Aircraft Dope and Thinner Identification

Dope Thinners

• TT-T-266C test determines whether dope is nitrate or butyrate
• Nitrate dope softens immediately when tested, whereas butyrate does not
• Dope thinners can be used in both butyrate and nitrate dope, but nitrate thinners cannot be used in butyrate
• Acrylic lacquer thinner can be used in both butyrate and nitrate dope, but is not recommended
• Butyrate thinner cannot be used to thin acrylics

Retarder

• Retarder is a special type of thinner with rich solvents that dry slowly
• Prevents temperature drop that condenses moisture and causes blushing
• Used in place of regular thinner in high humidity conditions

Anti-Blush Thinner and Acetone

• Anti-blush thinner used in airshow-quality fabric finishes
• Acetone is a universal solvent and cleaner
• Used to remove lacquer finishes and for clean-up after painting
• Softens acrylics or lacquers that have set-up in spray guns or hoses, but has little effect on polyurethane
• Only use virgin acetone, as recovered acetone can be acidic and damaging

Spot Putty and Sanding Surfaces

• Nitrocellulose spot putty used to fill cracks or low spots in wood skins before covering with fabric
• Ensure defects that may cause loss of structural strength are not covered up and hidden

Finishing Equipment and Safety

• Safety is a primary concern in the shop
• Proper storage of paint and chemical strippers, electrical outlets, personal protection, and fire safety are major concerns
• Knowledge of equipment and tools available increases safety and ease of workload
• Maintenance technician should be familiar with paint shop facility, tools, and equipment required to finish the job safely and professionally

Paint Room

• Ideally, paint rooms should be equipped with vapor-proof lights and controlled temperature and humidity for optimum spraying conditions
• Fumes are heavier than air, so place fans near the floor
• Fans should be belt-driven with motors located in areas free of potentially explosive fumes
• Wear proper masks and breathing equipment while spraying paint
• Protect skin from direct contact with chemicals and paints

Air Supply

• Adequate air supply is crucial in a paint shop with conventional high-pressure spray guns
• Air must be free of oil and water, and have sufficient pressure (typically 150 psi)
• Air is stored in a receiver and piped to the paint shop, then filtered and regulated before use

Painting and Spray Equipment

• Newer methods include:
  • High Volume/Low Pressure (HVLP) spray systems
  • Electrostatic paint spray systems
  • Powder coating systems
• HVLP systems produce over 20 cubic feet per minute of atomizing air at less than 10 psi