Need Help Measuring Your Plastic?

As with any material you need to be able to make accurate measurements of your acrylic or polycarbonate sheets in order to employ them to maximum effect. Once you receive your plastic sheet though it may not be clear to you what the best way to proceed is in order to make sure you wind up with the segments necessary to fulfil your needs. Obviously, the more accurate your measurements the cleaner and more precise will be your cuts and the cleaner and more precise will be the joins between panels or between plastic sheets and adjoining walls or other elements.

For Large Scale Installations

When installing plastic sheets, whether acrylic or polycarbonate, over existing walls in a protective manner or over and between existing walls for protective, decorative or structural purposes you’ll typically want to measure the largest piece first. That would be any one which needs to fit between walls. When measuring this sheet you’ll need to leave a 2 to 3 mm gap on each side to ensure a snug but comfortable fit. When they’re in place the adjoining sheets will cover the gap effectively.

When measuring acrylic or polycarbonate sheets that are to join in a corner make sure you allow 6-7 mm (or whatever the precise thickness of the adjoining sheet) so that the adjoining sheet can mate seamlessly. If the space where the sheets are being installed is less than perfectly square make sure you make precise measurements of it and then map them out exactly on the sheet to be cut.

Making Accurate Measurements for Tap Holes

If you’ll be needing tap holes they are measured to the centre of the hole, not the perimeter. You then measure outward from the centre to get the proper diameter in the proper location.

Marking Methods

Once you have made your measurements you’ll need to indicate the cutting or drilling location with absolute accuracy to ensure proper joins, airtight seals and/or structural integrity. There are several methods for marking acrylic and polycarbonate sheets, some of which are low-tech and some of which are high-tech.

  • A magic marker and straight edge - The oldest and most common method for indicating measurements on a sheet of acrylic or polycarbonate plastic is to use a straight edge and magic marker. While this method is fairly dependable the width of the marker line may not lend itself to yielding the exacting cuts you need for a particular application. Still, for most purposes this method has been effective for many years.
  • Razor knife and straight edge - In order to achieve a high degree of accuracy with a mark and to provide a guideline for the cutting tool to follow some prefer to use a razor knife instead of a magic marker. This way the cutting line is etched into the surface of the sheet with pinpoint accuracy. The downside of course is that, should the knife waver even a bit as you’re using it to indicate the cut line you’ll wind up with a scratch you won’t be able to fix. So this method requires an extremely steady hand, an extremely steady surface and plenty of patience.
  • Lasers - Lasers are being employed more and more often these days as a way to ensure absolute accuracy of measurements and cutting lines. A fibre laser for instance allows you to cut many different types of commercial plastics including acrylic and polycarbonate sheets. Typically however lasers are reserved for repetitive measurements and cuts needed for large batch orders, rather than for individual applications.

Other Things to Consider When Working With Acrylic and Polycarbonate Sheets

Both acrylic and polycarbonate are wonderfully versatile materials that you no doubt encounter in some fashion nearly every day of your life. Both are available in either a clear or coloured state and both are fairly heat resistant, durable and, to greater and lesser degrees, pliable. Both can also be effectively machined, measured and cut using a variety of methods.

Acrylic

There are 2 major types of acrylic: extruded and cast. Each has its particular strengths and preferred applications.

  • Extruded Acrylic- Extruded acrylic typically has a lower melting point than does more common cast acrylic. As such it can be a better choice than cast acrylic when you need to produce a high number of pieces which you plan to cut with a laser. Its lower melting point however also means that you may run into problems drilling through extruded acrylic since the action of the rotating drill bit can create considerable heat.
  • Cast Acrylic - Cast acrylic is often the preferred choice if you plan on engraving the surface using a laser. This process, when carried out on cast acrylic, produces a dry white “frosted” finish that is quite beautiful. Cast acrylic is also the preferred choice if you need to drill tap holes into the surface due to the fact that, as we mentioned, cast acrylic has a higher melting point and won’t succumb to heat created by the spinning drill bit.

Working with Acrylic

There are many methods by which acrylic, and in particular acrylic sheets, can be worked to conform to your desired application.

Heat Bending

Heat bending is one of the most common ways of manipulating acrylic. Strip heaters are typically used to apply heat the acrylic in order to soften it up so that it can be bent at the desired angle. The strip heater is usually set to around 200° F so as to apply enough heat to soften the material without causing it to combust. There are several makeshift methods for bending acrylic sheets as well including toaster ovens (!) and heat guns although you’d do well to stick with the strip heater. To bend small pieces for custom applications the shaft of a soldering iron may suffice but again, this is a less than ideal solution and you need to be extremely careful not to apply too much heat.

Cutting

Without a doubt the most reliable and precise method for cutting acrylic sheets is the laser. However, it’s likely you won’t have access to a laser cutter and, if you’re working with only a few sheets of acrylic or the application does not require pinpoint accuracy there may be no way or no need to use a laser. In such cases where a laser is either not available or not necessary there are other methods you can employ to cut your acrylic sheets. A plastic scoring blade can be used as can traditional tools like a table saw or jigsaw. Just remember if you’re using a power tool to cut your acrylic sheet that you should use an acrylic specific blade.

Drilling

Drilling near the edge of an acrylic sheet is a sometimes dicey proposition, particularly if you are not using a drill bit designed for use with acrylics. Using the wrong bit or attempting to hurry the process could result in cracks or other damage to the area around the hole.

Polishing

If after cutting a piece of acrylic the edge has a frosty appearance to it you can flame polish it to restore its clarity. Flame polishing is a process best left to professionals as it can take quite some time to perfect your technique. Keep in mind though that if the edge in question will need to be glued later that polishing may undermine its ability to adhere effectively to another surface.

Gluing

In most cases acrylic is glued using solvent based adhesives. These adhesives typically soften the surface of the acrylic which allows it to chemically bond with the adjoining surface; rather like welding. Keep in mind though that this process may produce a joined area that is visually unappealing and that polycarbonate sheets may be a better choice if you need to glue things together.

Working with Polycarbonate

Like acrylic, polycarbonate has myriad applications in the modern world in everything from helmet visors to high tech display cases and more. Polycarbonate is created using a different process than acrylic and therefore has different properties. Most notably it is more malleable than acrylic while at the same time being more heat resistant. It’s also many times more shock resistant than acrylic resulting in it often being used for bullet-proofing.

Heat Bending

Heat bending polycarbonate is a trickier proposition than heat bending acrylic. This is due to polycarbonate’s higher melting temperature. While it’s not impossible to heat bend poly it is nonetheless not done as often as it is with acrylic. Things get even trickier if you attempt to bend your polycarbonate sheet using one of the DIY methods described above.

Cutting

Cutting polycarbonate requires a more deft touch than cutting acrylic. This is due to the fact that polycarbonate, while it’s more heat resistant, is nonetheless more pliable than acrylic. This malleability means that you need to exercise patience, especially at the start of the cut, to make sure things get off to a clean start. Hurrying will likely result in the blade becoming misplaced or the sheet being otherwise damaged.

Drilling

Drilling polycarbonate sheets is usually less troublesome than it can be with acrylic. Acrylic is brittle which means that drilling holes (especially near the sheet’s edge) may create cracks that radiate out from the drill location. Because polycarbonate is more pliable though cracking is rare.

Polishing

Polycarbonate sheets cannot be flame polished like their acrylic counterparts.

Gluing

Polycarbonate is not a good candidate for standard solvent based adhesives. Instead you should consider either using an epoxy glue or having the two pieces you want to join fused together. Bonding is the preferred method and is achieved by applying a small amount of methylene chloride along the edge of the polycarbonate sheet you want to fuse and then bringing the 2 sheets together. Make sure to carry out the bonding process in a well-ventilated area as the fumes can be toxic.

FAQs about Acrylic and Polycarbonate

Will They Yellow Over Time?

Acrylic will not yellow over time and even polycarbonate, which was once prone to yellowing, is now provided with UV stabilizers to prevent yellowing, even outdoors.

Are Acrylic and Polycarbonate Sheets Prone to Scratching?

Unfortunately both forms of plastic sheeting are more prone to scratching than glass. This may seem somewhat contradictory considering how impact resistant these materials are, but it’s the truth. So consider this before using either in an area where they’re likely to be scratched; such as high traffic areas or outdoors.

Are Acrylic and Polycarbonate Sheets Difficult To Clean?

No. Although you should be sure to use a soft microfibre or 100% cotton cloth to clean either (in order to prevent the aforementioned scratching). Polycarbonate is a bit more chemically robust and can tolerate ammonia although you should never use harsh solvents on either type of plastic.

Can Both be Used Around Food?

Both acrylic and polycarbonate can be used as a sneeze guard in a restaurant or cafeteria and acrylic is a common material for making food storage items. However there is some debate about whether or not polycarbonate is appropriate for storing food so until the issue is resolved you may want to stick with acrylic for food storage.

Are Acrylic and Polycarbonate Sheets Affordable?

Both are much cheaper than similar size glass panels. Also keep in mind that the risk of injury while working with plastic sheets is miniscule compared to working with large sheets of glass.

If you have any questions about measuring acrylic or polycarbonate sheets for a particular application give us a call on 01903 38902 or email us at: info@cutmyplastic.co.uk. We’re here to help.