Aircraft_Finishes.ppt

1、Aircraft Finishes,Ben Fair,Introduction,Reasons for finishes Protection Pleasing appearance These slides give a general overview of information pertaining to aircraft finishes and deal primarily with spayed on paint finishes as well as registration marks.,Finishing Materials,Primer There are numerou

2、s different primers on the market and each has its own characteristics which make it suitable for a specific purpose or process. Types of primers Wash primer Zinc chromate wash primer Primer (is typically an epoxy or urethane primer) Red iron oxide Gray enamel undercoat,Finishing materials (con.t),P

3、aint Types of paint Laquer Easy to apply Easy to repair Can be fuel or chemical resistant May need to be buffed to reach maximum glossiness Enamel Acrylic enamels provide a glossy surface which is very resistant to scratching due to its hardness More care is needed during application Drying time is

4、longer Harder to repair,Paint (cont.),Polyurethane Excellent durability Excellent weather resistance Excellent chemical resistance Typically found in areas where Skydrol is found Should not be waxed Hard to strip,Contents of Paint,Pigment Provides color and durability Also improves the strength of t

5、he paint Binder Holds the pigment in liquid form When applied it then gives the paint the ability to adhere to the surface.,Contents of Paint (cont.),Solvent Effectively thins the paint It carries the pigment and binder Used to regulate how much a paint flows Called a “thinner” when used with lacque

6、r Called a “reducer” when used with enamel,Contents of Paint (cont.),Additives Compose only a small percentage of the paint Used to alter the physical and chemical properties of the paint Provide a more glossy appearance Speed drying time Improve chemical resistance Improve strength Improve corrosio

7、n resistance Improve the appearance of the paint Metal flake Improve weather resistance,Spray Paint Equipment,Spray booth & exhaust systems Used to contain fumes and keep the air around the aircraft clean Compressed- air system Spray guns Electrostatic Gravity fed Siphon fed Pressure fed,Spray Equip

8、ment Classification,Airless spraying Paint solely is forced out under pressure and atomizes after exiting the paint gun. Air spraying Paint is delivered to the paint gun by means of the previously discussed gravity, siphon, or pressure means and then atomized in the paint gun by the pressurized air

9、that forces it out.,Spray Equipment Classification (cont.),Electrostatic attraction The paint gun applies a high-voltage electrostatic charge to the paint particles as they exit the gun. These charged particles are then drawn to the object being painted which has been grounded.,The Painting Process,

10、Paint removal Chemical stripping Dry stripping Sanding Corrosion protection Care must be taken to prevent future occurrences of corrosion For instance a wash primer should be used in the presence of sufficient humidity to ensure there is no left over phosphoric acid which wasnt neutralized by moistu

11、re in the air. In this case this will case filiform corrosion.,The Painting Process (cont.),Surface preparation Conversion coatings Aid in preventing corrosion and also roughen the surface for better paint adhesion Wash primers Used to aid in corrosion protection but primarily for helping with paint

12、 adhesion Top coating The different types of paint can have vastly different properties For example enamel dries slower than lacquer thus a cleaner environment may be required to keep contaminates from destroying the paint job Care must be taken to only use paints and primers which are compatible wi

13、th each other,Common Paint Problems,Runs / sags Starved / thin film Dry spray or texture Blisters or bubbles Blushing (paint is cloudy or milky) Crazing (fine splits or small cracks) Fish eyes (small “craterlike” openings) Orange peel (irregular surface like an orange) Peeling (loss of adhesion) Pin

14、holes (small holes in the layer of paint),Registration Marks,Registration marks are also considered a part of an aircrafts finish due to its required permanency. Registration marks are required by FAR Part 45 Registration and nationality markings are required for aircraft flown in the US. The acceptable location for the marks is specified and different for fixed-wing and rotorcraft. The size of the markings is also regulated.,Pictures,Paint Gun,The start of a