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If you’ve ever tried to build a box from clear acrylic, you know how hard it can be to get good-looking joints between the panels. The folks at TAP Plastics have gotten pretty good at it, but even they admit that the basic slab-joint method “will not produce museum grade products.”

This video was produced by the German firm Serrox Technischer Handel, which sells plastics fabrication products. Unsurprisingly, it promotes a number of their specialized products, but I think the underlying process—which has very much to recommend it over the slab-joint method—could probably be adapted to do without them. It’s a bit difficult to describe in words, so you may save some time just watching the video, but I’ll give it a shot:

  1. 90-degree V-grooves are cut almost all the way through a rectangular sheet of acrylic—one groove parallel to and equidistant from each side.
  2. Strips of solvent-proof tape are applied to the ungrooved side of the plastic—one strip centered over and all the way along each groove.
  3. The plastic is bent and snapped at each groove. The strips of tape have become hinges.
  4. The four small squares of waste plastic in the corners are removed, and a couple bits of interfering tape are cut away with a razor.
  5. The sides of the box are folded up along the hinges. The tape has kept everything exactly in place, so all the miters line up perfectly. Strips of tape are applied at the four corners to hold everything in place.
  6. Solvent cement is applied along the inside of each mitered edge. When it sets, the tape is removed, and the box is complete.

The key process is cutting the 90-degree V-grooves, for which Serrox sells a special V-groove circular sawblade. I am led to wonder, however, if it couldn’t be done just or almost as well with a V-groove router bit, as long as you took steps to keep the cut from getting too hot…

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.


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Comments

  1. Yes Sean it can be done with a 90 deg. Router bit. I do it this sway all the time on the Shopbot but I use just plain old Blue painters tape. Really NO Speciality tools or Chemicals are required to do this.
    You also do the same thing but leave your cut depth shallower and use a heat strip to bend the acrylic into place. Which leaves you with a nice smooth rounded one piece feel.

    1. Thanks, Angus!  Gonna give it a try.  Stand back! =]

    2. Thanks, Angus!  Gonna give it a try.  Stand back! =]

    3. Jimmy says:

      Yeah, Thanks for show in video, I want to make by my selft

  2. Anonymous says:

    That’s a neat technique, and no mistake…

    but i really doubt that from setting up the cuts on the $1000+ radial saw system [not shown] to the last bit of solvent evaporation is a “make a box in 5 minutes” project.   and if one can knock-out/remove the unneeded corner pieces so easily, doesn’t that mean that the hinge joints that are part of the project are rather weak points too?

    1. karnuvap says:

      You’ve got it wrong – those aren’t hinge joints once the plastic has snapped. They only hinge on the tape until the final stage when the plastic dissolving solvent is applied and then the sides fuse to the bottom through a plastic weld.

    2. karnuvap says:

      You’ve got it wrong – those aren’t hinge joints once the plastic has snapped. They only hinge on the tape until the final stage when the plastic dissolving solvent is applied and then the sides fuse to the bottom through a plastic weld.

  3. Anonymous says:

    Great idea until I got a quote back from the distributer for the blade…  $680 for ONE blade shipped to the US.  No thanks…

  4. Anonymous says:

    Great idea until I got a quote back from the distributer for the blade…  $680 for ONE blade shipped to the US.  No thanks…

  5. Anonymous says:

    Great idea until I got a quote back from the distributer for the blade…  $680 for ONE blade shipped to the US.  No thanks…

    1. James B says:

      If you have a table saw you can get a Magic Molder head with a 45 degree Vee insert plug for about half that.  I’ve seen these around for years, but never tried one.

      Or you can set a zero kerf table saw blade at 45 degrees and make two passes in opposite directions.  I would definitely use a sled or miter gauge to feed the material for the second pass.  If you push it along the fence it would likely buckle up, catch the back end of the blade,  and throw your workpiece back into your gut

      http://www.bladesllc.com/magic-molder-heads.html

    2. James B says:

      If you have a table saw you can get a Magic Molder head with a 45 degree Vee insert plug for about half that.  I’ve seen these around for years, but never tried one.

      Or you can set a zero kerf table saw blade at 45 degrees and make two passes in opposite directions.  I would definitely use a sled or miter gauge to feed the material for the second pass.  If you push it along the fence it would likely buckle up, catch the back end of the blade,  and throw your workpiece back into your gut

      http://www.bladesllc.com/magic-molder-heads.html

      1. Anonymous says:

        Assuming you were working with a relatively thin piece of acrylic, wouldn’t the kerf of a normal blade be enough to cut the other half of the 45*?

        1. James B says:

          Twiek, I believe it would, but my kerfless blade is only about an 1/8″ wide, so your material would have to be around 3/32″ would be about the max thickness .  But using this idea, you could use a dado stack and cut much thicker material. 

          I might have to try this:  I think I have some acrylic in the shop, have some blue tape that worked fine with solvent based automotive finishes, and know I have a dado stack.  I  just need some of that capillary action adhesive.  A single pass with a dado cutter would avoid having to try to cut a floppy workpiece, and make it much faster. 

        2. James B says:

          Twiek, I believe it would, but my kerfless blade is only about an 1/8″ wide, so your material would have to be around 3/32″ would be about the max thickness .  But using this idea, you could use a dado stack and cut much thicker material. 

          I might have to try this:  I think I have some acrylic in the shop, have some blue tape that worked fine with solvent based automotive finishes, and know I have a dado stack.  I  just need some of that capillary action adhesive.  A single pass with a dado cutter would avoid having to try to cut a floppy workpiece, and make it much faster. 

  6. karnuvap says:

    Point 4: the excess tape is not cut away but merely sliced along one edge and then but they stay as flaps of tape that are later used in your step 5 to hold the four corners in place.

  7. Anonymous says:

    Good technique Although as Angus has already said router cutter works just fine.

  8. Anonymous says:

    Good technique Although as Angus has already said router cutter works just fine.

  9. V-bit on a router table should work just fine.   Cheap and easy.  This is a good technique but amenable to different approaches.

  10. Scott House says:

    To everyone looking for a V-grooving blade, there is one on e-bay
    starting at $25.00.  It is not my item, and I am in no way connected
    with the seller,  I just did the first thing I usually do, and search
    e-bay for interesting items.  :-)
    http://www.ebay.com/itm/160654664201?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

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