Surface Wetting/Bonding Flashcards
Advantages of Surface Wetting and Absorption
Always clean
Viscosity reduction
Time
Pressure
Disadvantages of Surface Wetting and Absorption
Fingerprints
Incorrect alignment of glue
Low temperature
Incorrect surface pre-treatment
Factors of durable adhesive joint
Mechanical hooking
Must penetrate all cavities prior to curing or trapped air weakens joint
Surface wetting
Sources of contamination on bonding pre-treatment
Fingerprints Dirty cloth Poor degreasing technique Poor chemical solution Other task in the same vicinity (vapours, dust)
Two categories of composite damage
Erosion - abrasions, scratches, nicks, dents
Skin perforation - lightning strike, holes, FOD impact
What is Delamination?
Reinforcing materials separating from each other in the matrix
What is debonding?
Two materials stop adhering to each other
What does BVID stand for?
Barely Visible Impact Damage
Types of damage
Corrosion Erosion Water absorption Chemical degradation Dents/depression
What does NDT stand for?
Non-Destructive Testing
Inspection Techniques
Tap testing
Visual
Bond tester
Ultrasonic
What is Tap Testing?
Detects debonding or trapped water
Like a wood pecker
What is Ultrasonic?
Locates internal defects
Echo is measured
What is Radiography?
X-Ray
Gamma
Three types of repairs
Temporary
Permanent cosmetic
Permanent structural
