CSLB C-33 Painting & DecoratingCoating ApplicationEasy
A painting contractor is preparing a batch of two-component epoxy primer for application to a prepared metal surface. The manufacturer's technical data sheet specifies a mixing ratio of 4:1 by volume (Part A: Part B) and an induction time of 30 minutes. If the contractor mixes 1 gallon of Part A, how much Part B should be added to ensure the correct ratio?
- A1 gallon
- B0.5 gallons
- C0.25 gallons
- D4 gallons
Show answer & explanationAnswer & explanation
Correct answer: C. 0.25 gallons
A mixing ratio of 4:1 (Part A: Part B) means for every 4 parts of Part A, 1 part of Part B is required. If 1 gallon of Part A is used, then 1 gallon / 4 = 0.25 gallons of Part B should be added.
Why the other options are wrong
- A. This would be a 1:1 ratio, which is incorrect.
- B. This would be a 2:1 ratio, which is incorrect.
- D. This would be a 1:4 ratio, which is the inverse of the specified ratio.
Two-Component Mixing Ratio
The precise proportion by volume or weight in which two components of a coating system must be combined to ensure proper chemical reaction and curing.
- Crucial for coating performance and durability.
- Always follow manufacturer's specifications exactly.
- Incorrect ratios lead to poor cure, adhesion, and film properties.
Memory trick: Ratio's simple, divide and conquer.