Suggestions to hold down 7" x 12" Concaved Seat

[BTP]

Guys, I am going to be cutting a logo out of the back of a chair.

The wood is 7" x 12" with a concave (like a very flat "U" shape)

I have got the cutout correct , but only have 1 shot to get the sample correct.

any suggestions on how to hold it down?


The cutout will be 3.5" x 3.5" directly in the center.

[tomwillis]

Alex - I've shaped PE foam to the reverse of my part, squeezed the part into the foam and then secure both by vac and clamps.
Tom

[jerry_stanek]

I would cut 2 strips of wood that is just a tad taller than the seat and a couple inches longer screw them to the table and double tape the seat to them

[donek]

wrap it in plastic
clamp firmly to a flat surface with some sort of liner(plastic or paper) on it.
squirt insulation foam into hollow under part and let it dry
separate parts
cut the center of the foam out leaving a vacuum cavity
place foam and part on vacuum table and pull vacuum
start cutting

[BTP]

Guys thanks for the suggestions.

what I ended up doing was recreated the piece with bent plywood. Then clamped to it.
There was a small bit of "play" as you can see from the cut.
BUT, it was good enough to send to the corporate office as a sample.
This is for a chain of restaurants.

Mold I made
http://www.talkshopbot.com/forum/attachment.php?attachmentid=18537&stc=1&d=1376074911

Cutout
http://www.talkshopbot.com/forum/attachment.php?attachmentid=18536&stc=1&d=1376074902


I used a 1/4" double compression bit because its a double sided veneer. I did not even do this with 3D, because I have not played with the software yet.

[knight_toolworks]

the best way I have found is leave wings on each side or each end of the peice. then it gives you a flat surface to fasten it on both sides. the only bad part is it takes extra material.