
This is a great idea and they work in some cases, but the inside corner doesn't have much grip so in some cases it can be difficult to hold while gluing/screwing in exactly the right place. It's a lot better than no clamp, though, and at $12 for 4 it'll probably get the job done for a reasonable price.

WETOLS Angle Clamp 2Pcs Woodworking: Precision Tool for Perfect Angles in Woodworking Projects
11 Review

Versatile and Durable: Discover the AmazonBasics 14 Piece Nylon Spring Clamp Set
12 Review

Multitool pliers LEATHERMAN Wave plus (832524/832526) black
17 Review

Optimized Plastic Spring Photography Backdrop Support
11 Review