Make acrylic glass: That's how it works

Among other things, acrylic glass is so popular because it can also be shaped and bent by do-it-yourselfers without too much effort. Nevertheless, there are some special features to be considered when forming acrylic glass, which we will explain in more detail below.

Acrylic glass - a thermoplastic and therefore malleable

The technical name of acrylic glass is "polymethylmethacrylate", in short also PMMA or colloquially Plexiglas. It belongs to the group of plastomers, also known as thermoplastics. These are engineering plastics that you can transform under the influence of heat. This process is not unique, but reproducible as often as desired. Of course, always provided that you use the right temperature range.

The bending, shaping and forming can be carried out differently:

  • freely bend by hand
  • bend into a specific shape using a female mold
  • using a stamp

Techniques for heating acrylic glass

Accordingly, there are also different options to choose how you can heat the acrylic glass. For the home improvement, however, the choice is already much lower due to the cost of such devices:

  • selective heating with a hot air blower
  • partial heating with a heat radiator
  • Heating the entire workpiece in a special plastic oven
  • Selective heating
  • The selective heating to form acrylic glass is the heaviest forming technique. This is mainly because the right temperature range of 150 to 170 degrees Celsius is very difficult to hit so precisely - especially if you have little or no experience with it. Therefore, it is always advisable to always practice on a test workpiece. If the heated part is not hot enough, the acrylic tears, it is too hot, it burns and becomes porous.

    To work better, there should be a special nozzle for the hot air gun, which focuses the heat once more to a smaller point. Nozzles that you also use for welding and gluing acrylic glass are well suited. Under no circumstances should you underestimate the difficulty of determining the exact heat range.

    Partial heating

    The partial heating, ie a larger portion of the acrylic glass, is much easier, but still has its pitfalls. At least you can make sure that the whole area is heated evenly. You can then quickly and easily shape the acrylic using a negative mold, such as a metal bar or a pot.

    Complete heating

    However, the shape at which you want to bend the PMMA should be warm enough so that the acrylic does not cool down too quickly. Here is a plastic oven most likely. If necessary, an ordinary oven (circulating air to heat the material really evenly) can also be used. You can then heat the negative mold with the same.

    Special features after the thermal forming of acrylic glass

    After molding, allow the acrylic to cool slowly to 80 degrees. At this temperature, you then have to hold it for a period of one to two hours. To cool down you should plan the same period again, as the subsequent, very slow cooling to avoid stress cracks must be taken into account. This working process is called annealing and is absolutely unavoidable to avoid stress cracks.

    Material-specific features of acrylic glass

    PMMA can already be distinguished by the last step in manufacturing. Thus, the production of acrylic glass is done either by casting or rolling (extrusion). The brand manufacturer Evonik Röhm GmbH (Plexiglas) identifies the acrylic glass either with "XT" for extruded or "GS" cast PMMA. Again and again it will happen to you that rolled acrylic glass is referred to as inferior to cast acrylic glass.

    Cast and extruded acrylic glass

    That's not right. In principle, these are two completely different products with independent properties. For example, the material properties of rolled acrylic glass are heterogeneous, but homogeneous in the case of cast PMMA. As a result, cast acrylic glass is much harder to reshape.

    But that's not all: with transparent acrylic, the bending area can become dull and translucent with non-transparent PMMA. If you paint colored acrylic glass, the color in the bending area may differ in clear nuances. Moreover, it retreats cast acrylic to its original orientation when heated again accordingly.

    Tips & Tricks

    In the house journal we offer you guides and instructions for many other processing techniques of acrylic glass. The casting of acrylic glass, the welding or the lasering of acrylic glass are just as interesting as forming and bending.

    Video Board: How to easily cut acrylic sheet