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Acrylic Cheat Sheet: How to Cut, Glue, Bend, and More

Acrylic is a wonderful plastic that can be used for all sorts of different projects. It comes in both transparent and colored options, and can be machined, laser cut, or heated and bent into almost any shape.

Types of Acrylic

Acrylic comes in two varieties: extruded and cast. While they may look identical, there are reasons you may choose one over the other based on your fabrication plans.

Extruded

Extruded acrylic has a lower melting temperature than cast acrylic, which makes it ideal for vector cutting on a laser cutter. This same property, however, makes it less ideal than cast acrylic if you are milling or drilling it.

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Cast

When laser engraving, cast acrylic is preferred, as the resulting engraving will be a frosty white color that contrasts against the rest of the acrylic. Laser engraving extruded acrylic will result in a clear engraving that doesn’t contrast as well.

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Working with Acrylic

Flame Polishing

flamepolishIf the edge of a cut piece of clear acrylic is frosty, and you’d like to make it clearer, it can be flame polished. While it takes some practice to get right, slowly brushing the flame from a propane or MAP gas torch across the edges to melt them slightly can give them a transparent, polished appearance. Just be sure not to polish edges that must be glued, as the resulting joint may not be as strong.

Bending

bending

Using a strip heater, acrylic can be heated and bent at different angles. Store-bought strip heaters can be quite expensive, but there are ways to make do without them. If you have a toaster oven, set it to about 200º and leave the door slightly ajar. Place the part of the acrylic to be bent just above the open door, wait for it to soften enough, and then bend it to the angle desired. If you don’t have a toaster oven, you can (carefully!) use a heat gun to heat the acrylic. When using these makeshift methods, bend the acrylic against the edge of a piece of wood or metal for straight, clean corners.

Bending Small Pieces

bendingsmallIf you’re bending a small, thin piece of acrylic, you can use the shaft of a soldering iron as a primitive strip-heater. Place the iron handle-first into its holder, plug it in, and then use a set of third hands to hold the strip just above the iron. Make sure you keep an eye on it, as you don’t want the acrylic to droop onto the soldering iron.

Cutting

cuttingacrylicFor straight cuts in acrylic, a plastic-scoring blade can be used. With a straightedge as a guide, pull the blade toward you, leaving a score mark. Score the acrylic several more times along the same line, then place the acrylic on the edge of the table and use light, quick pressure to snap the piece in two.

You can also cut acrylic with more traditional blade tools such as a jigsaw, band saw, or table saw. High tooth-count plastic-cutting blades are available for these tools, and are recommended.

SBacrylic

Gluing

Acrylic is typically glued using solvent-based glues, such as Weld-On 4. Unlike many other gluing processes, acrylic glue softens the surfaces of the acrylic and welds them together, chemically bonding the two pieces into one.

To glue acrylic with solvent glue, typically a squeeze-bottle applicator with a needle tip is used. Put the acrylic on the edge where you want it, and place the needle of the glue-filled applicator where the two pieces meet. Lightly squeeze the applicator while pulling it toward you. Capillary action will draw the glue into the joint. Hold the pieces in place for several minutes (a jig with clamps works great for this), and then allow the glue to set for 10–15 minutes before moving it. After 24–48 hours, the joint will cure to full strength.

acrylic solvent

Using solvent-based glues on laser-cut extruded acrylic can cause cracking due to the internal stresses from temperature differences in the acrylic. To guard against cracking, place the acrylic on a flat sheet of glass in a shop oven (not the one in your kitchen!) at about 180ºF (82ºC) for about 1 hour per mm thickness, then let them air cool. This will anneal the acrylic and relieve the built up stress.

Drilling

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If you try to drill a sheet of acrylic with conventional metal or wood drill bits, there’s a chance you’ll end up cracking it. If the sheet is thin, use a step drill bit instead. If you’re working with a thick piece of acrylic, you can use conventional drill bits if you first place a piece of masking tape over the area to be drilled. If the hole is especially thick, spray some WD-40 to act as a lubricant. This will help remove chips and dissipate heat as the hole is drilled.

12 thoughts on “Acrylic Cheat Sheet: How to Cut, Glue, Bend, and More

  1. I’ve tried a couple of different drills on 4 mm acrylic and this is my experience:

    Keep speed low. I used around 800 rpm when drilling as that was the lowest speed on my drill press.

    Don’t be afraid to let your drill bit cut. The material that is removed transports heat away from the drill bit. If you cut too slow the acrylic will melt resulting in an ugly hole. If you cut too fast (especially with big drill bits) the work piece will crack. Test on a scrap piece first. If you do it right you get nice long milky white shavings. Too slow cuts will produce sticky melted stuff around the hole.

    For holes smaller than 4 mm you can use an ordinary spiral bit for metal. You don’t have to press hard as the drill bit cuts quite aggressively.

    For holes 4 mm and up I recommend using a drill bit for glass and ceramic tiles. I’ve found that ordinary concrete drills works pretty well too. I’ve successfully drilled holes up to 12 mm at 800 rpm.

    If you want to go bigger you will need to decrease the rpm to 400 or even less. You may also need to rethink your choice of drill bits but that’s is outside my current experience.

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    2. Thanks for the comment! We’d like to potentially use your for our Reader Input section in the next issue of Make: Can you send me an email with your name and location (city and state) to ccouden [at] makermedia [dot com? Thanks again!

  2. Great Comments. I do disagree with one of them however. I’ve had much better results laser cutting cell cast acrylic as opposed to to extruded. Much cleaner edge, much more consistent density of the product.
    Thanks for the informative article!

  3. My problem with scoring and snapping the acrylic is that invariably the last little bit of the break wanders off the score and doesn’t do the break properly (I have the same problem with glass. Is there any tricks to make the score complete – or am I just not getting the score done properly in general….. Thanks!

    1. Possibly where it’s not breaking cleanly is where you start the score? Make sure when you score to make the knife slide off the glass/acrylic. On glass only score once….when scoring apply enough pressure so you can hear a real gritty/crunching sound….I hope this helps.

  4. One
    thing that the author does not mention is, when drilling thicker
    acrylic with a conventional twist drill, use an abrasive stone parallel
    to the drill to remove the sharp cutting edge of the bit. This allows
    the bit to actually scrape through the acrylic without grabbing and
    ruining the work piece.

  5. If you want to make a hole in acrylic, you’re better off melting the hole through rather than drilling. I heat a coat hanger and make the whole with that. You can shave the blobby edges off with a razor blade.

  6. They also make acrylic drill bits that have a steeper cutting angle which will cut the acrylic instead of melt it as normal ones do. Unfortunately they only go down to 1/8″ diameter. You can get them at McMaster.com individually or as a set. If you drill a smaller hole and then put wax on a larger bit and drill, it will make a less frosted hole. The same with tapping holes, wax will result in a better finish.

    There is also a #3 glue which is slower setting but less likely to cause crazing. It’s also less likely to leave marks if it drips on your acrylic while gluing. #16 is a thick gel version of #3.

    When flame (or abrasive) polishing, sanding out the deep saw marks will not only make it easier to polish but will give better results. Although flame polishing will make the edge clear, it won’t make it smooth. You’ll just end up with clear saw marks.

    An important note when designing for acrylic: the standard manufacturing tolerances for thickness is extremely wide. It’s +/- 30% in cast acrylic and +/- 10% in extruded. So if you want to use tab/slot assembly, you definitely need to measure your sheet, and in some cases, may have to cut the tab part, measure it, then cut the slot part. It’s extremely frustrating.

    1. Hi there, we’d like to potentially include your comment in the Reader Input section of an upcoming issue of Make: magazine. If you can email me at ccouden [at] makermedia [dot] com, we’d like to include your full name and location. Thanks!

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Technical Editor at Maker Media. Maker. Hacker. Artist. Sometimes Scientist. Pretengineer. Builder of things. Maker of stuff.

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