Is it safe to use the “paper towel” hack when cutting acrylic?

I came across this tutorial on how to cut acrylic in the laser without masking after reading about a glowforge fire due to loose masking after it cut. So someone recommended this video: How to get perfect acrylic cutting results by using wet paper towels - YouTube and someone else cited moisture concerns so I’m just wondering. The idea is to take 4 layers of damp, not wet paper towels and place them under the acrylic while cutting to create a bit of condensation to cool & reduce flashback.

If not, Is dawn soap safe to coat acrylic in the glowforge?

Thanks

Huh, that’s actually… a good idea?

I’ve often thought if we could just get something that absorbs all the excess laser energy without producing smoke it would be a good thing for lots of projects.

I’m not too psyched to get my steel honeycomb wet, seems like it might be a rust issue. Hmm. Maybe with a layer of aluminum foil underneath to protect the comb?

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Welcome to the forum.
I have moved your post out of Problems and Support as that section of the forum is for getting assistance for a machine that is not functioning as expected.

I believe the wet paper towel information has been discussed here in the forum. Also, I believe people have discussed using dish soap on glass and acrylic as a way to reduce cracks. I tried the wet paper towels one time with poor results.

I don’t believe that either of these tips are dangerous, but the fact is that acrylic has been involved in quite a few fires. Close supervision is required no matter what is being cut/engraved in the Glowforge. Loose masking on any material is a fire hazard.

Overall, I suggest you come to this forum for the bulk of your information regarding operating your Glowforge. The search function is very powerful in turning up lots of pertinent information.

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I did search originally and did not see any information, I was more wondering if it would be dangerous to use it in the machine due to humidity caused by a damp paper towel.

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Good idea on the foil too. I have seen people suggest just using the foil under acrylic while cutting to reduce flashback as well.

No issues, I do it all the time. :slight_smile:

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With towels or foil?

This is a very interesting idea. I am going to try is the next time I am cutting clear acrylic. Flashback is big problem for me and looks really bad on the clear acrylic.

Damp paper towels on foil. Seems like an awesome idea to me!

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I’ve used dawn dish soap on acrylic with good results. I didn’t have any flashback on cuts or hazing around my engraves. I only did it twice, though, before I decided that I prefer weeding masking to rinsing and drying.

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My problem is not that it is dirty and needs to be cleaned. My issue is that it flashes back up and melts the back of the acrylic.

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Coating acrylic in dish soap is an alternative to masking. You apply a layer of soap to the acrylic, run your cut/engrave, then wash off the soap. It’s not to wash off flashback damage, it’s to prevent it the same way paper masking does.

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Ah, interesting. I understand what you are saying now. But I mask my acrylic and the flashback still marks it up so it is not smooth.

I try to dial in the laser so that it just barely cuts all the way through. If it cuts the acrylic and not the masking on the back, I consider that a win.

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You should have a bit of leeway between cutting through the masking and having the reflected beam pierce back through the masking.

You could also elevate the acrylic (if the design allows for it) so that it’s physically separated from the crumbtray.

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This question is outside our team’s scope. I’ve moved it to the Beyond the Manual so the discussion can continue there.

Elevate the acrylic or just set a layer of sacrificial material underneath it. Could be cardboard, scrap acrylic cut-offs, thin plywood, etc to absorb the reflected energy.

Other laser manufacturers have aftermarket accessory beds that use thin metal pins to raise materials up and kill the flashback. They’re all expensive, but I’ve tried sourcing pins to make my own and the pins themselves are pretty expensive too.

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Orrrrr……

This particular one is a little thick to run on the Glowforge tray (0.375”), but you can find other depths/thicknesses:

These are basically ready-made acrylic crumbtrays.

Eventually they’ll get chewed up - so they are sacrificial, but they’re also pretty cheap.

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I use damp paper towels when cutting acrylics, and foil when cutting projects that have small parts I don’t want to have to chase through the crumb tray.

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