Surface Preparation for Various Substrates Flashcards
6 cards from real C33 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Surface Preparation for Various Substrates flashcards as text
When preparing a previously painted surface for recoating, what does the term 'feathering' mean?
Answer: Sanding the edges of peeling or chipped paint to create a gradual, smooth transition to the substrate
Feathering is sanding the edges of intact paint where it meets scraped or peeled areas, creating a gradual taper rather than an abrupt ridge.
A C-33 contractor encounters 'mill glaze' on newly milled wood siding. What is mill glaze and how should it be addressed?
Answer: A burnished, hard surface created by planer blades that resists paint adhesion - sand with 60-80 grit
Mill glaze is a smooth, burnished surface created when planer blades compress and seal the wood surface during milling. It must be sanded to open the grain.
Before painting a concrete floor, what test determines if a previous sealer will prevent paint adhesion?
Answer: Water drop test - observe if water absorbs into or beads up on the surface
The water drop test involves placing water drops on the concrete. If water beads up rather than absorbing, a sealer is present that will prevent paint adhesion.
What is the correct preparation for painting over a glossy, oil-based enamel with latex paint?
Answer: Sand the glossy surface, clean thoroughly, and apply a bonding primer before latex topcoat
Latex paint does not adhere well to glossy surfaces. Sanding, cleaning, and a bonding primer provide the needed compatibility.
When preparing exterior stucco for painting, how should hairline cracks be addressed?
Answer: Fill with paintable elastomeric caulk or use an elastomeric coating that bridges hairline cracks
Hairline cracks should be filled with flexible elastomeric caulk, or an elastomeric coating can be used that bridges cracks up to 1/16 inch.
A C-33 contractor is painting new plaster. How long should traditional lime plaster cure before painting, and what test confirms readiness?
Answer: 30-90 days - test with phenolphthalein indicator or pH strips to confirm pH below 10
Traditional lime plaster requires 30-90 days to cure. A phenolphthalein indicator or pH strips confirm the pH has dropped below 10, making it safe for painting.