CSLB General Building (B) Trade Practice Test

Câu hỏi luyện tập mẫu

Một vài câu hỏi thực tế từ ngân hàng miễn phí này, kèm giải thích đầy đủ. Dùng công cụ luyện tập ở trên cho toàn bộ.

1. 1. Surface Preparation

   Before repainting a previously painted, chalky exterior stucco wall, what is the FIRST thing a painter should do to ensure adhesion?

   • a.Apply two finish coats without priming
   • b.Wash the surface to remove chalk, dirt, and loose material
   • c.Sand the stucco smooth with 220-grit paper
   • d.Spray a heavy fog coat of the finish color

   Đáp án: b

   Giải thích: Chalk and surface contamination prevent a new coating from bonding. Washing (often with a pressure washer or detergent solution) removes the chalky residue and dirt so the primer or paint can adhere. Painting over an unwashed chalky surface commonly leads to peeling.

2. 2. Surface Preparation

   Bare ferrous (iron/steel) metal should be primed with what type of primer to prevent corrosion?

   • a.A drywall sealer
   • b.A masonry block filler
   • c.A rust-inhibitive metal primer
   • d.A latex wood primer only

   Đáp án: c

   Giải thích: Ferrous metals rust when exposed to moisture and oxygen, so a rust-inhibitive (corrosion-resistant) primer is used to protect the steel and provide adhesion for the topcoat. Block fillers and drywall sealers are formulated for masonry and gypsum, not metal. Surface rust should be removed before priming.

3. 3. Surface Preparation

   When dry-cutting or grinding concrete during prep generates dust, what airborne hazard is of concern under Cal/OSHA?

   • a.Lead only
   • b.Asbestos only
   • c.Respirable crystalline silica
   • d.Carbon monoxide

   Đáp án: c

   Giải thích: Cutting, grinding, or abrading concrete and masonry releases respirable crystalline silica, which can cause silicosis. Cal/OSHA requires engineering controls such as water suppression or vacuum dust collection and, when needed, respiratory protection. This applies to prep work as well as demolition.

   Nguồn: Cal/OSHA Title 8

4. 4. Products & Materials

   Why does a rough or porous surface (like bare masonry) reduce a paint's effective spread rate compared to the label value?

   • a.Rough surfaces repel paint entirely
   • b.The texture and absorption increase the actual surface area and soak up paint, so a gallon covers fewer square feet
   • c.Porous surfaces make paint cover more area
   • d.The label value already accounts for all textures

   Đáp án: b

   Giải thích: Manufacturers' spread rates assume a smooth, sealed surface, but rough and porous substrates have more actual area and absorb paint, lowering coverage. Estimators reduce the assumed coverage for textured or unsealed surfaces. Priming a porous surface first reduces topcoat absorption.

5. 5. Products & Materials

   Which coating type is commonly used to bridge and waterproof hairline cracks on exterior stucco?

   • a.Flat interior latex
   • b.Shellac primer
   • c.Elastomeric coating
   • d.Lacquer

   Đáp án: c

   Giải thích: Elastomeric coatings form a thick, flexible film that stretches to bridge and seal hairline cracks in stucco and masonry while resisting water intrusion. They are much higher-build than ordinary paint. Proper surface prep and film thickness are essential for them to perform.

6. 6. Application

   What is the difference between wet film thickness and dry film thickness?

   • a.They are always equal
   • b.Wet film thickness is measured immediately after application; dry film thickness is what remains after solvents evaporate
   • c.Dry film is always thicker than wet film
   • d.Wet film only applies to spraying

   Đáp án: b

   Giải thích: Wet film thickness is the depth of the coating right after it is applied and is checked with a wet-film gauge. As solvents or water evaporate, the film shrinks to its dry film thickness, which equals wet thickness times the volume solids. Controlling wet film during application is how a painter hits the specified dry mils.

7. 7. Application

   What is the purpose of masking and using drop cloths before spraying?

   • a.To protect adjacent surfaces and areas from overspray and drips
   • b.To slow down the drying of the paint
   • c.To increase the VOC of the coating
   • d.To thin the paint

   Đáp án: a

   Giải thích: Masking with tape, paper, or plastic and laying drop cloths protects windows, floors, fixtures, and neighboring surfaces from overspray, drips, and splatter. This is especially important with airless spraying, which produces significant overspray. Good masking saves cleanup time and prevents costly damage.

8. 8. Application

   Why should airless spray tips be selected based on the coating and orifice size/fan width?

   • a.Tip size and fan width control flow rate and pattern; the wrong tip causes poor atomization, uneven film, or excess overspray
   • b.Tip size only affects the paint color
   • c.All tips spray every coating identically
   • d.Tip choice has no effect on finish quality

   Đáp án: a

   Giải thích: Airless tips are rated by orifice size (flow) and fan angle (pattern width), and they must match the material's viscosity and the surface. A tip too large for a thin coating floods the surface, while a worn or wrong tip causes tails, stripes, and orange peel. Selecting and maintaining the correct tip is key to a quality sprayed finish.

9. 9. Planning & Estimating

   A job requires 18 gallons of paint at $45 per gallon. What is the material cost for the paint?

   • a.$810
   • b.$630
   • c.$450
   • d.$900

   Đáp án: a

   Giải thích: Material cost equals quantity times unit price: 18 gallons x $45 = $810. A complete estimate also adds sundries such as tape, brushes, rollers, and masking. Marking up materials appropriately is part of pricing the job.

10. 10. Safety

    What control best reduces respirable crystalline silica exposure when sanding or grinding concrete?

    • a.Working faster to finish sooner
    • b.Using a household fan to blow dust around
    • c.Wet methods or tools with vacuum dust collection (HEPA), plus respiratory protection when needed
    • d.Sweeping the dry dust with a broom

    Đáp án: c

    Giải thích: Silica dust is controlled at the source using water suppression or tools fitted with HEPA vacuum dust collection, which is the preferred engineering control under Cal/OSHA. Respiratory protection supplements these controls when exposures remain high. Dry sweeping and blowing dust make exposures worse.

    Nguồn: Cal/OSHA Title 8