Tel me about engraving on a mirror

[Dave Johnson29]

Hi again people,

Sorry for all the questions. I always do a search first but I either came up with a zillion posts or none for this one.

In one post I read about putting an image on mirrored glass where the poster mentioned, "...the back clean up is easier."

The question is, front or back?

If it is on the front, is there a danger of reflection back to the lens etc? I thought I'd better ask first rather than shop for a new lens. :)

[Scott Shepherd]

I believe most people engrave on the back. No real risk there. Just engrave it and then you can smear paint on it or paint the entire backside.

There are people who have said you can engrave from the front and that they do it all the time, while there was someone who posted a photo of how the beam reflected back and etched their lid. So it seems some say it's okay from the front while others have said it's a no-no.

I'd always be concerned about shooting a laser being into anything highly reflective.

But the back side engraving does a really nice job once you color the back.

[Dave Johnson29]

But the back side engraving does a really nice job once you color the back.


Great, thanks Scott, I am back out to the garage to set it running.

[Darren Null]

The question is, front or back?
THE BACK!!!!

Turn air assist on if you have it- mirrors can really cack up your lens

[Dave Johnson29]

THE BACK!!!!


Calm Darren, say after me, "hhhhoooooooommmmmmmmmmmmmmmm" :)

I don't leap in until I have several responses from the people that I think know, but thanks for the loud tip! :)

[Peck Sidara]

Dave,

My thinking on mirrors; there are two types of mirrors, top reflective and bottom reflective. Top reflective are the type used in lasers to reflect the laser beam...Bottom reflective are the type that everyone uses on a daily basis.

I say you can engrave on most mirrors out there for two reasons 1) it's glass on top with a reflective coating underneath. 2) The wavelength of light a C02 laser produces are absorbed by glass before reaching the bottom reflective substrate.

IMHO, I don't think there's any problem with engraving on the top surface of *typical mirrors* for above reasons. I've done it plenty of times w/out any issues.

[Dave Johnson29]

The wavelength of light a C02 laser produces are absorbed by glass before reaching the bottom reflective substrate.


Thanks, I am only playing with it at the moment and have been using the back so far.

[Frank Corker]

Personally I wouldn't engrave on the front of the mirror, not because I can't or because I fear that the lens is going to zoom back up and fry my machine, but because it doesn't look very nice. Engraved from the back, the piece looks fantastic, the mirror remains a mirror and can be used as such with an image engraved on it. You just need to make sure that you get the correct positive/negative backgrounds or you will have something that has engraved well but just looks strange for some reason.

[Keith Outten]

I often put matt board behind mirrors that I engrave for color rather than painting. This way the customer can change colors any time they want simply by replacing the matt board behind the mirror.
.

[Dave Johnson29]

Engraved from the back, the piece looks fantastic, the mirror remains a mirror

Hi Frank,

We may have to stop meeting like this. :) Can you point me at a pic of one?

Yesterday all I got was a rastered square with no detail. Do you burn off all the backing material and "etch" the glass or is it a combo of backing material and glass?

From Keith's comments about the backing I am now a little confused. Something very easily done. <g>

[Darren Null]

Can you point me at a pic of one?
Here's one, lasered through the back and then painted black (on the back) to add contrast. You laser the backing off and it's see-through where you've lasered. So painting it black makes the picture stand out. All the bits you haven't lasered are, of course, still mirror.

An alternative to painting directly on the back of the mirror is to use a coloured board as Keith suggested...you can see the colour of the board through the glass where you've lasered the back off and if you get bored of the colour, just change the board.
http://lasering.x10hosting.com/etch/radar2_s.jpg

And this is one, unpainted and backlit:
http://lasering.x10hosting.com/etch/mirror--cristaleria.jpg

[Dave Johnson29]

Here's one, lasered through the back and then painted black (on the back) to add contrast.

Thanks Darren,

I am having a greater respect for this process. I cut a small portion of just the top of the father's head down to barely below the eyes on Frank's BMP and it took almost an hour to burn into scrap board. I will now sort out some Rates etc for the mirror backing.

That dog must have taken days! :)

Thanks again to all you guys. It is very much appreciated.

[Darren Null]

The dog was on the machine for about 12 hours. 100P 4S on my 10W. You could go a little quicker.

[Martin Boekers]

I've engraved the front, but as others have said the effect ain't all that great.

JDS has a product called black mirror that you front engrave and actually it's a nice product for it's price..

Now on regular mirrors even the ones JDS sells you can burn and burn all you want but you won't break through the copper coating. How do you tell if a mirror has this coating or one that be lasered?

On the guy who reflected a beam and it burned his cover, with how little depth of field there is I'm stumped on how he could be 8-10 inches away and still have the power to mark it (not that I would want it reflecting in my eyes though:cool:)


Marty