Acrylic is an awesome medium for C02 lasing. This article will cover the processing of acrylic for edge-lit projects but these principles still apply to basic acrylic etching in general. Before we jump in let’s cover a few important details.
There are 2 common variations of acrylic and while they are all chemically similar, they behave very differently from one another due to the manufacturing process:
- Extruded Acrylic: This is what is commonly found in big box and local hardware stores. This is made by forcing the acrylic resin through a form. This type is usually masked in plastic and when etched produces very little contrast.
- Cast Acrylic: This type of acrylic is not commonly found locally but it is used in aquariums so a pet or aquatics store may be worth a try. It is produced by pouring the resin in a cast and subjecting it to heat and pressure. Cast is usually masked with thin craft paper but not always. Cast is great for etching and produces remarkable contrast.
You can learn more about the differences between cast and extruded HERE.
It is called edge lit because light enters one or more edges of the substrate by using ambient light or a light source such as an led array. Once the light is inside the material, it travels throughout the entire volume of the material.
The acrylic-to-air boundary surfaces create internal reflectivity that keeps much of the light inside the material ( like when you are under water and the surface looks mirrored from below) and it is diffused over a wide area. Etching the acrylic allows the light to escape at the ablated areas and causes the engraved area to glow.
When engraving you usually only want enough power to sustain a uniform beam signature and to barely ablate the substrate however variable depth engraving (3D relief) can produce some interesting and desirable effects.
When you cut acrylic there are a lot of factors at play besides your speed, power, focus, etc… Russ Sadler has some great in-depth tutorials on one of his YouTube channels HERE.