Question 801595
I'm am building a frame  out of wood for a canvas that im going to stretch over it to paint,I am wondring since the frame is 8 feet by 2. is there a better way to straighten the frame , other then four triangles  in the conners? ( so to sum it up, would  it help putting bars horizontal or vertical  also in side the frame )
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The problem with rectangular frames is that the joints flex and make them parallelorgrams.
Using stringers, wires (with turnbuckles if needed), on both diagonals is the easiest fix.