Power Tooling is a method that can easily used by the crewman on board. Sanders, needle guns, pneumatic chisels and rotary wire brushes are all tools which can be used. The method usually fails due to salts and contaminants left on the steel when coated. Another reason of failure is the coating is not applied thick enough.
Advantage
- Relatively inexpensive for small areas
- Easy mobilization
- Can be done by crew
- Good for localized corrosion.
Disadvantages
- Difficult to remove contaminants
- Time consuming
- Only for smaller areas
Method
- Pressure clean the areas to be treated with at least 200 bar to remove salts and contaminants. This is very important and crucial to a good repair.
- Apply good ventilation so that the surface dries properly.
- Using a power tool, chip or grind away all the loose rust and paint until a clean metal surface is exposed.
- “Feather” the edges of the surrounding coating to prevent lifting of edges – “elephant ears”.
- Remove all the sanding dust from the surface with either clean, oil free compressed air or washing. A second high pressure wash is best.
- Dry the area to be treated properly. Many coatings will not adhere to a damp surface!
- Using a paint brush, not roller; apply the coating, so that the Dry Film Thickness (DFT) is at least 300 microns. (Three to six coats with a paint brush, depending on whether the existing coating is intact).
- Always refer to paint manufacturer specifications for Dry Film Thickness (DFT) and interval times.
