In this video I walk you through my “Cardboard Kinds Cheat Sheet” and the simple idea that makes cardboard builds look cleaner and last longer: always use the perfect kind of cardboard for the job. I break cardboard down into “styles” (like single face, single wall, and double wall) and “kinds” (the flute sizes like A, C, B, E, plus chipboard). Once you understand that difference, you stop fighting the material and your projects instantly get stronger and more beautiful. I show how single face cardboard bends super easily in certain directions (great for wrapping cylinders and even using the corrugation as a design feature), how single wall is your standard shipping-box material, and why I love double wall when I need thickness and strength—especially because the flutes don’t line up, so it resists bending better. Then we go through the flute sizes: A-flute for big builds that need to support their own weight, C-flute as a common thicker option, B-flute for better detail work, and E-flute when you want fine details and cleaner edges. Finally, I cover chipboard (cereal box cardboard) for tiny details and for covering fluting where you don’t need strength—one of my favorite tricks for making a build look way more elegant.