KAROCLE

Wrinkling

Rippled paintwork surface with uneven grooves. The upper coat dries faster than the coat under it. Occurs only with synthetic resin paints.

Causes

1. Synthetic resin applied too thick
2. Insufficient addition or no addition of drier
3. Unfavorable drying conditions (e.g., very high ambient temperature)

How to avoid

1. Keep to recommended film builds.
2. Add amount of drier specified in the mixing formula.
3. Ensure that drying conditions are favorable.

Repair

For minor wrinkling, allow the affected surface to dry completely and then sand it off to a well-cured coat and apply a new finish. For severe wrinkling, strip the paint layer completely and repaint.

Dust contamination

Usually small, irregular lifting of the paint film caused by foreign matter (e.g., dust/dirt) which can occur in different sizes, shapes, types and patterns.

Causes

1. Poor cleaning of substrate prior to painting
2. Lint containing overalls or clothes
3. Spray booth dust problem due to dirty and clogged filters causing incorrect air supply and incorrect overpressure
4. Intake of contaminated air (polishes, fine dust etc.) from other parts of the workshop

How to avoid

1. Clean thoroughly before applying the paint.
2. Use lint-free overalls and cloths.
3. Have air flow settings set by the booth manufacturer.
4. Ensure regular cleaning and maintenance of the spray booth and filters.
5. Ensure that polishing/finishing areas are away from the paintshop and are separated by a filtering and ventilation system.

Repair

Polish with Fine Polishing Compound and finish with any standard high-gloss polish. For major problems, sand down completely and apply a new finish.

Seeds

A surface with this defect will show particles of different sizes deposited in the primer or color.

Causes

Various types of contamination typically introduced during the application or drying process.
1. Paint kept in dirty containers/tins.
2. Paint was not strained.
3. Paint has been kept longer than recommended.
4. Activator or thinner used were incorrect.
5. Tintings/pigments were not sufficiently stirred.
6. Use, re-thinned, of 2K materials after the recommended potlife.

How to avoid

1. Care of the maintenance of the equipment.
2. Follow the recommendations (pressure, thinner) to avoid overspray.
3. Mix the color thoroughly after sufficient stirring of tintings.
4. Do not exceed the recommended potlife of 2K materials.
5. Use a fine strainer.

Repair

Polish with Fine Polishing Compound and finish with any standard high-gloss polish. For major problems, sand down completely and apply a new finish.

Sand scratches

Sanding marks in the substrate show as lines in the surface of the refinish paint.

Causes

1. The substrate was sanded with an abrasive that was too coarse. The paint shrinks more strongly in the sanding marks because of the higher film thickness
2. The drying times for the undercoat materials were not observed correctly: The sanding marks are clearly visible due to the swelling of the undercoat materials at the time of painting and the sinkage after drying
3. Filler and topcoat layers were applied too thin to cover the sanding marks in lower layers
4. Wrong sanding technique and/or sanding machines used

How to avoid

1. Use specified grade of sanding paper (P80/P150 for body filler, P240 for primer filler/filler – see relevant technical data sheets). Use guide coat for sanding.
2. Keep to recommended drying times.
3. Keep to recommended film builds.
4. Place sanding machine on surface of paintwork before starting the machine. When dry sanding filler coats, the eccentric stroke should not be greater than 5 mm.

Repair

Denib and refinish using the recommended undercoats and/or topcoats.

Spotting caused by external influences

Physical attack or discoloration of the paint surface due to various causes; the spots take various shapes, colors and sizes.

Causes

1. Tar – Appearance: Dirty, brown-black spots / 2. Industrial waste gas, e.g. SO2 – Appearance: Large area or spot area gone matt (see entry on "Loss of Gloss") / 3. Acid rain – Appearance: No short-term visual effect, but can go matt / 4. Acid (battery) – Appearance: Usually destroys the entire paint build down to the metal / 5. Tree sap – Appearance: Thread-like and droplet shaped, sometimes clear and sometimes brown-yellow marks with swelling / 6. Insects – Appearance: Marks of insect bodies visible in the paint surface / 7. Insect secretions – Appearance: e.g., bee droppings: long yellow-brown marks. Greenfly excrement: round, ring-like etchings / 8. Bird droppings – Appearance: Appearance can vary depending on the type of bird, weather conditions and duration of contamination

How to avoid

Remove all foreign bodies and matter from the paintwork as soon as possible. Wash off tar and tree sap using Wax and Silicone Remover. Remove all other contamination with water. Regular paintwork aftercare is required (washing, polishing, wax protection).

Repair

Depends on the size of damage. For damage to the topcoat, first attempt to polish out the problem using Fine Polishing Compound and finish with any standard high-gloss polish. As a second step, sand the area with P1200 and then polish with Fine Polishing Compound and finish with any standard high-gloss polish. For major damage, sand down to a “sound” substrate and repaint as necessary.

Blistering

In wet weather, a small quantity of water vapor is absorbed into the paint system and will evaporate again in dry weather (osmosis). This process is normal and does not harm a perfectly matched paint system. However, poor processing of the undercoat materials will leave hygroscopic/water soluble substances (salts) behind as contaminants which cause a local concentration of humidity lifting the paint film into blisters. Blisters can occur in many sizes, patterns and frequency and can form between individual layers or beneath the entire paint system. In dry weather, most blisters will recede.

Causes

1. The surface to be painted (filler, bare metal, etc.) was not cleaned thoroughly. Contamination from salt residue, e.g., dirty sanding water or hand sweat, was left on the surface before painting. The blister pattern may indicate the cause (beading = wipe marks, prints = finger or hand prints)
2. Wet sanding of polyester products without sufficient time to allow water to evaporate before application of undercoats and topcoats.

How to avoid

1. Thoroughly clean the areas to be painted with clean tap water. Change sanding and cleaning water regularly, especially in winter when vehicle paintwork is covered in salt. Finally, (depending on the substrate) clean the area with Cleaner, Wax and Silicone Remover or Metal Cleaner.
2. Do not wet sand polyester products, use dry sanding only.

Repair

Sand down the paint system to a “sound” surface. Refinish using the recommended undercoats and topcoats.

Corrosion

Paint damage showing as irregularly shaped blister-like lifting of the paint surface.

Causes

1. Mechanical damage to the paint surface (e.g., stone chips, scratches) causing penetration of moisture to the underlying coats or metal substrate
2. Poor preparation of the metal prior to painting. Insufficient cleaning (see entry on “Blistering”). Poor derusting or poor removal of metal particles left on the surface from sanding
3. Flash rust formation, e.g., on newly sand-blasted surfaces
4. Inadequate or missing cavity sealing (rust perforation)

How to avoid

1. Repair damaged paintwork immediately.
2. Thoroughly clean the metal surface with Metal Cleaner. Remove all rust by sand blasting to produce a bare metal substrate. Tin all welded seams.
3. Prime all sand-blasted areas immediately.
4. Seal and protect all areas as recommended.

Repair

Remove paint system and corrosion (rust) from the affected areas (by sanding, stripping, sand blasting). Clean the area again with Metal Cleaner and Wax and Silicone Remover. Refinish using the recommended undercoats and topcoats.

Craters

Round recesses with a diameter from 0.5 to 3 mm. The appearance ranges from very flat depressions in the final layer of paintwork to serious wetting problems that go all the way down to the substrate. Craters that have been overcoated after inadequate refinishing can become visible again as flat recessions.

Causes

Mainly: Oil, grease, wax and silicone residue (e.g., polishes containing silicone):
1. Humans – impregnated working clothes, rubber gloves, skin and hair care products
2. Spraybooth – lubricants from moving parts, mold release agents from plastic add-on parts, hoses and sealing compounds, poorly cleaned oil and waste water separators, dirty filters in ceiling and floor
3. Paint materials – incorrect use of additives (anti-silicone additive), unsuitable reducers (hardeners) from other suppliers, impurities in the coating due to deficiencies in transport and storage
4. Workpiece – residues from mold release agents on plastic parts, residual drawing agents and lubricants, soldering pastes, bitumen and oil from insulating mats
5. Painting process additives – mold release agents from new sponge cloths, unsuitable cleaning agents and cloths, unsuitable sanding media (scouring cleaners), adhesive from adhesive tapes
6. Environment – aspiration of contaminated air (polishing agent, silicone spray, fine dust, etc.) from other parts of the bodyshop, seals and insulating materials from the building

How to avoid

Items 1-6 list possible sources of cratering. Consequently, various preventive measures to eliminate cratering can be established. As a basic principle, we recommend to use only silicone-free products in paintshops and to thoroughly clean the substrate.

Repair

Sand down the paint system to a “sound” surface. Refinish using the recommended undercoats and topcoats.

Runs

Drips, runs or sags in the paint finish on vertical surfaces.

Causes

1. Hardener/reducer too slow / 2. Viscosity too low / 3. Material or object to be painted too cold / 4. Paint applied too wet / 5. Excessive film builds / 6. Flash-off times too short / 7. Spraygun held too close to the object / 8. Spray nozzle too large / 9. Irregular spraying action

How to avoid

Adapt material, spraygun and spraying technique to application conditions in the workshop. If necessary, clean spraygun and use a smaller nozzle.

Repair

When the paint has thoroughly dried, remove the run with a sanding block, carbon block or wet sanding paper. The finer the paper, the less damage to the paint and the easier to polish. Polish with Fine Polishing Compound and finish with any standard high-gloss polish.

Lifting, sweating, swelling

Swelling and lifting of lower paint layers when new paint is applied. Problem may occur during painting or drying.

Causes

1. Flash-off time too long when working wet on wet with 2K products (gel phase)
2. Recoating of solvent-sensitive layers (NC/TPA) with the wrong repair materials or with excessive film builds
3. Film thickness of sealing coats too low (applied too thin or sanded down too far)
4. Substrate layers not thoroughly drie

How to avoid

1. Always keep to recommended flash-off times.
2.​ Carry out a solvent test and select a suitable paint system.
3. Keep to recommended film builds.
4. Re-dry the substrate, if necessary (e.g., with IR lamps)

Repair

Sand down the paint system to a “sound” surface. Refinish using the recommended undercoats and topcoats.

Bleeding, staining

Diffusion of a soluble dye from the substrate through a paint system. In most cases, bleeding leads to a spot-like discoloration of the topcoat, often producing a reddish or yellowish color shade. Excessive peroxide in a polyester body filler can also cause similar stains due to a chemical reaction with the pigments.

Causes

1. Excessive peroxide from a polyester body filler causes a yellow-brownish stain in the topcoat. Blue and green colors are particularly vulnerable to this problem
2. Soluble dyes from the old paintwork are dissolved by the solvent of the repair materials and thus change the color of the surface.
3. Residues from bitumen and tar.

How to avoid

1. Only use the recommended amount of peroxide hardener for the polyester body filler. Mix hardener and body filler thoroughly.
2. Carry out a solvent test. Soluble dyes have not been used in OEM coatings and in any repair materials for many years.
3. Remove all residues from bitumen and tar before painting.

Repair

To repair areas damaged by “bleeding”, use suitable isolating products, such as Stone Chip and Underbody Protection or Primer Filler, if applicable. In case of major damages, sand the paint system down to a “sound” surface. Refinish using the recommended undercoats and topcoats.

Poor adhesion

Loss of adhesion can manifest itself in two different ways: there can either be a lack of adhesion between the substrate and the whole paint system or a lack of intercoat adhesion (between the individual coats).

Causes

Loss of adhesion can occur when:
1. substances, which can cause adhesion failure, were left on the substrate when it was painted (e.g., silicone, oil, grease, wax, rust, sanding residue, etc.)
2. an unsuitable primer was applied to the substrate
3. the substrate was sanded insufficiently or not at all
4. undercoat or basecoat were applied too dry or too thin
5. drying conditions were not respected.

How to avoid

To avoid loss of adhesion, always use the suitable primer for the respective substrate (e.g., for aluminum or plastic). Apply undercoat materials as specified (in the technical data sheets). Do not apply excessive film builds. Thoroughly clean the substrate before painting.

Repair

Remove all coats with poor adhesion. Thoroughly sand and clean the substrate. Repaint using the recommended undercoats and/or topcoats.

Cracking, aligatoring

Cracks of various lengths and depths.

Causes

1. Inappropriate paint system used on thermoplastic substrates (direct use of polyester body fillers/ fillers, wash primers/ synthetic resin products on TPA) which caused the TPA surface to soften
2. Refinished paintwork insufficiently cured (too little or no hardener used)
3. Inappropriate paint system used: Wash primer overcoated with polyester products Synthetic resin or nitro-cellulose paints overcoated too early
4. Cracks on plastic parts:
5. see entry on "Faults in painting plastics"
6. Exposure to strong UV radiation, extreme temperature fluctuations
7. Flash-off time too short in wet-on-wet process
8. Total film build too high

How to avoid

1. Apply a suitable paint system to the substrate.
2. Ensure correct hardener quantities.
3. Use correct paint system.
4. Plasticize materials.
5. There are no complaints about "cracking" with regard to present automotive refinish products.
6. Respect recommended flash-off times.
7. Check paint system and film thickness of old paintwork and sand down or strip down, if necessary.

Repair

Sand down to the "sound" layers. Refinish using the recommended undercoats and topcoats.

Floating

Spots or stripes of light and dark patches, mainly seen in metallic finishes.

Causes

1. Uneven basecoat application
2. Basecoat flash-off time too short prior to application of clearcoat
3. Basecoat applied too wet or too thin

How to avoid

1. Apply basecoat evenly.
2. Keep to recommended flash-off times.
3. Apply the basecoat as recommended in the technical data sheets

Repair

If clouding/mottling occurs during the application of the basecoat, compensate by spraying a mist coat (basecoat) over the affected area. If clouding/mottling occurs after the clearcoat has been applied, allow to dry, sand down, and repaint.

Chipping, stone chipping

Mechanical damage to the coating due to projected small stones/chippings (e.g., loose gravel).

Causes

Stones are flung onto the paintwork at varying levels of energy (velocity/size). Depending on the impact force, the top layers and also the lower paint layers underneath can be damaged down to the substrate. At the points of damage, humidity will penetrate the coating and lead to corrosion creepback and flaking.

How to avoid

There is no total protection against stone chips. Areas most greatly at risk can be given preventive treatment of additional stone chip and underbody protection (Stone Chip and Underbody Protection black) and/or the use of Softface Additive. An extremely scratch-resistant clearcoat offers protection against small stone chips.

Repair

Stone chips should be touched-up immediately. Refinish using the recommended undercoats and/or topcoats.

Mottling, marble effect

Spots or stripes of light and dark patches, mainly seen in metallic finishes.

Causes

1. Uneven basecoat application
2. Basecoat flash-off time too short prior to application of clearcoat
3. Basecoat applied too wet or too thin

How to avoid

1. Apply basecoat evenly.
2. Keep to recommended flash-off times.
3. Apply the basecoat as recommended in the technical data sheets

Repair

If clouding/mottling occurs during the application of the basecoat, compensate by spraying a mist coat (basecoat) over the affected area. If clouding/mottling occurs after the clearcoat has been applied, allow to dry, sand down, and repaint.

Poor hiding, poor covering

Substrate shows through. Old paintwork or body filler spots: are not hidden by the topcoat.

Causes

1. Color of substrate not matched
2. Color with poor hiding power (e.g., no heavy metal pigment)
3. Topcoat overthinned
4. Topcoat not stirred properly prior to use
5. Paint layers applied too thinly

How to avoid

1. For translucent colors in particular (pearl effects in a three-layer system), a uniform substrate is required.
2. For colors with poor hiding power, use Tintable Filler. Alternatively, use primer filler/surfacer mixed at a level of brightness matching the topcoat, such as Primer Filler black mixed with Primer Filler white, or, with the wet-on-wet method, Non-Sanding Filler dark grey mixed with Non-Sanding Filler white.
3. Stir the paint material thoroughly and thin only as specified.
4. Spray sufficiently thick coats and allow for sufficient flash-off times between coats (solid colors 50-70 µm, metallic effects 15-25 µm).

Repair

After drying, sand down and apply a new finish.

Orange peel

Poor surface texture of the paint finish (poor spray pattern)

Causes

1. Spraygun held too far from object
2. Spray pressure too low (poor atomization)
3. Paint film too thin
4. Viscosity too high (paint too thick)
5. Hardener and/or thinner too fast for the conditions or size of object
6. Spray nozzle too small
7. Flash-off time too long between coats

How to avoid

1. Keep spraygun within the recommended distance from the object.
2. Ensure spray pressure is as recommended.
3. Always apply wet coats.
4. Adjust paint viscosity as recommended.
5. Choose correct hardener and thinner.
6. See tech data for correct choice of spray nozzle.
7. Allow a long enough flash-off between coats.

Repair

For minor problems, sand down with P1200, polish with Fine Polishing Compound and finish with any standard high-gloss polish. For major problems, sand down completely and apply a new finish.

Loss of gloss

Mat or matted paint surface.

Causes

1. Paint sinkage
2. Excessive film thicknesses
3. Weathering (results of the action of sulfur dioxide or nitrogen oxide combined with moisture and/or severe UV radiation)
4. Wrong amount of hardener
5. Poor or incorrect paintwork care
6. Incorrect polishing (polish too aggressive or polished in direct sunlight)
7. Weathered surfaces due to poor paintwork aftercare
8. Car wash brushes too coarse
9. Car cleaning agent too aggressive or concentrated
10. Newly repaired paintwork weathered too early. Thick coats or newly repaired paintwork are sensitive to condensation (below dew point)
11. Insufficient air circulation during drying

How to avoid

1. Keep to recommended film thicknesses. Use the grey shade concept for poor covering colors (yellow/red). The grey shade concept comprises the primer fillers gray, black and white.
2. Ensure regular paintwork after-care.
3. Keep to recommended mixing ratios.
4. Keep to recommended film thicknesses and drying times.
5. Check air circulation, replace floor and ceiling filters if necessary. If in doubt, consult your spraybooth manufacturer.

Repair

First polish with Fine Polishing Compound and finish with any standard high-gloss polish. If the gloss cannot be restored, you need to repaint.

Pinholing

Small holes in the paint surface due to pores and voids in the plastic. This problem often appears on soft flexible parts (e.g., polyurethane rear spoilers) and glass fiber-reinforced plastics.

Causes

Expansion faults or foam holes in the plastic from production

How to avoid

Thoroughly check the plastic part for pores before painting. Then fill the pores using Plastics Body Filler gray.

Repair

Porous paintwork can, in principal, be repaired using the pore filler wiping process. Denib the surface, fill the pores with and refinish the area to be painted. Note: Too many pores in the plastic will make it very difficult to paint. It is important to check the plastic for pores thoroughly before painting.

Water spotting

Mostly light, whitish circular spots/lifting of the paint surface caused by water drying on the surface in combination with lime and salt. The inner areas are normally intact, while the outer edges are slightly lifted.

Causes

1. Insufficient drying of freshly applied coating
2. Excessive film builds are particularly sensitive
3. Wrong amount of hardener

How to avoid

Keep to recommended drying times, film builds and mixing ratios.

Repair

First wash with clean water. If this does not remove the problem, polish with Fine Polishing Compound and finish with any standard high-gloss polish. For major problems, sand down and apply a new finish.