MST Hull & Fiberglass Repair Flashcards
6 cards from real MST practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 MST Hull & Fiberglass Repair flashcards as text
What is the correct ratio of hardener to resin when mixing standard polyester laminating resin for a fiberglass repair?
Answer: 1–2% MEKP by weight
Standard polyester resin requires 1–2% methyl ethyl ketone peroxide (MEKP) catalyst by weight for proper cure.
Before applying a fiberglass patch, the damaged area should be ground to what profile?
Answer: A feathered 12:1 taper
A 12:1 taper grind ensures adequate bonding area and distributes stress across the repaired laminate.
Which type of fiberglass cloth is preferred for above-waterline cosmetic repairs due to its smooth surface finish?
Answer: Plain weave cloth
Plain weave fiberglass cloth sands to a finer, smoother finish and is best suited for cosmetic above-waterline repairs.
Osmotic blistering on a fiberglass hull is caused primarily by what process?
Answer: Water migrating through the gel coat into the laminate
Osmosis occurs when water molecules permeate the gel coat and react with water-soluble compounds in the laminate, forming acidic fluid-filled blisters.
When repairing an osmotic blister, what is the first step after opening the blister?
Answer: Allow the hull to dry thoroughly for weeks
The hull must dry completely — often for 30–90 days — before epoxy barrier coat is applied to prevent moisture from being sealed in.
What material is commonly used as a structural core in modern fiberglass boat construction?
Answer: End-grain balsa
End-grain balsa is widely used as a sandwich core because it is lightweight, rigid, and provides excellent compression strength perpendicular to the grain.