Things NOT TO CUT

Unsafe Material for Laser Cutter

Material: Danger: Cause/Consequence:
PVC (Poly VinylChloride) /vinyl/pleather/artificial leather Emits pure chlorine gas when cut! Don’t ever cut this material as it will ruin the optics, cause the metal of the machine to corrode, and ruin the motion control system.
ABS Emits cyanide gas and tends to melt ABS does not cut well in a laser cutter. It tends to melt rather than vaporize, and has a higher chance of catching on fire and leaving behind melted gooey deposits on the vector cutting grid. It also does not engrave well (again, tends to melt).
Thick ( >1mm ) Polycarbonate/Lexan Cut very poorly, discolor,catch fire Polycarbonate is often found as flat, sheet material. The window of the laser cutter is made of Polycarbonate because polycarbonate strongly absorbs infrared radiation! This is the frequency of light the laser cutter uses to cut materials, so it is very ineffective at cutting polycarbonate. Polycarbonate is a poor choice for laser cutting.
HDPE/milk bottle plastic Catches fire and melts It melts. It gets gooey. Don’t use it.
PolyStyrene Foam Catches fire It catches fire, it melts, and only thin pieces cut. This is the #1 material that causes laser fires!!!
PolyPropylene Foam Catches fire Like PolyStyrene, it melts, catches fire, and the melted drops continue to burn and turn into rock-hard drips and pebbles.
Fiberglass Emits fumes It’s a mix of two materials that cant’ be cut. Glass (etch, no cut) and epoxy resin (fumes)
Coated Carbon Fiber Emits noxious fumes
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You’d probably be interested in #4:

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Also Stuff you shouldn't laser and various other places. This list feels like it’s been circulating since the fax machine era.

For what it’s worth, this laser cutter’s window is made of glass.

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Yes, tempered glass.

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Rectangular tempered glass.

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Perhaps they switched and we don’t know.

My glass lid is scratched to heck as I use it as a work surface to finish many projects.

The problem with all the posts like this is noobs stumble upon one of them and think it’s the definitive/official list. Would be nice if GF actually had one stickied or, better yet, in the official support pages.

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0.187 Thick Clear rectangular tempered glass.

I’ve got a few too for the same reason. It surprises me because I don’t use it as a cutting surface or any other abuse, just as a flat lay-out surface.

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I’m more disgusted by seeing the interior of some machines that look like they were spray painted tan! For God’s sake people, Clean your machines. that sticky residue on the inside can easily be cleaned with rubbing alcohol, or as I use, denatured alcohol. Cleaning also helps with the smell.

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Yeah, lasers are dirty by nature. I usually wipe down the rails, and the tube whenever I clean the inside lid. I have has occasion to remove the top left glass, and took the opportunity to vacuum out that area, just because I had that access. The two windows get cleaned about every fourth use, the lens and mirror when any film is visible.

I have to disagree with your statement that they can “easily” be cleaned. I mainly cut and engraved the PG draft board and that stuff is a sticky mess! I do regular maintenance but can’t keep up with the sticky layer. I tried once to clean a 1" square spot on my lid and it took a lot of elbow grease. I feel like I would have to wipe it down after every sheet to keep it clean. Am I alone or are there others with me?

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I think this is backwards. The laser cuts by applying heat (in the form of highly energetic photons) to the material that’s being cut. As a result, materials that strongly reflect the laser (or that do a good job conducting heat) will not cut well. Materials that strongly absorb the laser (or that do not do a good job conducting heat) tend to cut best.

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I work with a lot of PG draftboard as well and have found that isopropyl alcohol works well as a solvent for removing its gunk. I usually reach for the 91% because it evaporates faster, but standard 70% should work well too.

For the inside of the lid, specifically, I recommend the glass cleaner Sprayway (not Spray Away…Sprayway). It’s alcohol-based and comes in an aerosol can. The spray comes out as a foam, sort of like Pledge wood polish. Spray it on the inside of the lid, let it sit for about a minute (it drips slowly, but you can catch that with a paper towel) and wipe clean. Perfecto!

Honestly, Sprayway in general is just great as a glass cleaner. I’ll never buy Windex again. Way easier to apply and get off streak-free. Plus, it’s the secret ingredient to getting perfect smoothing on silicone caulk. If anyone’s interested in that, I’ll dig up the video.

…I just realized that this makes me sound like a Sprayway rep. I’m really not; any aerosol glass cleaner will likely do. I just know Sprayway is easy to find. Walmart sells a pretty big can for like $4.

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I’m with you. I mostly cut thick draftboard. I usually wipe the machine down at the end of each day. You wouldn’t know that from looking, a quick wipe down doesn’t take off this level of sticky gunk.

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I have a bottle of vinegar / purified water in a sprayer and blue shop towels,
The vinegar TAKES OFF that brown smokers lung sticky goo with one swipe

I burn all kinds of stuff, the worst criminal is paper craft for leaving residue,
but the last batch of baltic birch I got seems to be heavy with resin as well.

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I wonder where you got the stat about the #1 cause of laser fires being polystyrene foam. Anecdotally with the GF, it seems like acrylic is the main culprit. Specifically, the masking, but acrylic in general.

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Not sure the shape matters in this context… :stuck_out_tongue_winking_eye:

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I think @PrintToLaser got the joke… we were just going back and forth adding one more adjective.

I decided to stop before annoying everyone too much.

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My office makerspace (back when we had one) banned cardboard for being the #1 cause of laser fires.

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@RyanD, @InkTree, and @Macgeek, I haven’t found anything that cuts the smoke residue faster than household ammonia, full strength. 4-5 times faster than 91% alcohol, and much less elbow grease.
When faced with heavy stain, that’s your weapon. I cleaned this 3D engrave in about 30 seconds with ammonia and a toothbrush.

@InkTree, when I clean the light film from the inside I use a foaming glass cleaner too. For the inside lid, I spray a paper towel and wipe it. I’ll have to try that Sprayway.

A strong caution - be certain you don’t get any moisture on or even near that small PCB where the lid cable connects, respect the LED connections and the camera connection as well.

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Yarp, I do the on-the-towel approach for inside the unit as well. Great minds.

But daaang…full strength ammonia? Nothing like the ol’ litterbox smell inside, eh? :wink:

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