Caulk radius tool for keeping a consistent shape on caulked joints. During the construction of a form to pour a concrete countertop I wanted a way to make sure all of the fillets on the edges were the same size and shape, so I quickly modeled and printed this out of TPU. I made each corner a different size so that I could compare and then decide which size(s) I liked best. Ended up using the 5mm radius for the outer edges of the counter, and 7.5mm for the inner edge around the sink. Each corner has the radius debossed, and I rubbed a little black silicone caulk into the text so that it was easier to read. I printed this in TPU as I wanted it to have some flex, but it can probably be printed with any material.

Photos of the form and the finished countertop are included for reference.