I've been doing paintless dent repair professionally for about 2 years and my shop owner suggested I get certified. I thought it would be mostly practical, but apparently there's a written component that covers metallurgy and panel materials in real depth.
The aluminum vs. high-strength steel questions are where I'm struggling. I know how they behave differently when I'm working a dent, but explaining the molecular reasons in an exam setting is a different skill.
Is the written portion weighted heavily, or is it mostly a gate to get to the hands-on assessment?
The written portion is a real gate — you need to pass it before they evaluate your hands-on work. Don't skip the materials science sections just because they seem theoretical. About 25% of the written questions touched on metal properties in my exam.
The lighting and tool selection questions are easier to prep for than the metallurgy. Make sure you nail those — they're more straightforward and you shouldn't give away those points.
For the aluminum questions specifically, focus on work hardening and why over-working aluminum causes permanent damage that can't be corrected. That concept came up in multiple forms on the test I took.
Two years of hands-on is solid prep for the practical side. The written material is learnable in 3-4 weeks if you focus. I used a mix of automotive material science resources and the official study guide.
The written part surprised me too, but here's what actually got me through it: every time I got a practice question wrong, I made myself explain why the other three answers were wrong, not just why the right one was right. Sounds tedious. It changed everything though. The metallurgy stuff especially, because the wrong answers are usually things that are true for aluminum but not HSS, or true for cold rolled but not bake-hardened panels. Once you can say "this answer is wrong because that's how aluminum work-hardens, not steel," you actually understand the material instead of just recognizing a phrase you memorized.
It's slower at first, I won't lie. I probably spent twice as long per practice question as my buddy who just drilled flashcards. But when the real exam reworded things or came at the same concept from a different angle, he was guessing and I wasn't. Two years in the field means you already know how the metals behave under your tools, so you're honestly ahead of where you think you are. You just need to connect what your hands already know to the vocabulary they use on the test.