Quick crystal engraving question

[Patrick Licata]

Hello Creekers,
I know generally acrylic is lasered from the back and regular glass from the front, but how about crystal? Same as regular glass? Probably an obvious answer since they are both glass, but..........
Thanks, Patrick

[Gary Hair]

I almost always engrave anything clear on the back, glass and crystal get sandcarved instead of lasered.

Gary

[Martin Boekers]

Sometimes I engrave a logo on the front and text on the back, but
mostly It helps diffuse the light when engraved from the back.

[Jeff Belany]

JDS has a new product that is supposed to improve lasering on glass. They just sent out a video. They claim it gives a better 'frost' than without it. Hard to tell from the video. Most of the glass I do is round so not sure if it will even work as it needs to be tight to the glass.

Jeff in northern Wisconsin

[Martin Boekers]

JDS has a new product that is supposed to improve lasering on glass. They just sent out a video. They claim it gives a better 'frost' than without it. Hard to tell from the video. Most of the glass I do is round so not sure if it will even work as it needs to be tight to the glass.

Jeff in northern Wisconsin

Jeff, can you post the link? I must have missed getting that email.

Thanks!

[Jeff Belany]

Hope it's OK to post a link, You can also go to YouTube and search for Glass Laser Tape

http://www.youtube.com/watch?v=EDk31EcXgS4&feature=em-uploademail

Jeff in northern Wisconsin

[Dan Hintz]

$10 says I can recreate that here for 1/10th the price... ;)

[Martin Boekers]

I just ordered some to try it out. 6" x 36 yard was $36 I believe, $32 if you are AP.

$.30 a foot or so isn't too bad I guess, but yes Dan I'm sure with a bit of research
something simlar could be had for less.

I do a lot of Black Mirror from JDS Soap has worked well except when some letters "fracture"
slightly different, then there visibility comes and goes upon angle of view.

I am curious though as to protective coat on 2 sides as shown in the video.


Hmmmmmm you think they have the process patented? ( Stir it up, stir it up :) )

[nancy barry]

This appears to be a variation of the laser mask sold by Rayzist and several other places.. I sandblast all of my lasered glass and the mask works well to protect the non-lasered areas and is also easy for the laser to go through.. I am not sure that I agree that it is "more frosty" than glass with no tape/mask applied .. It is less splintery, I think.

[Martin Boekers]

This appears to be a variation of the laser mask sold by Rayzist and several other places.. I sandblast all of my lasered glass and the mask works well to protect the non-lasered areas and is also easy for the laser to go through.. I am not sure that I agree that it is "more frosty" than glass with no tape/mask applied .. It is less splintery, I think.

Nancy it looks like you tried this already, the stuff I ordered today will be here tomorrow. What settings did you start with?

many years back a company came out with a paper thin mint strip, (I think they are still out there) they were cool at the
time as it was like a transparent paper that melted in your mouth. I was thinking maybe this was similar as it would melt
(no not in your mouth but at laser temp.) and fill in the glass fractures. Don't know for sure just a guess. When it comes ini
f it has patent info I will look it up and see what the scoop is. As you say it may just be a re-packaged resist material.

[Gary Hair]

Martin,
I would be very interested to see how it works out for you.

Gary

[Richard Rumancik]

Patrick, if it is leaded crystal, the traditional answer is that you can't (shouldn't) laser engrave it at all. The lead will cause excessive fracturing and a crack can propogate right though the piece. But of course some people will tell you that they do it all the time . . .

True leaded crystal is very expensive and there are cheap glass items sold as "crystal" to make it sound expensive. Cheap glass can be laser engraved, but laser engrave true leaded crystal at your own risk. Sandcarving is less risky and looks better for an expensive item.

Here's a link you might find useful

http://www.engraversjournal.com/article.php/2360/index.html

[Dan Hintz]

Patrick, if it is leaded crystal, the traditional answer is that you can't (shouldn't) laser engrave it at all. The lead will cause excessive fracturing and a crack can propogate right though the piece. But of course some people will tell you that they do it all the time . . .

Patrick,

I'm one of those dissenters... I have done plenty of leaded glass, and I posted a pic or two years back of some ultra-thin Riedel glasses (if anything was going to break, THOSE were). These myths get published in "respected" magazines like Engraver's World and then become "fact", but my only guess is the person writing the article either made a mistake or they needed to "prove" they knew what they were talking about. The same myth is bandied about on how glass is engraved... some nonsense about impurities in the glass, etc. How glass does engrave is at the heart of why the breaking leaded glass thing is a myth... glass engraves due to stress fractures during cooling. You're only heating a minute portion of the glass, so when it cools, the crack will be limited to that area (10mils, give or take, typically less). It will not propogate through the unstressed portion of the glass.

Laser away! Start at a low power and build up, don't blast away at extreme powers and slow speeds as that's a sure-fire way to break something.

[Mike Null]

I agree with Dan, though I still prefer sandcarving glass/crystal. I also read what that particular author writes expecting that none of it is scientific and in actual practice only part of it will work. I am definitely not a fan of his.

[Dan Hintz]

Funny, I didn't even read the linked article, but I believe it's the one I was initially referring to. Through some good kizmet, I was able to obtain the first 20 years or so of Engraver's Journal for the cost of shipping. That article was in like the second mag I picked up from the pile (some science god is watching over me ;) ). Here's a quick quote form the article:

It’s the air and moisture that’s trapped within the glass that makes laser marking possible with a CO2 laser.
Let's examine the process involved in making glass... it's heated to the point of being molten. This is done in large warehouses where the average temp is probably quite uncomfortable to any but a plainsman. I can dry out my basement pretty well by running the heater long enough to get the room up to 80 degrees F. Let's see a raise of hands of people who think molten glass solidifies while trapping moisture that can later be re-vaporized with a tiny laser? Yeah, didn't think so. Sure, there are air bubbles trapped in cheap glass, but not in fine glass, and they both engrave the same (though I feel fine glass engraves more evenly).

As Mike said, the author didn't exactly approach the article form a scientific viewpoint, and the engineer in me gets a serious eye twitch when I read this stuff bandied about. If you're going to make a bold claim like "I know how this works", you had best be able to explain it properly.


Lasers have some real limitations. One is the type of glass that can be lasered. Any glass with metal in it is suspect. Although most colored glass will laser, there are times when so much metal has been added that it causes the laser to “skip” over an area of the glass. No matter how many times you laser it, those spots just will not mark.

Leaded crystal is hopeless. Leaded crystal has so much metal in it, trying to mark it with a laser is nearly hopeless. Don’t waste your time.
Ugh. The amount of metal in colored glass is pretty darn minute. A typical ratio is easily 10:1 or even less. Leaded crystal is 4:1, maybe more. He states "Leaded crystal is hopeless"... this tells me he has never even tried it. He made an assumption based upon his faulty theory, but he wants to be the authority in the room. Everything else from his mouth at that point should be taken with a giant salt lick. I'm willing to bet he doesn't understand why some colored glass can laser really well, and others show poor contrast.

[Bill Cunningham]

Leaded crystal etches just fine.. The only time I use the "lead expands in the glass" myth is when someone asks me if I can do a rather expensive piece of crystal, 'rush', that's probably going to require a ton of setup time. They don't want to spend a lot more money, and I really don't want to touch it because I have neither the time or inclination. So, I try to scare them out of it..:D