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
Before painting new galvanized steel, what surface preparation issue must a C-33 contractor address?
Answer: Zinc oxide and oils from the galvanizing process prevent paint adhesion
New galvanized steel has a zinc oxide layer and manufacturing oils that repel standard paints. The surface must be cleaned and treated to promote adhesion.
What is the recommended method for testing surface moisture content in concrete before painting?
Answer: ASTM D4263 plastic sheet test or electronic moisture meter
The ASTM D4263 plastic sheet test and electronic moisture meters are the standard methods for verifying concrete moisture content before painting.
When preparing previously painted exterior wood for repainting, what level of surface preparation is typically required?
Answer: Remove only loose, flaking paint; feather edges and sand glossy areas
Standard preparation involves removing loose, flaking paint by scraping and sanding, feathering rough edges, and sanding glossy surfaces for adhesion.
What is the purpose of applying an 'etch primer' to smooth, non-porous surfaces like aluminum or fiberglass?
Answer: To chemically etch the surface and create microscopic adhesion points for the topcoat
Etch primers contain mild acids that chemically react with the substrate, creating microscopic texture and chemical bonds that improve paint adhesion.
A C-33 contractor is preparing drywall with multiple joint compound patches. What preparation ensures a uniform paint finish?
Answer: Prime the entire surface with a PVA drywall sealer to equalize absorption rates
Joint compound and drywall paper have different porosity. Priming the entire surface equalizes absorption, preventing 'flashing' at patch locations.
What does 'profile' mean in the context of surface preparation for industrial painting on steel?
Answer: The microscopic peak-to-valley roughness pattern created by abrasive blasting
Surface profile is the microscopic roughness pattern created by abrasive blasting, measured in mils. It provides the mechanical tooth for coating adhesion.