9.4 Part B Practical Exam Preparation
Key Takeaways
- Part B has 46 questions testing hands-on inspection skills using weld replicas and measurement tools
- AWS provides all tools: fillet weld gauges, bridge cam gauge, taper gauge, Hi-Lo gauge, rule
- The bridge cam gauge is the most versatile tool — measures undercut, reinforcement, fillet size, bevel angle
- Always reference the Book of Specifications before making accept/reject decisions
- Read the question first, select the correct tool, measure carefully, then reference the acceptance criteria
- Take full advantage of practice time during the AWS seminar preceding Part B
Last updated: March 2026
9.4 Part B Practical Exam Preparation
The Part B Practical exam tests your ability to apply inspection skills hands-on using weld replicas, measurement tools, and the AWS-provided Book of Specifications. It consists of 46 questions and requires you to make accept/reject decisions based on physical measurements and code criteria.
What Part B Tests
| Skill Area | Examples |
|---|---|
| Fillet weld measurement | Measure leg size with fillet weld gauge; determine if undersized |
| Weld profile evaluation | Identify excessive convexity, concavity, reinforcement |
| Undercut measurement | Measure depth with bridge cam gauge; compare to acceptance criteria |
| Weld discontinuity identification | Identify porosity, cracks, overlap, undercut on replicas |
| Accept/reject decisions | Apply Book of Specifications criteria to measured discontinuities |
| Pipe alignment (high-low) | Measure mismatch with Hi-Lo gauge |
| Root opening measurement | Measure gap with taper gauge |
| Drawing interpretation | Read welding symbols and verify correct weld type, size, location |
Tools Provided at the Exam
AWS provides all necessary tools and materials:
- Weld replicas (plastic reproductions of actual welds with real discontinuities)
- Fillet weld gauge set (standard Cambridge-type gauges)
- Bridge cam gauge (for undercut, reinforcement, fillet size, bevel angle)
- Taper gauge (for root opening)
- Hi-Lo gauge (for pipe alignment)
- Rule / tape measure
- Book of Specifications (acceptance criteria reference)
Part B Strategy
- Read the question first — understand what you are being asked to find or measure
- Select the correct tool — use the right gauge for the measurement
- Take careful measurements — accuracy matters; re-measure if uncertain
- Reference the Book of Specifications — look up the acceptance criteria before deciding
- Make a clear accept/reject decision — based on the criteria, not intuition
- Manage your time — do not spend too much time on any single station
Common Part B Measurement Tasks
Fillet Weld Gauge Use:
- Place the gauge against the weld and the base metal surfaces
- Read the leg size from the gauge
- Compare to the specified minimum fillet weld size
- Check for excessive convexity (gap between gauge and weld face)
Bridge Cam Gauge Measurements:
- Undercut depth: Place the pointer tip in the undercut groove; read depth from scale
- Reinforcement height: Place gauge across the weld; measure maximum height above base metal
- Fillet weld size: Use the fillet weld measurement surface
- Bevel angle: Use the angle measurement feature
Accept/Reject Decision Process:
- Identify the discontinuity type (undercut, porosity, crack, etc.)
- Measure the discontinuity (depth, length, diameter)
- Look up the acceptance criteria in the Book of Specifications
- Compare your measurement to the criteria
- Accept if within limits; reject if exceeds limits
Common Mistakes to Avoid
| Mistake | Consequence |
|---|---|
| Not reading the question carefully | Measuring the wrong feature or wrong weld |
| Using the wrong tool | Inaccurate measurement → wrong decision |
| Not referencing the book | Guessing at acceptance criteria → wrong decision |
| Poor gauge placement | Inaccurate reading → marginal calls become wrong |
| Not checking both legs of a fillet | Missing an undersized leg |
| Rushing | Careless errors on straightforward questions |
For the Exam: Part B is the most practical and hands-on part of the CWI exam. Practice with actual fillet weld gauges and bridge cam gauges before the exam. The AWS seminar that precedes the Part B exam includes practice with the tools and replicas — take full advantage of this practice time.
Test Your Knowledge
Which tool would you use to measure the depth of undercut on a weld?
A
B
C
D
Test Your Knowledge
On Part B of the CWI exam, how many questions are there?
A
B
C
D