Picture of How to Flame Polish Plastic
Have you ever used plastic sheet in a project before? It looks really cool, but it can be a pain to make look perfect. This guide will show the basics of polishing plastic using fire. It will create a polished edge that will catch the light in a very brilliant way. All of the tools used in this guide are available at TechShop.

What you will need:

Plastic (I used acrylic) Special Note : Do NOT try to flame polish polycarbonate, it will bubble and will be ruined
An orbital Sander
At least 100 grit sandpaper, I reccomend going up 300
a propane torch (this can be picked up at your local hardware store)
some form of tape that can be used for masking.

Step 1: Preparing your plastic

Picture of Preparing your plastic
This scrap piece of plastic has no protective film on it. It is important to keep your plastic protected as often as possible to avoid scratches. I used blue painters tape to re-mask the unprotected areas to avoid scratching in the future steps

There is a youtube video that says that a propane torch doesn't get hot enough and you need a MAPP gas torch. Maybe that's why his results were less than optimal.

dwyates3 years ago
Although I haven't seen optimal results from torch polishing, I'd have to agree with pfred2. The best results come from the best tool for the job in skilled hands - your end results (as seen in the pics) do show scratches. You'll (likely) never get better results than using buffing wheels & compound - plus, far fewer ruined material. Yes, fire can be fun, but in this case there's a better way.
Having said that, if a torch is all you have... fire it up!
code_neon (author)  dwyates3 years ago
Meh, my piece I was polishing was some scrap that was only sanded to a 120grit. Had this been a piece of plastic I cared about I would have sanded it to at least 320grit and then flame polished. That makes it look plenty slick
I am confused as to why you didn't show or detail this in your instructable, may people just look at pictures would see your end result and think that's not giving a great finish. You may not care about the plastic but you could care about the instructable.
pfred23 years ago
Torch polishing works but actually polishing achieves optical accuracy. Which is to say it just comes out better. So put down the torch and just grab some polishing compound and do it. It is a bit more work, but the results are worth it.
code_neon (author)  pfred23 years ago
I disagree, the best result come from what tool the user is best skilled with. Plus, fire is way more fun!
Your opinion varies from professionally qualified ones. I think I'll side with the pros. In fact I know I am. Flame finishing plastic is a neat trick, but mechanically inferior to polishing. Whether you agree or not is irrelevant.
code_neon (author)  pfred23 years ago
I feel like you are not grasping the point of this instructable, which is not about what type of polishing technique is better, but is only about how to flame polish plastic

Continuing in the direction of this conversation, I am not sure why you would have to side with a pro on about how to have more fun, but as someone who has worked and continues to work professionally with plastics, I can tell you that fire is indeed the more fun process :)

In addition, the best result will always come from the tool a person is best with.