Decorating Lexan

I am wondering, what is the best way to decorate Lexan/polycarbonate? Would it be good to laser engrave it, or paint it, or just use a sharpie? Or is putting paper behind it the best way to go? Thanks

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If it were me, I would put paper behind it, but if you can laser engrave, then that’s awesome!

So we have a laser engraver but don’t know if it would look nice or be visible enough (since it would still be clear), we were wondering if anyone else has tried it before and if it worked well…

We have laser engraved black ABS plastic and it works fine and looks nice. I am not sure about clear lexan, but our mentor has laser engraved glass and the design came out white and looking fine.

Thanks! Also I am wondering, where do you buy the black ABS plastic? I haven’t looked at local stores yet but I don’t think Home Depot or Lowe’s has it…

We ordered our plastic from Robosource (

Wow that is a lot cheaper than I expected, thanks!

No problem.

Definitely use a laser engraver if it’s going to come out that nice!

I will be doing that! Thanks for the help!

Yeah I wouldn’t use paper if you want it to look nice. I used paper to decorate some lexan for my last comp and it was really wrinkly and just didin’t look good/professional in general. But maybe if you take quite a bit of time to make it look nice than it wouldn’t be too bad. I just didn’t, so…

You would just have to get it to lie flat.

We use a vinyl cutter and when necessary put paper behind the plexi. Wish we had a laser engraver… maybe next year.

Guys, be careful with polycarbonate (brand names Lexan or Makrolon) in laser cutters/engravers. Acrylic (brand name Plexiglass, illegal on VRC robots) works perfectly fine on laser cutters, but polycarbonate releases chlorine gas when cut, which in large enough quantities is toxic and corrodes components in the cutter. With proper ventilation it should be fine, but just make sure you know what you are putting into your machine, ensure that you are able and allowed to cut or engrave it, and take the necessary extra safety precautions.

I have fallen in love with decorating my polycarb. I prefer to make vinyl decals that I get printed from my local FASTSIGNS store. Here are some examples of their vinyl quality.

I have to second what @Kevin Boenisch says here. Despite looking a lot like acrylic, polycarbonate is a very different material.

Polycarbonate is made from BPA reacted with phosgene gas. It’s a beautiful, flexible, strong, non-shattering, and clear thermoplastic. However, if you heat it above its disassociation temperature, it can evolve phosgene gas. This is why the edges turn yellow when you cut it with a laser; that’s phosgene contaminating the cut.

Many people successfully mark and engrave polycarbonate. Here’s a link from one of the laser sites I use:

However, note that people successfully engraving this material are generally following specific instructions from their laser vendor or their plastics vendor. And they have good ventilation, and follow careful procedures. If the assist gas pressure, (generally low pressure air) exhaust pressure, (vacuum sufficient to clear the laser cabinet,) laser power, and laser speed are set correctly, it can work acceptably. If any of those things are wrong, you can seriously damage your health with this, and you can damage the laser optics as well. In extreme cases you can damage the bearings, guide rails, and other mechanical components inside the laser cabinet.

I’ve laser engraved polycarbonate under good conditions with acceptable results. It was very fidgety getting the power and speed set properly so that the engraving didn’t turn yellow-brown.

I’m not sure I’ll do it again, just because so much can go wrong. Note that symptoms of phosgene poisoning can take up to 48 hours to appear. And by then, you may have absorbed too much to recover. There is no antidote; they simply must remove it from your body before it causes you harm. Not worth it, in my opinion.

The maker space on E Michigan has a laser cutter/engraver and is set up with an enclosure that ventilates to the outside. That type setup is what you will want when cutting/engraving this type material.

I’m sure we can deal with the fumes.

for clear plexi laser engraving is difficult if not prepped right. Just depends on the brand of laser engraver. We use our vinyl cutter to make our graphic stickers for our robot.

Plexiglass (acrylic) is actually very easy to engrave compared to Lexan (polycarbonate.) Unfortunately, you’re not allowed to use acrylic on a competition VEX robot.

There is a difference in how extruded versus cast acrylic engraves. This photo tells the story pretty well:

Cast extruded laser engraved acrylic.jpg

The image is from this website: