Acrylic or PMMA is a transparent thermoplastic and is technically classified as a type of glass called Acrylic glass. It is made from Methyl Methacrylate (MMA) and is also known as Plexiglas, Lucite, Acrylite and more.
It has properties like good tensile strength, UV tolerance, transparency, polishability and shatter-resistant. It is lightweight and can be used as an alternative to glass. When acrylic is cut it leaves rough edges which need finishing. The edges can be polished to make them appear shiny and smooth.
The different methods that can be used to polish acrylic sheets clear are sanding, flame polishing and machine buffing. You can follow any of the processes to smooth out the edges.
Polishing methods
Sanding
Take a 180-grit sandpaper and place it on the sanding block and cut it out to a larger size. Create a gap in the sanding block and push the extra sandpaper into it to tighten it. There should be no space between the sandpaper and the sanding block.
Take a spray bottle and spray lukewarm water on the acrylic piece. Every part of the piece should be sprayed with water. You can do wet sanding to make the piece shine. You should not sand the piece without using water as it can damage it.
Continuously rub the sandpaper on the piece to straighten out the edges and make them smooth. Use a higher grit sandpaper like 320-360 grit to get a greater shine. The water should be sprayed properly before sanding.
To give a lasting shine, repeat the process by using 600-grit sandpaper. By using a higher grit sandpaper you can make your acrylic piece shine more. You should not use dry sandpapers as there is a greater chance of heat generation.
Acrylic sheets clear
Flame polishing
For this, you will need a Propane torch and this process can be used to give an acrylic piece a glass-like finish. Move the torch to the edge of the acrylic piece and let it cool down until you can touch it. If you move the flame too slowly then the acrylic will melt and the material will be ruined.
Make 2-3 passes at one edge and remember to wait for the edge to cool down to get the perfect finish. Once you are done the acrylic will start to shine like glass.
Machine buffing
The acrylic piece should be cleaned and dried before starting the process. You can use polishing compounds that leave the surface clean and if you are not using such compounds then you will have to clean the sheet after polishing is done.
First, the acrylic sheet is buffed with a wheel which is charged with tallow. The edge is brought to a soft and smooth finish by using a soft buff without tallow.
