Here are assemble aids that hold those right angles together until the glue dries or you can secure corners with screws or nails. We recommend the models below.
LEGO Creator Expert Assembly Square (10255)
90 Degree Aluminium Alloy Positioning Squares Right Angle - Temu
How do I remove dried glue from my clamps?
Wise Buys: Right-angle Assembly Squares
Wotendy 2Pcs 90 Degree Positioning Squares, Aluminium Alloy Right Angle Ruler Clamps Woodworking Carpenter Tool Corner Clamping Square for Picture Frame Box Cabinets Drawers, Carpentry Squares - Canada
WETOLS 12PCS Positioning Squares, 90 Degree Right Angle Clamp Woodworking Tools for Handyman, Wood Clamp Square Clamp for Carpenter DIY Pictures Frames, Cabinets, Boxes, etc - WE867
Here's a cute trick for clamping acute angles
Wise Buys: Right-angle Assembly Squares
LEGO Creator Expert Assembly Square (10255)
Wise Buys: Mini-Lathes
Buy VEVOR 90 Degree Positioning Squares, 5.5 x 5.5 Right Angle Clamps for Woodworking, Aluminum Alloy Corner Clamping Squares for Boxes Cabinets
VEVOR 90 Degree Positioning Squares, 5.5 x 5.5 Right Angle Clamps for Woodworking, Aluminum Alloy Corner Clamping Squares for Boxes Cabinets
Homemade Hold-downs
Milescraft 8" ClampSquares - 90 Degree Corner Clamp, Positioning/Assembly Squares (Set of 2) 4011 - The Home Depot
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