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Gary and Jessica Houghton
01-17-2011, 4:38 PM
HELP!!!!

I have mirrored acrylic that needs to be cut into shapes. I masked the front and laid it onto my metal grid then cut from the back. There was FIRE! I stopped and cut through the masked front. Cut perfect.

My husband is worried that the paper mask will come off and will then be etching the top of the laser door or ruin the lens.

Can anyone tell me a surefire way?

I saw this thread, but it's years old now and wonder if it still applies. http://www.sawmillcreek.org/showthread.php?66435-Laser-cutting-acrylic-mirror

Thanks,
Jessica Houghton

Joe Pelonio
01-17-2011, 5:41 PM
I have cut a lot of it, with transfer tape on the front with no problems. If the film it comes with is clear plastic it can melt to the edges, so remove and replace with paper transfer tape as is used for applying vinyl lettering. I have also cut it from the back with transfer tape on both sides with good results, and have no idea why you were getting fire.

Mike Null
01-17-2011, 5:53 PM
I agree with Joe.

Gary and Jessica Houghton
01-17-2011, 6:06 PM
I have also cut it from the back with transfer tape on both sides with good results, and have no idea why you were getting fire.

Well, you just answered why I had fire...you masked the back as well. I didn't.

All I thought was, "FIRE, FIRE, FIRE! AAAAAHHHHH Put it out!"

Thanks for the reply. I will make another go.

Larry Bratton
01-17-2011, 6:08 PM
I cut it all the time from the face side. I don't recall exact reasoning but I but I researched it on here and found other people also cutting it with no reflection as feared. Works fine, just cut like regular acrylic.

Dan Hintz
01-17-2011, 6:37 PM
I cut it all the time from the face side. I don't recall exact reasoning but I but I researched it on here and found other people also cutting it with no reflection as feared. Works fine, just cut like regular acrylic.
The reason for no reflection from the front is pretty simple... any light that makes it down to the reflective layer (as thin as it is) must travel back up through acrylic. Since acrylic is opaque to the wavelength of the CO2 laser, any minor reflections will be dissipated back into the acrylic. Now, if the front surface was mirrored, things would get a little more interesting...

Lee DeRaud
01-17-2011, 6:54 PM
Well, you just answered why I had fire...you masked the back as well. I didn't.(scratches head) Why would that matter? If anything, I'd expect more flame with the transfer tape on the back (top). I've flame-polished several pieces of mirrored acrylic: if the coating if flammable, you couldn't prove it by me.

John Noell
01-18-2011, 12:23 AM
You're not cutting it without air are you? Peresonally, I never cut any acrylic without air assist on.

Larry Bratton
01-18-2011, 9:41 AM
The reason for no reflection from the front is pretty simple... any light that makes it down to the reflective layer (as thin as it is) must travel back up through acrylic. Since acrylic is opaque to the wavelength of the CO2 laser, any minor reflections will be dissipated back into the acrylic. Now, if the front surface was mirrored, things would get a little more interesting...

What he said :)

Gary and Jessica Houghton
01-18-2011, 9:56 AM
Thanks for all the replies. I will start cutting more this morning. Thanks again!

Mark Ross
01-21-2011, 9:31 AM
Yep, what John said. We cut acrylic mirror, 2 way acrylicmirror and clear acrylic sheets 10 hours a day 5 days a week. We don't do anything to it, we cut it just like it is when they ship it to us on 4X8 foot sheets. We cut it from the front and from the back and no issues. No way I would run it without air assist or without having someone close by. We all know about the hazards of fire and the need to stay by the machine.