Cut mirror acrylic

[Hannu Rinne]

I think this case is discussed here before but how should I cut mirror acrylic ? From the front side or from behind the sheet ? Should I mask the front side in both cases ? (I've never tried this before :o)

Regards,
Hannu

[Terry Swift]

Hannu,

I would tape where the laser will cut, especially on the front side; as not many may look at back; but if that's a consideration - do it to keep the smoke, etc. from collecting on it. Cutting face up would seem to be the thing to do; as the bottom can flash; but someone more experienced at it than me may have a better solution.

[Robert Alexander]

I always cut mirror acrylic from the back, and leave the protective paper on. I also put spacers under the acrylic to get it off the vector grid. It moves the smoke away from the acrylic faster. I don't like cutting from the front because of the beam possibly hitting the focusing lens.

[Hannu Rinne]

Thanks Terry,

Your answer was just what I was expecting, thank you :)

-Hannu

[Hannu Rinne]

Thanks Robert,

In my case there is a pvc film on the top of the sheet which I should replace with some other masking material...
I think I will test to cut from both sides of the sheet to see the results :D

Regards,
Hannu

[Joe Pelonio]

Replace the plastic film with paper transfer tape.

No one believed me but I once tried cutting face up with no mask to see what would happen and got engraved spots on the inside of my glass cover from the beam bouncing up.

[Rodne Gold]

Cut from the back , leave the protective film on the front. You need to use a LOT of air assist to eject all the melt when cutting cos if yoyu don't the melts seeps min between the front and the protective layer sliggtly , messes the front cut edge slightly. Try use cast mirror , you have more of a melt problem if you use extruded acrylic mirror.

[Terry Swift]

Cut from the back , leave the protective film on the front. You need to use a LOT of air assist to eject all the melt when cutting cos if yoyu don't the melts seeps min between the front and the protective layer sliggtly , messes the front cut edge slightly. Try use cast mirror , you have more of a melt problem if you use extruded acrylic mirror.

Rodne - why cut that way if your going to get melt on the face? If he is using a tape to cover the vector line he's cutting - then cutting from the front "should" pose no issue with bounceback. Then if it does melt - it will be on the back where it doesn't matter. I've got mirror acrylic to laser as well; but I'd be rastering as well; so I'd probably do it all from the back anyway; but for pure vector cut thru - why not the front if no bounceback.

[Rodne Gold]

I find it better to have the maximum energy density at the mirror surface (Focus on the back) as it has the cleanest cut of the mirror itself. The other way made the mirror flake a teeny bit.
We just got in a large shipment of cast mirror acrylic , very nice colours and thickness varying from 1.5mm to 3mm (1/16th to 1/8th) and did a lot of tests to see how best to cut it and that way worked best. This worked for the stuff we got.
IMO removing the original protection and retaping with transfer tape is a waste of time a great opportunity to introduce dust etc , the stuff is extremely static when you have stripped the covering , if the covering is plastic. Protection plastic is safe to laser cut..not PVC.
Your mileage may vary here , cos there is no real "standard" mirror acrylic and your machine might be better at cutting it some other way.

[Emma austin]

We cut a lot of mirrored acrylic (Designed mirror shapes).It just goes straight in the machine front side up, protective still on. We sell it like that, and leave the peeling to the customer, so we know it has no scratches on it.

[Gary Lyben]

What do you use to put the mirror on the wall? is there a double sided tape that doesn't harm the wall or mirror?

Thanks

Gary

[Hannu Rinne]

Thanks to all for the answers,

Here is some pictures of the first test. I did it using Rodney's suggestion. Not any bad melt or residue at all. Great stuff , but seems to be very sensitive to scratches. I used 3mm acrylic (I don't know if it's cast or extruded).

Regards,
Hannu

[Rodne Gold]

Just a tip : Be a little careful of using mirrored acrylic for exterior jobs, the mirror degrades quite a bit outside due to the coating applied over it not being suitable of outdoor use (check your mnfgr for this) , If we do mirror for outside we use a polyester vinyl applied over the back (laser friendly vinyl)
As to fixing it , use a THIN double sided tape , the normal thicker mirror tape thick stuff works , but the mirror tends to distort as it expands (acrylic expands quite markedly with heat , up to 1-2%)