The Tin Wall is a building-block with a dark red pumice-like surface welted in a grey metal-like frame on 2 sides and a grey surface with 2 parallel light-grey straps on 4 sides. It can be crafted in your Crafting Menu (default key "Q") or at Crafting Tables (that still exist in worlds created before R22 on September 16th 2015), but only after the recipe has been unlocked upon taking/crafting Dark Stucco Wall for the first time, which is unlocked by Stucco Wall made by Canyonstone. To craft 8 (blocks of) Tin Walls at a time, you'll need (as of R29 in February 2016):