Based on the Red Seal Welder Occupational Standard & official exam weighting
About the certification
In Ontario, Welder is trade code 456A. The written Certificate of Qualification (C of Q) exam is administered by Skilled Trades Ontario. Welder is a Red Seal trade, so Ontario's certifying exam is the interprovincial Red Seal Welder exam — passing it earns both your C of Q and the Red Seal endorsement. Certification also requires a separate hands-on practical examination in addition to the written test, and certain tasks — welding on boilers, pressure vessels and related piping — require additional certification through the Technical Standards and Safety Authority (TSSA).
The Red Seal exam has 125 multiple-choice questions with a 70% pass mark, both confirmed directly in red-seal.ca's own Exam Self-Assessment Guide for the trade, and candidates are generally allotted up to about four hours. Questions are built from the Red Seal Occupational Standard for Welder.
ExamHub's free 456A practice quiz has 260 original questions across four topic areas that mirror the official exam weighting, with an explanation and a cited source for every answer. It covers the written knowledge exam only — it is unofficial study practice and cannot substitute for the mandatory hands-on practical assessment. Always confirm current requirements with Skilled Trades Ontario.
What's covered
Categories map to the Red Seal exam's Major Work Activity blocks, with welding processes the most heavily weighted — just as it is on the real exam.
Try a few
Five questions pulled from the full bank, with the answer shown — use the quiz above for the real timed experience.
Why: The RSOS ties hand and layout tool maintenance to identifying worn, damaged or defective tools and removing them from service, not passing the problem to the next person or waiting for a full failure.
Why: A bevel is the angled edge preparation that opens up a groove joint so the electrode or wire can reach down to the root of the joint and achieve full fusion, rather than only bridging the surface.
Why: Acetylene burns at the highest flame temperature of the common fuel gases and is the traditional choice for oxy-fuel welding and cutting steel, while argon, CO2 and helium are shielding gases, not fuel gases.
Why: The digits following the E indicate minimum tensile strength in thousands of pounds per square inch — E70XX electrodes deposit weld metal rated at roughly 70,000 psi minimum tensile strength.
Why: Argon is the standard GTAW shielding gas for its stable arc and good cleaning action, with helium sometimes blended in or substituted for its higher heat input on thicker or more conductive metals.
FAQ
The interprovincial Red Seal Welder exam has 125 multiple-choice questions, confirmed directly in red-seal.ca's own Exam Self-Assessment Guide for the trade. ExamHub's practice bank has 260 original questions, and the timed 'Test Me' mode draws exactly 125 questions to match the real exam.
The Red Seal exam pass mark is 70%, stated explicitly in red-seal.ca's Exam Self-Assessment Guide for Welder. On the real 125-question exam that's 88 correct; ExamHub uses the same 70% threshold.
Skilled Trades Ontario allows up to about 4 hours to write a certifying exam. ExamHub's Test Me mode gives you up to 4 hours, which is far more than most people need.
The Red Seal exam weighting is split across four Major Work Activity blocks: common occupational skills, layout and fabrication of components for welding, cutting and gouging, and welding processes — by far the largest single block, covering SMAW, FCAW/MCAW/GMAW, GTAW and SAW.
No. Welder (456A) certification requires a separate hands-on practical examination in addition to the written knowledge exam — a real difference from several other trade quizzes on this site. This quiz only covers the written knowledge portion; it cannot test the practical weld-coupon assessment.
Not entirely. Skilled Trades Ontario notes that certain welding tasks — including work on boilers, pressure vessels and related piping — legally require separate certification through the Technical Standards and Safety Authority (TSSA), on top of the 456A C of Q.
No. These are original questions written by ExamHub from the Red Seal Occupational Standard, Skilled Trades Ontario's Welder trade information, and free CCOHS safety guidance. They cover the same topics but aren't copies of any real exam. CSA and AWS welding standards are paywalled and are not used as a source anywhere in this bank.