Polishing The Edges Of Perspex Acrylic

In this weeks tech chat we’ll be describing and showing you a very basic Acrylic flame polishing demo using some very simple equipment. We don’t profess to be experts at this at all but we just wanted to show this quick technique for those who haven’t seen it before.

When the Acrylic is cut along its edge by a saw, it’s obviously going to leave those usual saw marks all along that edge. If these edges were polished without scraping, the saw marks would still be visible, so all you need to do is scrape along that edge to remove them.

We used the edge of a Stanley type blade (which we put protective tape where fingers go) but you can use anything similar, it doesn’t even have to be too sharp either. The objective is just to remove the saw marks and create a smooth surface before you start polishing, you could scrape the entire edge into a radius or put chamfers down each edge while your there if you like.  

Flame Polishing
Again we’re using a simple plumbers micro torch that runs on butane (lighter fuel) these mini torches are available from places such as Machine Mart or similar.

Hold the torch so the nozzle is around an inch from the Acrylic and at an angle so you can see the material easily as it melts as the torch passes over it. Now the trick here is to watch closely as you run the flame down the edge, travel too fast and the acrylic won’t have melted and created that polished edge. Too slowly and it will start to burn, you’ll know this has happened because you’ll here it crackling, all you need to do is blow it out, but the quicker you do this the less damage will be done and you may even get away with it, leave it too long and you may need the fire brigade.

Other tips
We suggest pealing the protective film back and away from that edge, if you don’t, it will just set on fire and stick to your Acrylic which isn’t great. It may also be a good idea to wear some decent gloves to protect your fingers from the scraper and also from the torch as the nozzle on those things gets very hot. Maybe a fire extinguisher would be a good idea just in case.

Don’t also be too keen to touch the acrylic edge until its well and truly cooled, for one it will still be soft and it will spoil, the other is you’ll get burned so leave plenty of time.