I needed to claim some space on my pad to practice aggressive inline skating. Last fall, a friend, dropped off some 8020 aluminum extrusions... His work wanted it gone so I gave it a home on my pad where I now want to skate. I knocked the extrusion walls down and recycled some of the material into grind rails for skate training. I've never built with 8020. It was easy and quick. The operation yielded me more pad space and a few new training obstacles. Two birds... One stone. It's not the cheapest solution but a great one in my case. Happy building... Happy skating.