Lasering Mirror

[Ray McAlister]

Is it possible to cover the front of the mirror with masking tape and laser the front side. I kinda expect that the laser would cut though the tape, hit the mirror and reflect back causing some catastrophic damages.
And I'm not brave enough to try it........:eek:

Thanks
Ray

[Carol VanArnam]

I think since you thought of it you need to try it. Take pictures and let us know how it comes out.... Wait and do it on the 4th of July so if it goes BANG you can tell everyone you planned it that way......

now I want to know if it works or not.... hmmm

BE BRAVE TRY IT..... (I'll hide and watch)

[Scott Shepherd]

I wouldn't recommend it. There's a thread here where someone says they have done it no problem and on the same thread, someone said it reflected back and damaged the cover.

From my knowledge of larger lasers in the metal world, one thing in the early days that gave lasers a fit was aluminum. When aluminum goes molten, it's very reflective and would reflect back through the lens and damage the laser.

At that time, a reflection back was a bad thing. I have no idea if things have changed, but I wouldn't try it with my laser.

[James Stokes]

I have lasered lots of mirrors, never had a problem yet. Laser away.

[Gary Hair]

Sandcarving takes away any possibility of damage...

Gary

[Frank Corker]

The biggest let down when engraving the front is the double image. Ruins the effect (personal opinion)

[Brian Robison]

I agree with both James and Frank.
I've done it but it's not real attractive IMHO.

[Darryl Hazen]

We've done several mirrrors by reversing the image and lasering through the coating on the back of the mirror. Then painting over the engraving area with any contrasting color paint to make it more visible from the front.

[Jason Lippert]

We also do a lot of mirrors. We mostly use the front side for text, or design elements. I also recommend the dish soap trick if you are lasering the front.
Also, one thing I never understood about the whole concept of ruining your optics with mirror. If the laser is reflecting back up to the lens to damage it. How is it focused enough at that distance to do anything bad? Throw your laser 1/2 inch out of focus and you can barely laser plastic. Much less fry optics. JMO:D

[Mark Winlund]

We also do a lot of mirrors. We mostly use the front side for text, or design elements. I also recommend the dish soap trick if you are lasering the front.
Also, one thing I never understood about the whole concept of ruining your optics with mirror. If the laser is reflecting back up to the lens to damage it. How is it focused enough at that distance to do anything bad? Throw your laser 1/2 inch out of focus and you can barely laser plastic. Much less fry optics. JMO:D

I agree. Has anyone ever damaged their optics with mirror or aluminum material with an engraving type laser? I have done a lot of mirror acrylic and never had a problem. I think this tale has sprung from industrial lasers (1000 watts and up) where just a little reflectance will put a lot of power into the mirrors and lenses. My machine puts out a measured 140 watts and is still using the original optics.

Mark

[Roy Brewer]

Is it possible to cover the front of the mirror with masking tape and laser the front side. Ray,

The real question is "can I engrave glass?"
The wavelength of a CO2 laser is such that the surface of the glass completely absorbs the energy. Nothing but a bit of Ultraviolet light gets through to the back side of the mirror. That's why your technical support manual tells you that if you are ever working on your system with interlocks defeated (possibly for alignment purposes) anyone/everyone in the room should be wearing glasses; for CO2, no special glasses, because glasses (including plastic lens) absorbs the last possible damaging effect of the CO2 laser beam.

The masking tape question was incidental, probably, but there would be no purpose for it as far as I'm concerned (soapy wet, unprinted newspaper, would make the edge quality better and increase the opacity).

I agree with others, it is hard to get anything esthetically pleasing on the front side of a mirror because of the "double imaging" that Frank mentioned.

That which might have possible negative effects is material that does not absorb the laser beam; most noticeably, metal. The major manufacturers of laser tubes now have filters built in to minimize the potential damage if a CO2 laser beam were aligned so well that it could get all the way back to the tube.

Scott mentioned someone damaging the Lexan lid(cover) of their laser. I have seen this at least twice on two different brands of lasers, but in both cases they were 120 watt systems. At that wattage, you still have enough energy focused to damage the Lexan if reflected off a shiny metal surface. The damage, while very visible, was minor, but enough for someone to get a great deal on the demo used at the trade show.

[Ray McAlister]

Thanks for all the replys! It is acrylic mirror, and i want to laser the front just enough to cut the plastic protective film to peel back. With the colored acrylic we've found if you laser the plastic film and remove to glue another piece on top that the coating will protect the acrlic from being damaged from the glue. (I hope this makes sense, it's late and i'm tired)

Thanks for all the info posted on this board, truely the best information about lasers, and i've found myself lurking in the turners forum and thinking about a small lathe........
Ray

[Frank Corker]

Has anyone ever damaged their optics with mirror or aluminum material with an engraving type laser?

Mark

I once (very early on) put a small aluminium dish in the laser, the type you get cupcakes in, I wanted to see if it would make any mark whatsoever. Seeing as it didn't make any difference when I had done a mirror I didn't see the harm. Anyway, the little dish had a slight indentation, the beam hit that bounced up and burned a permanent squiggly pattern on the safety acrylic door glass and it's still visible now! That was the last time I did that. So you do have to be a little careful.