The techniques used for surface finishing and painting of aircraft exteriors include:

1. _Chemical Conversion Coating_: A process that converts the metal surface into a corrosion-resistant finish.

2. _Anodizing_: An electrochemical process that thickens the natural oxide layer on aluminum, providing corrosion protection and wear resistance.

3. _Primer and Topcoat Painting_: A high-performance paint system consisting of a primer and topcoat, applied using techniques like spraying, brushing, or rolling.

4. _Specialized Coatings_: Such as thermal barrier coatings, radar-absorbent materials, and protective coatings for specific aircraft components.

5. _Surface Preparation_: Includes cleaning, sanding, and etching to ensure a smooth, contaminant-free surface.

6. _Masking and Taping_: Used to protect areas from paint and ensure sharp edges and lines.

7. _Curing and Drying_: Paint is cured and dried using controlled temperature and humidity conditions.

8. _Inspection and Touch-up_: Final inspection and touch-up of any imperfections or areas requiring additional coating.

These techniques ensure a durable, corrosion-resistant, and aesthetically pleasing finish for aircraft exteriors.