I-CAR AWQT common mistakes
I-CAR AWQT · Understand the traps and how to avoid them.
Welding without first verifying the machine's duty cycle and setting a current level the task can sustain, then continuing to weld after the unit's thermal overload trips repeatedly.
Candidates memorize duty-cycle percentages as isolated facts but never connect them to real shop behavior; they treat the rating as a label rather than an operating limit and assume a tripped machine is faulty rather than overloaded.
What to do instead
Before welding, read the duty-cycle rating at the amperage you intend to use and calculate how many minutes of arc-on time per 10-minute period are permitted. If the machine trips, stop, let the fan cool it, and reduce amperage or switch to a higher-rated unit rather than resetting repeatedly.
Selecting shielding gas by habit (whatever cylinder is nearest) instead of matching the gas mix to the process and base metal, such as using pure CO2 or a rich-CO2 mix for thin sheet where spray transfer and low spatter are needed.
Gas selection feels like a minor variable compared with amperage, so candidates skip the reasoning step; exam items that pair a gas with a transfer mode expose this gap.
What to do instead
Build a mental table linking gas mix, transfer mode, and application: argon-rich mixes with low CO2 for thin-gauge sheet and spray transfer, higher CO2 for deeper penetration on thicker steel, and never the steel mix for aluminum. State the transfer mode each mix produces before answering.
Treating squeeze-type resistance spot welding as a single universal procedure and applying the same tip force, current, and hold time to high-strength and ultra-high-strength steels as to mild steel.
Candidates learn one 'typical' spot weld recipe and reuse it; they underestimate how much coating type, steel grade, and stack-up change the required parameters.
What to do instead
For every STRSW item, first identify the steel grade and coating, then look up the OEM-specific weld schedule (current, squeeze, weld, hold, and tip force). Memorize that higher-strength grades generally need different current and longer hold times, and that the OEM procedure overrides any generic chart.
Skipping or shortcutting the weld-through primer and coating preparation step before STRSW, welding directly through e-coat, seam sealer, or adhesive and assuming the weld will still be sound.
Preparation is invisible in the finished part, so candidates deprioritize it under time pressure and do not connect coating contamination to the nugget defects it causes.
What to do instead
Treat surface preparation as a scored step: remove coatings from the weld zone per OEM direction, apply only approved weld-through primer where specified, and verify with a test coupon on the same stack-up before welding the vehicle.
Using MIG brazing wire as if it were a fusion welding filler, running arc-on penetration into the base metal or melting the zinc coating back too far.
The process looks identical to GMAW at the gun, so candidates apply GMAW habits; they miss that brazing must not melt the base metal and that heat input control is the whole point.
What to do instead
Set parameters for the brazing wire and gas per OEM, keep the arc on the wire rather than the panel, use a push or slight drag angle with short stitch beads, and inspect for a smooth bronze fillet with no base-metal melting or undercut.
Identifying steel substrates only by appearance or magnet test and then choosing filler and procedure without confirming the grade from OEM body repair information.
Candidates want a quick physical test, but coatings, galvanizing, and formed shapes make visual identification unreliable, and many modern grades look identical to mild steel.
What to do instead
Locate the specific panel and grade in the OEM repair information before selecting filler, heat, or joining method; use magnet and spark tests only as supporting evidence, never as the deciding factor for high-strength or ultra-high-strength parts.
Attempting to GMAW-weld aluminum with the steel setup - same gun, same liner, same wire, same gas - and then blaming technique when the weld is porous and birdnested.
Aluminum welding looks like steel welding, and candidates underestimate the equipment differences: soft wire, push-pull or spool gun, argon shielding, and dedicated consumables.
What to do instead
Switch to a spool gun or push-pull system with a short liner, use 100% argon and aluminum-specific contact tips, clean the oxide with a stainless brush dedicated to aluminum, and keep wire feed and travel speed higher than for steel.
Joining dissimilar metals by fusion welding without checking whether the OEM procedure permits it, or without a barrier such as adhesive, rivet, or approved transition method.
Candidates focus on making the arc work and forget that metallurgical incompatibility, not operator skill, is the limiting factor.
What to do instead
Confirm the OEM-approved joining method for the specific dissimilar pair (for example steel to aluminum) and default to mechanical fastening or structural adhesive with the specified gap and surface prep rather than attempting fusion.
Judging weld quality only by appearance and passing a smooth, uniform-looking bead without measuring leg length, throat, or performing the required destructive test on a coupon.
A good-looking bead is persuasive, and candidates skip measurement and testing under time pressure; they also forget that some defects such as lack of fusion are invisible from outside.
What to do instead
Use a weld gauge to verify leg and throat against the OEM spec, then perform the specified destructive test (peel, chisel, or twist) on a representative coupon and document nugget size and failure mode before signing off the repair.
Reading a destructive test failure as a pass because the joint held, without classifying the failure mode (interfacial vs. nugget pull-out, ductile vs. brittle) against the acceptance criteria.
Candidates conflate 'it didn't fall apart' with 'it meets spec' and have not practiced mapping failure appearance to defect cause.
What to do instead
Learn the standard failure classifications and what each indicates: nugget pull-out through the base metal generally signals a sound weld, while interfacial separation signals insufficient heat or current. Compare the observed mode to the OEM acceptance criteria and adjust parameters on the next coupon.
Performing a sectioning or repair on a high-strength steel component without checking OEM sectioning locations, heat restrictions, and whether the part is designated as not repairable.
Candidates treat all steel as repairable and rely on general shop practice instead of the vehicle-specific procedure, which varies widely by make and model.
What to do instead
Before cutting or heating, open the OEM body repair manual for that vehicle, confirm the part's repairability designation and any restricted heating or sectioning zones, and follow the published procedure exactly; if the OEM prohibits repair, replace the part.
Wearing the same PPE for all welding processes - for example, using a standard shade lens and no respiratory protection for aluminum or galvanized steel - instead of matching PPE to the process and fume hazard.
PPE becomes routine and candidates stop re-evaluating it when the process, base metal, or coating changes; fume hazards are invisible so they are easy to discount.
What to do instead
Reassess PPE at each process change: select lens shade for the amperage and process, use fume extraction or supplied air when welding coated or aluminum materials, and confirm glove, sleeve, and eye protection ratings before striking an arc.