I know it’s pretty basic, but I haven’t done it since school years ago.
Right now I’m working on a part that I’d like to build in 3d with foam core to mockup a point of rotation. I’ve got the sides cutout and bands to wrap around it, but I can’t figure it out aside from taping it, or perhaps tossing in some foam core ribs to help everything stay square(ish).
Any foam core masters out there have any helpful hints?
I create a lot of foam core boxes for hanging wall art. I cut 2 slits almost all the way through to the second sheet, 1/8" apart and remove the foam core in that gap with an X-acto knife. Then I press both edges so that it appears 90 degrees like in iab’s post and the foam will fold easily. I use a small amount of gorilla glue and set it for a few hours. This will make very solid corners, though I haven’t tried it to make a complete box.
The 2 side flat pieces cut to shape with a 3/16" rabbit cut along the entire perimeter.
The center section is a strip the same length as the perimeter. Kerf cut it on the inside face every 1/8" or so to create the curves. Obviously no reason to do the kerf cuts on the straight portions. Hot glue it to the rabbit cuts.
another great trick is to apply a light amount of gasoline to the inside. this will dissolve the glue and allow you to remove the paper thus allowing you to do smooth beautiful bends with out any creasing!
The rabbet cutter I mentioned above only works with straight edges. I would cut the profile shapes out of foam core and make the connecting strip with white poster board. It will match the white on the foam core and is much easier to work with.