BMW April 2022

Paint defects can be caused by a whole range of reasons, from refinishing mistakes to external factors. Here is Glasurit’s advice on how to resolve two of the most common paint defects that painters continuously come across in the automotive refinish industry.

Matching colour correctly

With the great leaps blending techniques have taken over the past years, a perfect paint match isn’t always necessary. However, occasionally a need to paint a panel, such as a bumper fascia, spoiler or air deflector, without blending occurs. When those times arise, having the ability to match a colour is a very valuable asset.

More than likely, vehicles built at the same plant with the same paint code may not match each other or the colour chip standard – usually metallic or pearl colours. Whatever the reason for the differences at the factory level, it’s the job of the painter to make sure the paint matches as closely as possible to the actual paint on the vehicle.

 

A few tips to avoid common paint-matching mistakes:

When matching the colour on a vehicle, to avoid any off-colour issues, make sure you have the right paint formula. Glasurit offers more than one formula for the same paint code. These alternate formulas give you a starting point for mixing the proper colour. For efficient and accurate results, body shops can also use Glasurit’s RATIO Scan 12/6 spectrophotometer as a solution. The spectrophotometer measures colour precisely and takes you to the desired mixing formula efficiently.

Mix the proper alternate per the paint manufacturer’s recommendations.

Agitate the paint for at least five minutes – this ensures that all the tints have been mixed properly.

Choose the right reducer for the air temperature and application – when spraying a metallic color, a slower-drying reducer will create a darker-looking finish.

Use the right gun technique and setup as recommended by Glasurit Technical data sheets. Heavier coats of paint allow the metallic colour to sink to the bottom, giving the paint a darker appearance. Conversely, if applying lighter coats, the paint will appear lighter.

Evaluate the colour in the right light. The last variable to consider before attempting to tint a colour is body shop’s lighting. A colour should be evaulated in natural daylight, when the sun is at its highest point or with a suitable sun gun.

If necessary, tint to match. When all else fails you’ll need to tint a colour to create a match.

Apply the recommended amount of clear. Applying more than the recommended amount of clear will cause light to hit the colour differently, causing a mismatch.

Delamination

Delamination happens if any part of the paint job was done improperly, then all the paint layers are affected. For example, if your car’s metal surface is not prepared correctly from the start, or the primer is not applied correctly, then the base or clear coat will not achieve the correct adhesion to the previous substrate or paint layer.

If a car’s delamination is extensive, then a new paint job. Repainting the vehicle in these cases is more practical and lasts longer than simply repairing the affected area. To repair a delamination, remove the paintwork completely from the substrate and refinish with the correct undercoat and topcoat according to the recommended refinishing system in place with Glasurit. Do not use a paint stripper as this might damage the plastic!

For some models, delamination may not be totally avoidable, but it can be minimised and the paint restored. The best way to deal with delamination is to avoid it by following these pointers

  1. Thoroughly clean the plastic substrate with Glasurit 541-30 Universal Cleaner for Plastics or Glasurit 700-10 Degreasing and Cleansing Agent. If the substrate is very dirty or textured, clean with a sanding pad. Clean the substrate before and after sanding.
  2. Use recommended sanding material. Use a sanding pad, where an irregularly shaped part is to be sanded (for example, radiator grill, bumper etc.).
  3. Clean with Glasurit 541-30 Universal Cleaner for Plastics or Glasurit 700-10 Degreasing and Cleansing Agent. Only these cleaning agents will remove any mould-release agent residues from the substrate.
  4. ‘Heating’ means eliminating the release agents from the substrate by heating the car part (for 1-2 hours at a maximum of 60°C).

Paint defects on a car can be a pain, but most of the time, they’re easily fixed. With a little bit of help from Glasurit any rework done will make the car look good as new.

For more valuable paint help, including troubleshooting advice for other paint conditions, check out the Glasurit Advice on paint defects page on: glasurit.com/za/advice-on-paint-defects.