Thin acrylic workholding

I’m currently working on a project which requires me to mill some panels from a 12" x 24" sheet of 1/8" cast acrylic. I’ve never milled thin flexible material before and I’m thinking my usual 4 point clamping system will not be sufficient. I’m ordering some double-stick Nitto tape which I’ve heard good things about. However, I’m itching to get started with what I have on hand right now.

Therefore, I’m thinking about using 3M Super 77 spray adhesive to mount the paper-backed acrylic to a piece of sacrificial MDF backer. After searching the archives for “Super 77” I learned that it is not easy to get off of your part, but that shouldn’t be a problem for me since the Super 77 will not touch the acrylic, just the paper backer.

Has anyone tried this? I would love to learn from other’s experience before messing it up myself.

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Adhesives are a popular option:

3M Super 77 adhesive is great stuff, and its use was mentioned here:

You might want to try making a vacuum hold down, plans for that here:

Yeah, it works ok (read the can…follow the directions…don’t ask why I would say that…) on the paper. DON’T put it on the bare plastic though, because getting it off will require solvents that will craze the plastic. The trick with thin stuff like this is keeping it really flat, so be sure your MDF backer is thick enough.

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Would it work to sandwich the acrylic between a couple of sheets of plywood (say 1/8 inch) and cut through the whole affair?


Check out my thread on my dust shoe and you’ll see my method. I create a relief around a board which is then attached to my spoil board. Finally, I use binder clips to hole the plastic down to my board.

Maybe too much trouble for a one-off, though. I keep these on-hand for “standard” sizes of plastic with which I work.


Plywood is so rarely actually flat…

I cut .125in fiberglass and carbon fiber sheets using the blue painters tape and super glue hold down method. Works great and is much much easier to remove the parts and clean up than using double sided tape.


Thanks to everybody for the suggestions. I just tried the painters tape and super glue idea and it worked like a charm.