Corrosion around the aperture is very serious and must be corrected properly. First, identify the nature and the extent of corrosion present.
The following defines these characteristics:
| Level | Description | Recommended procedure |
|---|---|---|
| 1 Light | Light metal discoloration; typically orange. | Remove corrosion with 180 grit sand paper, wire wheel or Dremel® and a grinding stone. |
| 2 Moderate | Moderate corrosion typically has some red spots. | Remove corrosion with wire wheel or chemical rust remover. |
| 3 Severe | This can be identified by deep “pitting”, dark red spots and raised edges. | Remove corrosion with media blast or chemical rust remover. |
| 4 Perforation | This level can vary from microscopic holes to loss of metal. | The panel must be replaced and treated by a body shop. |
Sika recommends that treatment of level 4 corrosion and any corrosion around the aperture greater than a total of 150 cm2 should only be performed by a body shop trained in metal restoration!
Perforation corrosion located in any structural area, such as the window frame, requires the replacement of the entire section of metal. Areas like these should not be filled with body filler, as glass bonding adhesive will be applied.
Corrosion Removal
Ideally, corrosion removal should be done prior to trimming the remaining well-bonded adhesive bead.
- Remove corrosion
- Use siavlies speed abrasive pad* (very fine) to abrade the intact paint for a further 5 mm beyond the paint edges surrounding the areas where corrosion has been removed
*Available from Sia Abrasives
Corrosion/Bare Metal Treatment
Clean the entire area using Sika® Cleaner G+P to remove dust and dirt
- Apply Sika® Primer-207 using a brush or dauber, making sure the primer overlaps onto the surrounding intact paint by at least 5 mm
- Allow to flash-off for at least 3 minutes and wait until the surface is touch dry
- Apply a second coat of Sika® Primer-207 over the first coat and allow to flash-off for at least 3 minutes before proceeding to the next step