Bleed Through

 

Discoloration of the topcoat (occurs most commonly on red or yellow stains) when painting over an existing finish

The solvent in the fresh topcoat has redissolved the soluble pigments in the old finish, allowing it to seep upward into the fresh paint, thus discoloring the top coat

For minor defects :

 

Allow the the stained topcoat to fully cure; then spray a suitable sealer over, it followed by a fresh coat of color. Refer to the product’s specification sheet for details
For major defects :

 

Sand to bare wood and recoat

Conduct a solvent test on a small area to verify the possible presence of soluble dyestuffs in the existing coated surface

Blistering

 

Blistering, sometimes called pimples, are bubbles or swelled areas that show up in the paint surface weeks or months after a paint job

Moisture related causess :

 

  • Moisture absorption from the substrate (especially from putties and fillers) before painting
  • Moisture condensation on the substrate created by a sudden change in temperature (e.g. the hot piece straight out of the oven into a cooler room)

 

Contamination related causes :

 

  • Contamination of the substrate by water, grease, oils, etc.
  • Use of incompatible products or unsuitable thinners
  • Exposure of the painted surface to a high level of moisture or rain before complete through drying
  • Thinning of water-borne products with tap water (containing mineral salts)
  • Presence of water in the compressed-air line

After through drying :

 

  • If the blisters formed between the final coat and the undercoat, sand until you reach a completely smooth surface, then re-coat
  • If the blisters formed between the substrate and the undercoat, sand thoroughly, clean accurately, and repeat the complete paint system
  • Ensure that the surface is thoroughly cleaned before any operation (use compressed air and silicone remover/ degreaser)
  • Protect the surface before the paint application, and immediately after, to avoid moisture condensation
  • Refer to the product’s specifications to avoid any incompatibility
  • Check the compressed air supply periodically
  • Allow water to evaporate fully after wet sanding
  • Only dry sand polyester putties

Cratering / Fish Eyes

 

Small, circular, crater-like openings that appear either during or shortly after laying down a coat of paint or primer

  • Incorrect use of antistatic cleaning cloths that can contaminate the substrate
  • Presence of grease, oil, silicon, or wax on the substrate
  • Presence of grease, oil, silicon, water, or wax on the substrate in the compressed air
  • Solvent contaminated spray gun when using water-borne products

After through drying :

 

  • Remove by sanding the affected paint, clean thoroughly, and re-spray
  • If the paint still forms craters, anti-silicones may be required in the mixture. Contact your local Asia Paint representative
  • Clean and degrease the substrate thoroughly before spraying, using specific silicone removers. Remove the solvent with a clean cloth before it dries off
  • Check the spray booth filters and the oil/water separator and drain if necessary
  • Always check the surface before spraying the next coat; if necessary, repeat as indicated above
  • Use clean spray equipment
  • Do not use products containing silicone in the spray booth
  • Clean with suitable solvents and allow the spray guns to dry after using water-borne products

Gloss Difference / Hazing 

 

Dulling of certain portions of a finish’s gloss or shine as it dries or ages

  • Insufficient drying time of the undercoats
  • Use of thinners that are too aggressive
  • Use of inappropriate hardeners
  • The coatings dry too slowly in an environment with excessive humidity
  • Low baking with insufficient air circulation
  • Exposure of the painted substrate to weathering and/or aggressive chemical agents when it is not yet through-dried

After through drying :

 

  • Polish using an abrasive compound according to the degree of gloss
  • If polishing does not restore the gloss, flat with abrasive paper, then re-spray
  • Always follow the technical data sheet instructions, apply the undercoats according to the suggested film thickness, allowing adequate drying time between all coats
  • Follow the baking temperatures for undercoats and finishing coats in well aerated spray booths, especially in case of low room temperature and high humidity
  • Avoid exposure of the painted surface to any aggressive conditions in the first days after painting

Haloes

 

The finish displays different color shades, especially near the edges

– Poor hiding power

  • Unsuitable application techniques, especially in the least accessible zones
  • Too few coats applied
  • Insufficient or non uniform coats
  • Low covering color requiring a specific colored undercoat
  • Incorrect mixing ratio and/or low viscosity of the paint

– The flash-off between coats or before the clear coat application was too short

– Application of the basecoat was too thick / thin

  • Sand slightly and recoat
  • If some haloes appear when spraying, spray in a uniform method
  • Use appropriate application techniques to reach a correct film thickness on the whole surface
  • Apply a recommended number of coats as indicated on the product specification
  • Always check if the finishing coat needs a coloured undercoat: if this is the case always apply the specific coloured undercoat
  • Always stir paint thoroughly and filter it before application

Metallic Clouding

 

The fresh coat of metallic paint shows colour differences: after spraying, light and darker spots (clouds) appear

Improper application technique, i.e.

 

  • First coat is too wet with a dry grip coat on the top
  • Incorrect adjustment of the spray gun (air cap, air pressure)
  • Incorrect spray viscosity
  • Insufficient stirring of the paint
  • Before applying the clear coat, apply a new uniform light/grip coat of the matt base, reduced with the specific thinner as indicated on the relevant product specification sheet
  • If the clouds appear after the clear coat application, sand the surface and re-spray the base coat and clear coat

Follow accurately the instructions on the technical data sheet :

 

  • Check the adjustment of the spray gun
  • Stir the thinned base color properly and filter before spraying
  • Use recommended thinners as indicated on the product specification sheet

Orange Peel

 

Uneven paint film that has a texture that looks like an orange peel

Usually caused by poor paint flow, contributed by :

 

  • Poor spray gun technique (gun held too far from the surface, causing the paint to dry before it reaches the surface)
  • Unsuitable spray gun adjustment (air cap, air pressure, etc)
  • Viscosity of the paint is too high for spraying
  • Use of too fast or unsuitable thinners
  • The flash off between coats are too short
  • The substrate’s surface temperature is too high / the temperature in the spray booth is too high
  • The paint is applied too thick / thin

After through drying :

 

  • Rub out affected areas with very fine abrasive paper and polish
  • In severe cases, resand and re-spray
  • Use proper spraying techniques
  • Use the suggested thinners as per the product’s specification sheet
  • Check the viscosity of the paint and the air pressure settings before spraying
  • Check room temperature and ventilation before spraying
  • Apply uniform coats and adhere to the recommended flash off times between coats

Peeling

 

Loss of adhesion between a paint film and the substrate, causing sections of paint to separate from the surface

  • Presence of wax, fat, silicone, oil, or other contaminants
  • Inadequate surface preparation
  • Inadequate product used
  • Unsuitable temperature during application
  • Incorrect film thickness
  • Remove loose paint film
  • Conduct proper surface preparation
  • Adhere carefully to the product’s recommended coating system and procedure, and re-apply the coating
  • Check the substrate and choose a suitable paint system
  • Conduct proper surface preparation
  • Remove any contamination that can adversely affect the coating’s adhesion
  • Check the spray viscosity: lower viscosity increases the substrate wetting and improves the adhesion
  • Observe the flash-off time between coats indicated on the product specification sheet
  • Avoid using products from different paint manufacturers in the paint system

Pin Holes

 

Deep holes in the paint surface

  • Incorrect application of the filler (sanding, sealing, etc.)
  • Too fast drying (oven or IR lamps) of the filler applied in too thick layers
  • Inefficient filling technique and putty sanding (leaving hollows)

After through-drying :

 

  • Sand the paint or filler to completely remove the pinholes, apply a suitable sealer filler, sand accurately, and reapply the final coat
  • Follow the instructions of the product specification sheet on the correct application methods, flash-off and drying times
  • Build up the putty in thin layers in order to avoid trapping air in the mass

Sanding Marks

 

Patchy finish, with fine round scratches on the finishing coat

  • Unsuitable polishing techniques (speed, pressure) or unsuitable materials (rubbing compound, etc)
  • The film has not dried through yet

After through-drying :

 

  • Repeat the polishing operation
  • If necessary, sand slightly and re-paint

 

  • Use specific polishing techniques and materials dependent on the finishing coat
  • Allow the film to through dry before polishing it

Sagging

 

Paint runs on vertical surfaces

  • Use of unsuitable hardeners/thinners
  • Incorrect viscosity
  • Heavy application of product
  • Incorrect flash-off between coats
  • Incorrect air gap
  • Incorrect spray fan

After through drying :

 

  • Polishing to remove the sags
  • Sand and repaint if necessary
  • Consult the product specification sheet carefully and use correct hardeners/thinners in relation to the temperature and the relative humidity
  • Ensure that the spray equipment is perfectly clean and in good working order

Spray Dust

 

Impurities settled on the surface before the paint is fully dry

  • Inadequate masking of the substrate
  • Insufficient ventilation in the spray booth
  • Poor spray gun techniques (e.g. spray pressure too high)

Polish the coated surface, otherwise sand and remove the defect

  • Ensure that the spray environment is as clean as possible
  • Adhere to the application techniques as indicated in product specification sheet
  • Check the airflow in the spray booth

Water Marks

 

The edge of evaporated water droplets can be seen on the paint surface

When water drops on the paint surface and evaporates (especially on horizontal surfaces) the outline of the drops may still be seen. Usually occurs when the painted surface has been exposed to rain or water drops just after painting

After through drying :

 

  • Sand and polish
  • If repeated polishing is not effective, sand the affected area and re-spray
  • Protect the painted surface as soon as possible and avoid contact with water
  • Ensure that the painted surface is sufficiently dry to avoid the covers from sticking onto the painted surface

Wrinkling

 

The paint surface acquires a finely wrinkled appearance

  • Paint applied to a solvent sensitive and/or only partially dry substrate, without previous application of a suitable sealer
  • Use of too aggressive or inappropriate thinner
  • Use of unsuitable sealers for the substrate – In case of two-coat finishes, partial removal of the sealer by sanding, without correct sealing
  • Too high film thickness

After through drying :

 

  • In case of a slightly wrinkled surface sand with fine sand paper and re-spray
  • If the surface shows serious signs of wrinkling, thoroughly remove the paint and reapply
  • Ensure that the substrate is not solvent-sensitive and has dried through. If it is the case, seal completely with a suitable sealer (e.g. a water thinnable sealer)
  • It is possible to apply a two-pack sealer in very thin coats to sensitive substrates, allowing long flash-off times between coats
  • Use only recommended hardeners and thinners