paper
Thorough sanding is required to ensure optimum mechanical adhesion and to create a smooth finish. Bare surfaces, primers, undercoats and fillers need to be dry sanded in order to avoid the absorption of moisture.
Sanding between fresh topcoats and varnishes can best be executed with a fine grit wetordry sandpaper and water. For every surface use the correct sanding paper and grit.
Avoid mechanically sanding in combination with coarse sandpaper as this causes too rough sand marks. Also too much film thickness is being sanded down and consequently sufficient film build-up will not be achieved. After sanding remove all dust and degrease once more.
TIP: Sand bare wood along the wood grain. Always sand fresh varnish layers by hand with a fine grit wetordry sanding paper and water.
Sanding bare surfaces
Sanding bare GRP/fiberglass: P-320-360 dry
Sanding bare steel: P-60 dry
Sanding bare wood ; P180-220 dry
Sanding painted surfaces
One-component primer coats : P220-320 dry
Two-component primer coats : P180-220 dry
Fresh one-component topcoats : P400-600 wet
Fresh twocomponent PU topcoats : P320-360 wet