Tempered Mirror Glass

[Peter Meacham]

Has anyone had experience lasering tempered mirror glass - a customer is bringing a sample of such for a sample engraving. Not sure if the tempered part of this makes much difference unless it would react to the laser differently than ordinary mirror glass.

I have not done any mirror so I will have to experiment with settings - should not take too much power to remove (engrave) the backing of the mirror - but looking for any input from experience users.

I have a Trotec 25w machine.

Thanks, Pete

[Darren Null]

Shouldn't make any difference that the glass is tempered. Mirror backing thicknesses/layers vary, (even on the same bit of mirror sometimes, particularly old ones) so there's no definitive settings. As a general rule of thumb, ~about~ the same speed/power as you use to cut paper & thin card is a good place to start. Plus a little bit.

[Jack Harper]

I have done several large 5'x8' tempered glass murals with no problem. I do recommend the dish soap method when lasering any kind of glass though.

[Peter Meacham]

Jack

The dishwashing soap method being a light coat of soap on the glass I presume.

Pete

[Daniel Cline]

Hey Jack,

What process did you use to do the glass murals and do you have any pictures to share? I have some big glass pieces and would love to hear what worked for you.


Daniel

[Jack Harper]

Peter, Yes just a light coat will greatly improve your surface quality and prevent dangerous glass dust from entering the air. A real concern for us open bed laser guys.

Danial, I will have to take some photos and post them. I installed them in my conference room. The image was a vector art image form 123 photo service, it was a simple single tone image of tall grasses.

Separately, I learned recently that if you back fill your glass etchings with white tint like Van Sons printers ink, it really helps the image pop and further enhances the different gray levels, allowing for a deeper 3D appearance. Simple but it works.

[Peter Meacham]

Jack

Bear in mind that I am only doing the back of a mirror and removing the coating not actually engraving the glass itself (hopefully) - would you think that I still need to use the soap?

Pete

[Darren Null]

Might well be worth it. Removing the backing cacks up your machine bigtime.

[Jack Harper]

You would have to remove the back with many light passes to slowly get to the glass without actually etching the glass. Even doing this, it would be tough not to actually etch the glass. Mirrors have lots of issues starting with the fact that no two mirrors are the same. Materials used to coat the mirror change all the time along with the thickness. This also applies to a single mirror as the coating often varies in thickness. You will be all the way through on some spots while others still need more work.

[Daniel Cline]

The only way i have found is to simply go through and etch the glass as well. Like Jack said, no two mirrors seem the same but one thing is for sure to remove the backing you usally need lots of power.

Here are a one of mine...

[Peter Meacham]

Thanks everyone for your inputs

Another question - I cannot find how to change a bitmap to reverse image in Corel Draw - and back to a regular image - Can anyone advise pls.

Thanks, Pete

[Daniel Cline]

Hi Pete,

In the drop downs it's Effects,Transform and Invert

[Peter Meacham]

Thanks Daniel - right in front of me!!!!

[Bill Cunningham]

DON'T use dish soap on the back of a mirror.. the paint/coating on the back of most mirrors will come off if wet.. I learned this years ago, when my wife 'insisted' I put her bathroom mirror back up immediately after I wall papered.. After a few hours, the reflection was not flattering at all :eek: