Re: How to clamp a corner frame ?
The best thing to do would be to remove the window and do the work on the ground.
If you're doing the work with the glass intact, then a simple ratchet strap will hold things together. Apply the glue, install the ratchet strap around the frames perimeter with a piece of paper between it and the glue joints, and snug it down. Use a hammer and block of wood to help drive (tap ) the corner together as the strap is tightened.
Another method would be to build a clamping jig. Again, this would be done with the window from on the ground.
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