Clamping dilemma - profiled box

[Ron Hitchcock]

Take a look at the attached picture. I'm using the profile bit in bottom left. I'm trying to clamp up using straps with 90 pieces which slid along. This work great for straight, flat boxes. However, when tightened the corners move. How do you clamp something like this.

Ron269338

[Jim Matthews]

Two pieces of plywood, sized to fit in the opening and covered with Saran wrap (so they won't get glued) would be my suggestion.

You might be able to get away with just one piece, fitted in the top.
Do I guess correctly that when you clamp it, the clamp slides "up" to the narrow end of the profile?

Traditionally, "pinch" clamps (http://theapprenticeandthejourneyman.com/2011/02/03/review-ulmia-miter-clamps-and-pinch-clamps/) which are nothing more than wire springs with a sharp spur are used, but they're expensive.
Your local Michaels Art supply should have something similar.

They won't generate tremendous force, so the joints must be verified in a dry fit, first.

I would glue two pieces at a time, if you're still having trouble - make sure they're square with some sort of clamping guide.
These (http://www.mcfeelys.com/product/JSS-0001/3-D-Square-Precision-Aluminum-Clamping-Corner/?gclid=COCqk9O6mbkCFUui4AodwA8AXQ&ci_src=17588969&ci_sku=JSS-0001&ef_id=Ugyv6QAAAQBNoH@z:20130825204135:s) are the ones I use.

[Steve Jenkins]

Use clear packing tape. Not the fiber reinforced kind just normal packing tape. You can stretch it to get really good clamping pressure.Wrap completely around box several times.

[Randy Walker]

rubberbands and tape ........ my two favorite clamps, need a little more preasure add some stretch wrap. Works every time.

[George Gyulatyan]

Why don't you glue up the box while everything is still flat/squre and then route the profile on the assembled box?

Sorry if I am confused.

[Pat Barry]

Great idea. Reminds me of the semi truck wedged and stuck under the bridge. No one can figure out how to get it out and the little kid comes by and says let the air out of the tires. Brilliant