Coating Excellence Guide

Lifting/Frying/Pickling

Swelling or lifting of previous layer(s) can occur during spraying, caused by partly dissolving previous layers.

Cause 

• Incompatibility: the paint applied is unsuitable for the substrate. 
• Degreaser too aggressive for substrate (primer, filler and/or topcoat). 
• Possibly poor adhesion of the previous painted layer. 
• Substrate not hardened thoroughly/not completely dry. 
• Application of the paint system too heavy. 
• Extraordinarily long flash-off time between coats. First coat with extra-long flash-off time is dissolved by next coat.

Prevention 

• Always do a solvent test on/around the area to be repaired. 
• Select suitable products for each substrate. 
• Mix the products according to Technical Data Sheets and use correct spraying technique; do not overload. 
• Use the correct drying times/temperatures. 
• Apply the next coats directly after recommended flash-off time.

Remedy 

• In case of minor lifting, sand down to a sound layer after drying. After sanding, apply the refinish system carefully again. 
• Always spray sensitive substrates carefully: 
− In thin coats and with sufficient flash-off time between each coat. 
• In event of severe lifting, remove the layers completely before applying the new paint system.

Orange peel

Freshly applied paint shows poor flow and looks like a skin of an orange (peel).

Cause 

• Paint is too thick, spraying viscosity too high. 
• Incorrect hardener, too fast. 
• Incorrect thinner, too fast. 
• Spraying pressure too high/too low. 
• Spray gun set-up: nozzle size too big. 
• Extremely high temperatures. 
• Paint materials too cold.

Prevention 

• Use the correct mixing ratio (use measuring stick or mix over scale). 
• Check viscosity. 
• Use recommended hardener and thinner for job size, temperature, and air flow. 
• Apply products according to the TDS. 
• Use correct spray gun set-up for products. 
• Ideal spraying temperature is approximately 20°C/68°F. 
• Avoid spraying at extremely high temperatures. 
• Ideal storage temperature is approximately 20°C/68°F.

Remedy 

• Polishing will rectify minor orange peel effect. 
• In case of severe orange peel effect, sand and re-spray the object.

Sanding marks

Fine/coarse scratches in different patterns, circular or random, can appear in the topcoat system, either immediately or after a while.

Cause 

• Wrong sanding grade used, too coarse for the products applied subsequently. 
• Insufficient drying/curing of the primer/surface/fillers. 
• Contamination on the object causing scratches: coarse dirt particles, etc.. 
• Wrong sandpaper/sandpaper grit used for manual sanding.

Prevention

• Check TDS for correct sandpaper. 
• Make sure primer/surfacer or filler is thoroughly cured/hardened through before sanding. 
• Keep object to be painted clean, also during sanding. 
• Use appropriate hand-sanding paper for manual sanding.

Remedy

• Thoroughly dry the paint system first. 
• Sand substrate with correct sandpaper and sandpaper grit. 
• If necessary, completely remove scratches from previous layer by sanding with the appropriate sanding grit and steps. 
• If necessary, apply primer/surfacer/filler. 
• Apply the top coat system .