Can someone give me a quick rundown about engraving acrylic?

[Jacob John]

I've searched and found a few threads talking about it, but not really a quick reference guide. The reason I'm asking is that even with my laser exhaust and an additional portable exhaust, the smell is God-awful. My question is about that smell. I believe that I leave the exhaust running enough to vent all fumes, but I know there's some additional gassing (that can't be healthy).

However, even after several minutes, and even hours, the smell is still super strong. So, what I'd like to get is a quick guide for it, something along the lines of:

1. Following engraving, let sit in engraver for XXX minutes due to off gassing.
2. ???
3. ???

Do acrylic fumes leech onto the skin? I'm about to stop engraving it because the smell makes me nauseated. And again, I have 2 venting systems that pull a ton of clean air in/acrylic air out, but the residual smell is insane.

[Bill Reibelt]

First ensure that you have the correct acrylic, does the laser cut the samples cleanly that you have.
I have found that I cut or engrave acrylic at 35% speed and 80% power.
Check your piping and ensure that the exhaust line is only passing the air out side of the work area.
The inwards air line entrance point is well away from the exhaust.
If you air extraction is working correctly the smoke and smell is taken away from your machine and there is no smell in your work area.
Check any filter mesh areas of the air pumps to ensure that they are not blocked. Clean the fan areas to ensure full flow of the unit.

I have my extraction pipe about 3 foot above my shed roof to ensure that there is no flow back to my work area.
Hope this has been of some use to you.

[Gary Hair]

Is your exhaust blower inside or outside? Your blower and ducting will leak no matter how well you think they are sealed and you should have the blower outside at the very end of the ducting so you have negative pressure inside.

[Mike Null]

Acrylic continues to off-gas after cutting for some time. My blower removes most of the odor but the freshly cut pieces still carry the odor. You might try wiping the edges with dna if you're cutting cast acrylic. Don't do that if the acrylic is extruded as the dna will, almost instantly, cause it to craze.

[Chuck Phillips]

We cut 3mm acrylic several hours each day. There is very little odor in the shop. I would suspect the exhaust system or air assist needs improvement. We use a 2hp 230v blower (the larger Penn State one) and 6" rigid duct. 70 psi air assist. There is no visible smoke in the laser. All fumes exit the machine underneath the material.

[Dennis Watson]

I hope you dont have polycarbonite instead of acrylic. One more thing, dont do extruded acrylic. You only want to do cast acrylic.

[Ross Moshinsky]

I hope you dont have polycarbonite instead of acrylic. One more thing, dont do extruded acrylic. You only want to do cast acrylic.

Extruded acrylic cuts nicer than cast. It's just more fragile and temperamental.

[Doug Fisher]

Acrylic just smells during and after cutting. If it is paper protected, that will often add an additional real bad smell when cut by the laser. I have to set my just-cut acrylic pieces outside to air for a least a day.

After you cut, do you clean up all small cut drop pieces from the bottom of the laser? Do you wipe all smoke/tar off of the table and inside of the laser? If you have a honeycomb table, the downdraft will suck the smoke/tar down into the honeycomb cells. If you don't get in there and clean that black stuff off, you will always have that lingering smell. If you have a venting system that can't be closed off and air pressure enters from outside and blows through the tubing back into the laser machine, it is going to continue to spread that smell throughout your building.

[Kev Williams]

Is your exhaust blower inside or outside? Your blower and ducting will leak no matter how well you think they are sealed and you should have the blower outside at the very end of the ducting so you have negative pressure inside.
What he said, in spades :)

https://tyler.temple.edu/sites/tyler/files/architecture/Acrylic%20sheet.pdf <link to plexglas MSDS- pages 4 and 5 pertain to handling and toxicity...

[Bert Kemp]

Yikes Kev after reading that I'm going to seriously look at getting my blower outside.:eek:

[Dennis Watson]

He may not have enough air coming in to the room either. I know when I turn my exhaust blower on I have to open a door or window.

[David Somers]

Bert, It is a heck of a lot quieter too! Though not, perhaps, for your neighbors? <grin>

[Jacob John]

Yikes Kev after reading that I'm going to seriously look at getting my blower outside.:eek:

Yep, thanks for the tips everyone. I'm going to look at several of the suggestions here and use them. I have 2 venting systems right now.

Has anyone installed an in the wall vent? Since my shop is fully air conditioned, I could install it near the laser to help the existing one attached to the laser. The second system is just a giant smoke extractor with attached exhaust hose.