C-23 Ornamental Metal exam questions, with answers
10 practice questions for the CSLB Ornamental Metal trade exam, each with the answer, a plain explanation and the source it rests on.
These are not real exam questions. CSLB does not release its test questions or answer keys, and nobody else has them. We write our own questions from the C-23 outline and the codes, standards and references CSLB lists for the exam. Each answer names its source so you can check it.
The C-23 exam has 5 sections. The questions below are grouped by section, with the share of the exam each one carries. Read the question, pick an answer, then open “Show the answer”. The other questions of the free test, scored section by section, are in the free 25-question C-23 test.
Planning and Estimating · 23% of the exam
Reviewing project information; designing ornamental metal products; evaluating job sites; preparing for fabrication; calculating costs.
1. A shop drawing for a balcony railing shows a fillet weld symbol at each post-to-base-plate joint, with an added mark telling the welder to run the weld completely around the post. In the standard welding symbols explained in the Navy's Blueprint Reading and Sketching manual, what is that added mark?
- The field weld symbol
- The flush-contour symbol
- The convex-contour symbol
- The weld-all-around symbol
Show the answer
Answer: D. The Navy blueprint manual says welds that extend completely around a joint are shown with the weld-all-around symbol. The field weld symbol marks welds made later on the jobsite, not in the shop. The flush- and convex-contour symbols describe the shape of the finished weld face, not how far the weld runs.
Source: Blueprint Reading and Sketching (U.S. Navy), welding symbol rules 7 and 8
2. A steel guard on the open side of an interior stair in a single-family house is built under the 2025 California Residential Code (CRC). Under the stair exception in 2025 CRC R321.1.3, and setting aside the triangular opening formed by the riser, tread and bottom rail, what is the sphere size that the guard's openings along the stair must not let pass?
- 3 in
- 4 in
- 4-3/8 in
- 6 in
Show the answer
Answer: C. 2025 CRC R321.1.3 sets a 4 in sphere for required guards in general, but Exception 2 relaxes it for guards on the open side of stairs to a 4-3/8 in sphere. The 6 in value belongs to the separate triangular opening at the bottom rail, and 3 in appears nowhere in the section.
Fabrication · 21% of the exam
Cutting metals; building jigs; forming metals; welding and mechanical applications.
3. You must drill several 1 in holes through a thick steel base plate on the drill press. Why does Army TC 9-524 say to drill a smaller pilot hole first when making a large hole?
- The pilot hole lets the big drill run at a much higher spindle speed
- The big drill's chisel edge scrapes instead of cutting, straining the machine
- The pilot hole lets cutting fluid reach the lips of the big drill sooner
- Without a pilot hole the big drill's margins would harden the steel
Show the answer
Answer: B. Army TC 9-524 explains that as drill size grows, the web and the chisel edge grow too; the chisel edge scrapes rather than cuts, which puts considerable strain on the machine in larger drills. Drilling a pilot hole first removes that load, and the large drill then follows the small hole. Cutting fluid, hardening by the margins and spindle speed are not the reasons the manual gives.
4. The hinge plates on a heavy steel driveway gate are specified with SAE Grade 5 hex bolts. Per Purdue Extension's guide to nuts, bolts and washers, how do you recognize a Grade 5 bolt by its head?
- Six radial lines on the head
- Three radial lines on the head
- No lines or marks on the head
- Five radial lines on the head
Show the answer
Answer: B. Purdue Extension's guide (PPP-158) says a Grade 5 inch bolt has three radial lines on the head, a Grade 8 has six, and an unmarked head means Grade 2; the grade is the number of lines plus 2. Five lines is the mistake of matching the line count to the grade number.
Installation · 20% of the exam
Digging postholes and installing posts; fences, railings, and gates; staircases, stringers, and treads; miscellaneous products.
5. Your crew is installing steel pipe handrails along a sloped concrete ramp at a medical office building under the 2025 CBC. What height above the finish surface of the ramp slope must the top of the handrail be, kept uniform along the run?
- 28 to 32 in
- 30 to 34 in
- 32 to 36 in
- 34 to 38 in
Show the answer
Answer: D. 2025 CBC 1014.2 measures handrail height from the line of the stair nosings or from the finish surface of the ramp slope, and requires it to be uniform, not less than 34 in and not more than 38 in. The 30 to 34 in range in that section is for alternating tread devices and ship's ladders, not ramps.
Source: 2025 CBC 1014.2, 2025 California Building Code (Title 24, Part 2), Section 1014 Handrails
6. You are building a steel pool enclosure for a private single-family home in California under the Swimming Pool Safety Act (Health and Safety Code 115923, printed in 2025 CBC 3109.2). What minimum height and opening limit apply to the enclosure?
- 60 in tall; gaps must stop a 6 in sphere
- 54 in tall; gaps must stop a 4-3/8 in sphere
- 48 in tall; gaps must stop a 4 in sphere
- 60 in tall; gaps must stop a 4 in sphere
Show the answer
Answer: D. Health and Safety Code 115923, printed in 2025 CBC 3109.2, requires the enclosure to be at least 60 in high, and any gaps or voids must not pass a sphere 4 in or more in diameter. The 48 in figure is the federal CPSC guideline height, not the California statute, and the 6 in and 4-3/8 in spheres are guard exceptions, not pool enclosure rules.
Finishes and Repairs · 14% of the exam
Preparation and application; inspecting and repairing.
7. A welded steel tube gate frame with sealed overlapping plates is sent for hot-dip galvanizing with no vent holes. Besides air blocking the cleaning solutions and zinc, what danger does the American Galvanizers Association describe?
- Trapped cleaning solution can flash to steam and rupture the part
- Trapped flux can turn the finished zinc coating a dull dark gray
- Molten zinc can fill the tubes and double the weight of the frame
- Trapped air can chill the zinc and leave the coating far too thick
Show the answer
Answer: A. The American Galvanizers Association says vent and drain holes first let air out so the part is fully immersed and drains; second, without venting, cleaning solutions or rinse water trapped in overlapping or contacting surfaces flash to steam, and the pressure (up to 3,600 psi) can rupture the fabrication. Trapped moisture can also leave uncoated spots.
Source: American Galvanizers Association KnowledgeBase, Venting and Draining
8. Paint is peeling and flaking off hot-dip galvanized railings a few months after your crew painted them. According to the American Galvanizers Association, what are the causes of paint failure over galvanizing?
- Galvanizing too new to paint, or a topcoat applied in direct sun
- Poor surface preparation, or a paint not compatible with zinc
- Steel too high in silicon, or a paint applied with a brush
- A zinc coating too thick, or a primer coat applied too thin
Show the answer
Answer: B. The American Galvanizers Association says that whatever the age of the galvanizing, paint failure over it comes from either inadequate surface preparation or a paint or powder system not compatible with zinc. New galvanizing looks clean but is smooth and needs cleaning and profiling; some paints react with zinc and lose adhesion.
Source: American Galvanizers Association KnowledgeBase, paint failure over galvanizing
Safety · 22% of the exam
Personnel safety; job site safety; loading and transporting material.
9. A welder is torch brazing a bronze ornament onto a steel gate panel. Under Table EP-1 of Cal/OSHA 8 CCR 3382, which filter lens shade numbers are listed for torch brazing?
- Shade 3 or 4
- Shade 6 or 8
- Shade 4 or 5
- Shade 5 or 6
Show the answer
Answer: A. Table EP-1 of 8 CCR 3382 lists shade 3 or 4 for torch brazing (the same as light cutting up to 1 in). Shade 4 or 5 is listed for light gas welding up to 1/8 in, 5 or 6 for medium gas welding, and 6 or 8 for heavy gas welding over 1/2 in.
10. You haul a pickup load of loose steel offcuts and scrap to the recycler on the highway. Under the Vehicle Code rule that the California Commercial Driver Handbook restates (CVC 23114), what is required of the load?
- It must travel in a fully enclosed box or van body on the highway
- It must carry a red flag at the rear when any piece sticks past the bed
- It must be covered or loaded so that nothing spills, drops or blows off
- It must be weighed on a certified scale before it may use the highway
Show the answer
Answer: C. The California Commercial Driver Handbook, citing CVC 23114 and 23115, says it is against the law to drive on the highway a vehicle so covered, built or loaded that any part of its load spills, drops, leaks, blows, sifts or otherwise escapes. The driver may cover or load the vehicle however keeps the load in; an enclosed body is not demanded, and flags and scales are separate subjects.
Source: California Commercial Driver Handbook 3.3.6, Spilling Loads (CVC 23114, 23115)
Where to go from here
How the license works, from experience to fees: how to get a C-23 license. Everything about the course: the C-23 exam page.
Questions from our free C-23 test, written from CSLB License Examination Study Guide, Ornamental Metal (C-23), form 13E-23 (03-2026), for examinations scheduled on or after June 1, 2025. CSLB notes that the percentages are approximate. Reviewed 14 October 2026. Study guidance only; we are not affiliated with CSLB or PSI.