Paint Application Techniques and Standards

Questions and Answers

What is the primary purpose of using an adhesion promoter/mid coat primer?

To provide a protective seal over existing paint

To enhance the gloss of the paint finish

To aid adhesion on hard baked base coat/clear coat finishes (correct)

To increase drying times between paint coats

What is a consequence of short flash times between spray coats?

Improved paint durability

Enhanced paint adhesion

Increased likelihood of paint runs or sagging (correct)

Reduced drying time for acrylic urethanes

Why should the temperature in a spray booth not exceed 100 degrees F between coats?

To lessen the risk of solvent popping and blistering (correct)

To prevent the paint from drying too slowly

To ensure better adhesion of base coats

To avoid causing the paint film to crack prematurely

What effect does a paint flex additive have on the paint film?

Dulls the gloss of the paint when compounded Signup and view all the answers

Which type of paint is noted for its improved durability over plain acrylic enamels?

Acrylic urethanes Signup and view all the answers

What is the maximum allowable paint thickness build-up?

12-14 mils Signup and view all the answers

Which primer is specifically designed to chemically improve adhesion and corrosion resistance on bare metal?

Self-etch primer Signup and view all the answers

What is the typical thickness of original OEM paints?

3/6 mil Signup and view all the answers

What issues can low paint gloss indicate?

Surface irregularities such as checking or micro cracking Signup and view all the answers

What is a common problem associated with a leaking spray gun?

Paint seepage from the gun Signup and view all the answers

What should be applied to all bare metal before using surfacer, sealer, or any other primer?

Self-etch primer Signup and view all the answers

What can cause a spray gun to spatter large droplets of liquid?

Air getting into the paint stream Signup and view all the answers

What type of paint additive is Fish Eye Eliminator primarily used for?

Smoothing paint to address small craters Signup and view all the answers

Study Notes

Paint Application and Problems

Fish eye eliminator enhances paint smoothness by addressing craters or holes in the paint film.
Spot repair foam tape is removed after clear coat application and after the last coat has flashed, ensuring a smooth finish.
Low gloss in paint often indicates surface irregularities such as checking or micro cracking, requiring detailed inspection with a magnifying glass.
Industrial fallout or acid rain causing discoloration must be fully removed before repainting.

Paint Thickness and Standards

Paint thickness is measured in mils (thousandths of an inch); OEM paints typically range from 3 to 6 mils.
Paint build-up should not exceed 12-14 mils to avoid issues in adhesion and appearance.

Metal Treatment and Primers

Immediate treatment of metal substrates is crucial to prevent corrosion.
Auto manufacturers employ a multi-stage zinc phosphate treatment for primer adhesion on metal surfaces.
E coat serves as a paintable primer crucial for factory corrosion protection; it should remain unless manufacturer directs removal.
Self-etch primers improve paint adhesion and corrosion resistance by chemically bonding with bare metal.

Spray Gun Functionality

A spitting spray gun leads to poorly atomized paint, causing large droplets and spattering due to air entering the paint stream or loose parts.
A leaking spray gun can cause paint seepage, often due to dry paint on lid sealing surfaces; maintaining clean sealing areas is essential.

Etching and Sealers

Etching primers should be used on bare metal with surface rust or pits; plain primer may not adequately fill rust pits.
Sealers, available in clear or tinted versions, should only be applied over repaired areas and can help match color with semi-transparent coats.

Adhesion and Flexibility

Adhesion promoter/mid coat primer enhances adhesion on factory baked finishes, preventing lifting and peeling.
Paint flex additives allow cured paint to remain flexible, although they can dull gloss when compounding is performed.

Flash Times and Conditions

Flash times vary based on the type of material, temperature, and humidity; modern urethane and catalyzed products usually recommend flash times of 10-20 minutes.
Cold environments increase flash times while warm conditions can reduce them, but never exceed 100°F between coats.
Excessive flash times can lead to adhesion and flow issues; short flash times may cause running or sagging.

Testing and Spray Techniques

The finger flash test checks if paint is dry enough for additional coats; semi-cured paint will stick to a gloved finger if flashed correctly.
Various spray gun techniques include mist coat, medium coat, full wet coat, and blend coat, allowing for varied finishes in paint application.

Types of Paint

Acrylic urethane is preferred for durability in topcoats, offering improved strength over standard acrylic enamels.
Solid color paints are void of reflective flakes, making them easier to spray and match than metallic or pearl options.

Additional Considerations

Adhesion promoters do not need to be applied over sealed areas, simplifying the preparation process for new paint layers.

Description

Explore essential techniques and standards for paint application, including methods to eliminate defects like fish eyes, and the importance of proper paint thickness. This quiz covers metal treatment, primer applications, and how to ensure a smooth finish in various conditions.