Environment

Dust contamination

Particles of dust or other contaminants that have settled on the wet paint and become trapped in it during drying. Visible as small raised specks on the surface of the coating — each particle forms a characteristic bump with a shadow around it.

Cause

Vehicle preparation

Vehicle not cleaned thoroughly before painting — dust and dirt from hard-to-reach areas
Sanding residue left on the substrate
Fibres from the edges of masking paper or masking tape
Failure to use a tack cloth immediately before application

Booth and equipment

Contaminated base coat
Blocked ceiling or extraction filters in the spray booth
Booth pressure too low — dust is stirred up instead of being extracted
Unsuitable ceiling filters or old, deteriorating air lines
Contaminated booth floor, air lines and walls
Inadequate maintenance of the compressed air system

During application

Work clothing made of fibres that fray — releases dust while working
Excessive movement around the vehicle during painting — disturbs the airflow and stirs up dust
Electrostatic charges attracting dust — particularly on aluminium and plastics
Unnecessary sudden movements in the spray booth

Prevention

Preparation

Wash the vehicle before starting the repair process
Thoroughly clean the area around the repair — apertures, wheel arches, hard-to-reach areas
When dry sanding, always use dust extraction and clean thoroughly after sanding
When wet sanding, do not allow the slurry to dry — clean it off immediately
Use good-quality masking paper and tape with the smooth side facing out

Application

Use an anti-static tack cloth to remove dust immediately before application
Use paint strainers to filter the paint before pouring it into the spray gun
Work clothing should be clean and lint-free — preferably nylon or anti-static
Avoid unnecessary movement and walking around in the booth during painting
Use an anti-static cleaner and earthing to remove electrostatic charges
Keep the air hose to the spray gun off the floor at all times during painting
After painting, hang the hose back up — do not drop it on the floor

Booth maintenance

Check and replace the spray booth filters systematically
Clean the booth regularly — floor, walls, air ducts
Check the compressed air system systematically
Maintain the correct pressure in the booth
Use the correct filters: ceiling and extraction

Repair

Fresh paint — small dust particles can be removed with a needle or a small pin while the paint is still wet
Dried paint with minor contamination — sand with fine abrasive paper and polish
Large particles or deeply embedded contamination — sand back the substrate and repaint from the top coat