CCT CCT Surface Preparation & Bonding Techniques 1 — Questions and Answers
Question 1: What is the primary purpose of surface preparation before bonding composite parts?
- To increase part weight
- To improve adhesion by removing contaminants and creating surface energy (Correct answer)
- To add color to the composite
- To reduce cure time
Correct answer: To improve adhesion by removing contaminants and creating surface energy
Surface preparation removes contaminants and increases surface energy to maximize adhesive bond strength.
Question 2: Which solvent is commonly used to clean composite surfaces before bonding?
- Water
- Motor oil
- Methyl ethyl ketone (MEK) or acetone (Correct answer)
- Hydraulic fluid
Correct answer: Methyl ethyl ketone (MEK) or acetone
MEK and acetone effectively remove oils, mold release agents, and other contaminants from composite surfaces before bonding.
Question 3: What does peel ply leave behind when removed from a cured composite surface?
- A smooth, glossy surface
- A textured, chemically active surface ready for bonding (Correct answer)
- A wax coating
- A painted finish
Correct answer: A textured, chemically active surface ready for bonding
Peel ply creates a textured, resin-rich surface that is chemically active and ready for secondary bonding without additional abrasion.
Question 4: What is the purpose of abrasion sanding during composite bonding surface preparation?
- To remove fiber reinforcement
- To create mechanical interlocking sites and increase surface area (Correct answer)
- To apply primer
- To check surface flatness
Correct answer: To create mechanical interlocking sites and increase surface area
Abrasion sanding creates microscopic mechanical interlocking sites and increases surface area, improving mechanical adhesion of the bond.
Question 5: How must aerospace film adhesives typically be stored to maintain their properties?
- At room temperature in a sealed container
- In a freezer to prevent premature cure (Correct answer)
- In direct sunlight
- At elevated temperature
Correct answer: In a freezer to prevent premature cure
Aerospace film adhesives are stored in a freezer to halt the cure reaction and preserve their tack and mechanical properties until use.
Question 6: What is the purpose of applying a primer to composite surfaces before adhesive bonding?
- To add structural weight
- To enhance adhesion, corrosion resistance, and chemical compatibility (Correct answer)
- To change the composite color
- To increase laminate thickness
Correct answer: To enhance adhesion, corrosion resistance, and chemical compatibility
Primers enhance adhesion between the adhesive and substrate, provide corrosion resistance, and improve chemical compatibility for a durable bond.
CCT CCT Surface Preparation & Bonding Techniques 1
What is the primary purpose of surface preparation before bonding composite parts?