Let’s get started. The first thing you’ll need to do is cut the plexi to the size you want, but make it 2mm bigger on all sides, so that you can sand out any imperfections. You can do this with a jigsaw. It's pretty straight forward. Measure up the lines and let your jigsaw do the rest.

I used a piece of transparent red plexi i had lying around:

I cut a piece off:

You might end up with less than straight edges like mine above. That's no problem. That's why we leave 2mm on the edges.

Now we need to get all our sandpaper:

Now you start with the REALLY rough stuff first – the 36grit. This sand paper is really rough, so you’ll shred through a millimeter in a minute. Use this phase to get the edge of your plexi absolutely straight. I use a big sanding "block" for this. Doing it by hand will not give you perfectly straight edges, you must use a block of some sort. Once you've done the sanding with the 36 grit sand paper, your plexi will look like this:

After the 36, your plexi will be incredibly rough. At least now it’s at about the size you want. The rest of the sanding from here on is repair and polish work. After the 36, you can sand with the 80 grit paper. The 80 is much smoother than the 36, but it’s still way too rough.  Once you've sanded with 80, your plexi will look something like this:

Now we sand with 400 grit sandpaper:

We’re almost done sanding. Start sanding with the 1200. Remember that the 1200 and the 2000 will be WET sanding, not dry. Once you’re done, you’ll see that the plexi is VERY smooth. 1200 does wonders. If you want, you can sand with 2000 as well. I do, because I feel it just adds that extra bit of smoothness:

Okay, the plexi is ready for polishing! Here's what i use for the polishing:

This will add a glassy effect to the edge of the Perspex. I just use a household brass polish. Rub the polish onto the edge of the Perspex using a cloth. This only takes a few seconds. Once that’s done, rub that same edge with a soft dust cloth. Make sure you rub nice and hard. Your result should look as smooth as a sheet of glass:

Not even a laser cutter can do it like that!

Should you need any help, or have any suggestions, please feel free to drop me an email.

Good Luck and happy modding!

- Ettienne