Coating Specification / Visual Review / Sealing Materials

Stand Mai 2013

1.) General 

The paint system must fulfil the required standards in compliance with the prescribed processing guidelines.

2.) Coating Specification

Basically valid is the paint specification confirmed from Krapf & Lex to the customer!

3.) Review of visible areas

The visual review occurs according to the following criteria:

  • View with the naked eye
  • Viewing angle for the detection of surface defects approx. 90° to the concerning surface
  • Light quantity min. 500 Lux
  • The viewed surface should be free from surface reflexions and direct solar radiation
  • Viewing distance approx. 1 metre

In case of visible surface defects the use of supporting tools for the review is permitted (e.g. scale loupe).

3.1) Acceptable inclusions and surface defects coating methods A, B and C in the visible

Components with large surfaces: e.g. doors, flaps (test format DIN A3)

Components with small surfaces, e.g. ventilation grilles (test format DIN A4)

Furthermore inadmissible are:

  • Bubbles, tubulars, scratches, craters, varnish run, slumps, spray shadows
  • Inadmissible surface defects coating methods B and C
  • OVERSPRAY on the top coat layer

3.2) Rating of structure and colour shade in the visible area

Structure and colour deviation according to release pattern approved by the customer.  

3.3) Gloss level in the visible area

Measurement of gloss level according to DIN 67530:  (equipment Elcometer 401Novo Gloss 20°/60°) under consideration that surface structures as for example orange peel in the running manufacturing can influence the measurements

tolerance value + / – 5 GU    

4.) Rating of non-visible areas: (Painting reverse side)

Varnish run, slumps: tolerated except seal- and bolt areas
Inclusions: 10 inclusions Ø 0,5 mm / 4 inclusions Ø 1,0 mm (test format DIN A3)
Overspray tolerated in the area of bars, angels and bridges
Gloss level: no specifications and measurements
Colour shade: colour shade deviations tolerated

5.) Coating Thickness

Coating thickness measurement according to DIN 2360: (equipment List Magnetic Type 5 FN – ST) The single coating thicknesses (anodizing and powder coating) must be measured individually.

The coating thicknesses defined for powder coating and lacquer can only be guaranteed in the outer area of our components, due to their complex geometrical structure.

Independently, the special anodizing procedure always provides for a full and high-grade corrosion protection.

6.) Sealing Materials

Krapf & Lex uses (two) standard sealing materials, which can be used for all products in indoor and outdoor areas. Both materials are coatable and adhesive strength tested.

  • Sikaflex 521 UV  (grey and black)
  • Sikaflex 221  (grey)

For all sealing joints not painted from Krapf & Lex, Sikaflex 521 UV is used.
For Sikaflex 221 and Sikaflex 521 UV we have an adhesive strength test according to DVS 1618 for the following surfaces:

  • Anodized
  • Aluminium blasted
  • Powder-primed with IGP KORROPRIMER 30
  • Powder lacquer Interpon D1036 in RAL 7016 and IGP-HWF 3001, 5903 in RAL 9006

The test reports about the adhesive strength that might be required by use of other sealing materials or surfaces (e.g. powder lacquer) must be additionally calculated.

The company Krapf & Lex does not provide warranty for the adhesive strength of sealing materials which have been defined by the customer. We assume that these have been tested and released by the customer.