Surface PreparationCâu 18 / 100
Knots and sap streaks in bare softwood can bleed through paint unless they are sealed with what?
a.A thin coat of water
b.Only the finish paint
c.A stain-blocking primer (such as shellac-based or a dedicated knot sealer)
d.A coat of clear caulk
Giải thích
Resin and tannins in knots and sap can bleed through ordinary paint, leaving yellow-brown stains. A stain-blocking primer, often shellac- or oil-based, seals the knot so it does not discolor the finish. Spot-priming the knots before the full prime coat is common practice.
Luyện miễn phí toàn bộ 100 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- New galvanized (zinc-coated) steel often needs what preparation before painting to avoid adhesion failure?
- When patching a larger hole in drywall, why is joint compound often applied in multiple thin coats rather than one thick coat?
- What is the main reason to remove dust after sanding and before painting?
- Why should exterior wood be checked for moisture content before painting?
- What is 'feathering' when preparing a spot repair on a painted surface?
- When dry-cutting or grinding concrete during prep generates dust, what airborne hazard is of concern under Cal/OSHA?
Cập nhật gần nhất: · quy trình kiểm tra
Đội Ngũ Biên Tập PrepPass · Đối chiếu với California CSLB C-33 Painting & Decorating Trade Exam · Quy trình kiểm tra