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View Full Version : If I ever take on glass engraving again, smack me...



Scott Shepherd
09-19-2010, 7:27 PM
About this time last year, did a glass engraving job. Something we don't do, awards. It was a pain in the butt then. Small text, letters not appearing, then magically appearing (if you have engraved glass, you know what I'm talking about), all the "fun" things that go along with glass engraving. Really fought that job back then.

A call came in about a month ago, people wanted to do the same thing. Great, I have all the settings (still in my job control software), I have all the fixtures. Okay, we'll do it.

Ordered the glass. First delivery date of the glass to us. Missed. Called, sorry, it's going out in a few days. Missed that. Called again. Got new date. Missed that. Finally got a tracking number, stuff is due in Thursday afternoon. Comes in, great, we have a whopping 1 day to get it done unless we do it on the weekend. Thanks for that. No ability to screw something up and get some more in, only a couple of extras. Great, thanks for that too. Nothing like the pressure of having no way to replace the items and figuring it all out at the same time.

Engrave the first one. Not even close to working. After 2 hours of working on the same sample, trying to get a good, clean mark on small letters, I went home, way past quitting time. Great, I'll pick it up in the morning with fresh thoughts.

Wrong. 3 hours later, I finally get the magical combination of settings and technique figure out. It's now 10 hours later (or something like that) and I'm still working on the stupid things.

If I EVER think about taking a glass job to engrave, someone, please, do me the favor and smack the back of my head and ask "what are you thinking?".

Have I mentioned I hate glass?

I hate glass.

(where is that brochure for that sand carving setup????????)

Martin Boekers
09-19-2010, 7:43 PM
I feel your pain! I still do glass, but it's a pain.

I have a couple of clients that love a certain award
what the bigger problem with this award (it comes
from a very good vendor) but the faux wood spray
on the base is usually bubbled or chipped.

This is the ONLY product I have removed from my
inventory becuase of it's consistant poor quality.

I guess I'm not the only one with the ("magic disappearing letters)
I do stick to block fonts on glass and look at it carefully while
positioned on the table and run it a second pass any more than
that the piece is trashed.

With the profileration of lasers you think someone would have
come up with a glass formula that is consistant for our application..

I do alot of those crystal globes that Marco sells, I guess these are hand finished because the bases
are rarely square so you waste time testing to get everything centered
as possible. It takes more time to square evrything also as I haven't
been able to find a clamp and leveling system that was reasonably priced.

So I do feel your pain!:(

Marty

Gary Hair
09-19-2010, 8:05 PM
In a word - sandblast!

There are some people who swear by lasering glass, I'm not one of them. I started sandblasting 3 years ago and haven't looked back. I have done glasses by the hundreds and stone from marble-size up to a 2300lb slab. Get into sandblasting, you'll never look at glass and stone the same way again!

Gary

Robert Walters
09-19-2010, 9:41 PM
If I EVER think about taking a glass job to engrave, someone, please, do me the favor and smack the back of my head

And your preference would be...

Option A:
http://www.dadsclub.com.au/wp-content/uploads/2009/10/smack.jpg



Option B:
http://4.bp.blogspot.com/_B1HzWSIFSbg/S2Pks9m_t-I/AAAAAAAADyc/FutKp7SWu70/s320/smack3.jpg

Ed Lang
09-19-2010, 10:15 PM
Option "B" for him!

Frank Corker
09-20-2010, 4:36 AM
No really Steve, option C will do you just fine!

Chuck Stone
09-20-2010, 7:48 AM
ok, now that I read about the missing letters, I'm curious.
I hadn't read it anywhere before, and I thought I was going crazy.
(still a possibility, I know)

I did the same piece three times, and it was always fine on screen, but
that same letter refused to show up on the glass. I never knew why.
What causes this?

Scott Shepherd
09-20-2010, 8:11 AM
Chuck, it has to do with that section of glass not fracturing like the other areas. You can take something sharp, a pick or something, and touch it and some times it will pop and instantly appear. Like you have released that surface tension that's holding it back.

I'll take option B or Frank's option. Either one is fine. 12 hours on that project yesterday. I think I might have made $2 per hour once the smoke clears :)

paul mott
09-20-2010, 8:16 AM
For me sand blasting is definitely the best, it leaves an open surface which looks a bit like a mountain range of peaks and valleys. Laser etching, on the other hand can boil the glass and create a semi closed-cell structure which looks like a series of minute spheres, some broken, some not.
It is curious but some of the laser etched glass items that I have done seem to be hygroscopic, they can change their contrast ratio with changes in humidity - really weird.

Paul.

Dan Hintz
09-20-2010, 8:56 AM
Steve,

I'll gladly take your glass jobs... done quite a few and never had a problem :)

Scott Shepherd
09-20-2010, 9:18 AM
Great Dan, I'll bring you the file and some samples and if you want it next time around, you can have it.

I'm done with it. Never again.

I just glued my last piece of glass to it's base, the UV light is curing it now, then it's off to the customer.

Dan Hintz
09-20-2010, 9:21 AM
I'll have to borrow that UV curer, though :)

Dan Ashlin
09-20-2010, 9:56 AM
The first order we got at my new shop for glass, someone brought in some of those stemless wine glasses from target. They are horrible for the disappearing text. Went through the whole job and it looked like maybe 3 or 4 letters showed up. Opened the hood and it sounded like the glass broke. Looked down, there's all my engraving. Scared the hell out of me.

TONG LI
09-20-2010, 12:54 PM
Just curious, what's the speed and power do you use and are you doing vector or raster?

I never had any problem with glass. Well, I lied, we blew up a beer in the laser machine at a convention while vector cut our logo with too high a power setting, lol.

Tong

Dan Hintz
09-20-2010, 1:27 PM
we blew up a beer in the laser machine at a convention while vector cut our logo with too high a power setting
Ouch! Not only a party foul, but a machine cleanup and embarrassment factor, to boot...


EDIT: I find the timing of this thread somewhat amusing considering I'm currently working on my book's chapter on glass processing...

Robert Walters
09-20-2010, 1:36 PM
Opened the hood and it sounded like the glass broke. Looked down, there's all my engraving.

That sounds like thermal shock (and makes sense).

The glass is hot from being lasered, and the cooler ambient air hits it when you opened the lid and BAM, shatters at it's weakest points (where if was lasered).

I wonder if that's actually a "solution" to disappearing characters?
Give them a thermal shock using air or even a can of air (upside down?).

If it's a glass, I wonder if inserting ceramic wool during lasering would make a difference?

Is it possible that you could have been lasering BELOW the surface of the glass?
Microfracturing the sub structure, so there is a solid thin layer at the surface where the laser is going through, but not being effective, and the letters you do see are when the glass is still hot, and then "fuse" back together as it cools.

Maybe not focused correctly, maybe power setting too high/low.
I wonder if the surface of glass has been "hardened" (tempered) to help prevent simple chips in normal usage.

Dan Hintz
09-20-2010, 2:11 PM
Robert,

You have to be going pretty darn slow to really heat up glass in the typical machines seen here (though I've done it in a failed attempt to etch the back of a glass tile). At the CO2 wavelength, the beam only makes it about 0.5mils into beyond the surface before being fully absorbed.

Mike Null
09-20-2010, 4:31 PM
Put another way, you almost have to be trying to crack the glass to make it happen.

I've engraved a lot of tempered glass with zero problems.

But, if you engrave enough glass, you will have those missed spots Steve mentioned. Usually re-running the piece will solve the problem.

All things considered I'd rather sand blast or use my diamond burnisher on glass.

Robert Walters
09-20-2010, 6:19 PM
Robert,

You have to be going pretty darn slow to really heat up glass in the typical machines seen here (though I've done it in a failed attempt to etch the back of a glass tile). At the CO2 wavelength, the beam only makes it about 0.5mils into beyond the surface before being fully absorbed.

I have no idea. Just sounded good in theory =)

If it's these "cheap" mass produced glassware, who know what the chemistry make up may be to make them cheaper to produce.

Kinda like that home brewed cermarc someone came up with using plaster of paris. Mineral chemistry is kinda voodoo to me, but damn cool imo =)

I know the laser is micro-shattering, but what glass makeup/process produces the best results I don't have the foggiest idea.

Chuck Stone
09-20-2010, 6:23 PM
EDIT: I find the timing of this thread somewhat amusing considering I'm currently working on my book's chapter on glass processing...

Don't mis-spell our names in the credits.. :p

Martin Boekers
09-20-2010, 6:55 PM
The first order we got at my new shop for glass, someone brought in some of those stemless wine glasses from target. They are horrible for the disappearing text. Went through the whole job and it looked like maybe 3 or 4 letters showed up. Opened the hood and it sounded like the glass broke. Looked down, there's all my engraving. Scared the hell out of me.

Another issue is stemware with a slighty crooked stem, it's usually not
a lot but just enough.

I do a fair amount of black mirror from JDS, nice product, but yes, sometimes
the letters dissapear. I believe it's because when the glass fractured it
did it at such an angle the light reflects off it differently. It is engraved
and by tilting it slightly the letters are visible.

Dan Hintz
09-20-2010, 7:45 PM
I know the laser is micro-shattering, but what glass makeup/process produces the best results I don't have the foggiest idea.
Let me put it this way... the (annoyingly persistent) idea that glass etches because it contains impurities, water vapor, and a myriad of other junk that the laser boils or heats to explosion is completely false. Whomever started that idea rolling probably guessed that's what was happening (and it's a reasonable guess if you choose not to pay attention to the science behind it), and ever since then I have seen it propagated not only in online forums but in print many times over (even in mags like A&E, Sign and Digital Graphics, etc.). Now it has become like one of those internet rumors that just won't die, an internet wive's tale.

I proved that notion false the moment I started placing high-quality glass, high-end optics, etc. into my machine and pulled out great, consistent etchings with zero chipping. I've even proven the whole "leaded glass is verboten" theory false. Details of what is truly happening will be in the book, and hopefully understanding what's really happening will help others create better engravings.

I know I've said it before but I'll say it again... if people can truly understand why the laser does what it does on every substrate, they'll be able to make logical leaps to new substrates that previously would have been unlikely.

Kathy Madan
09-20-2010, 7:55 PM
Put another way, you almost have to be trying to crack the glass to make it happen.

I've engraved a lot of tempered glass with zero problems.

But, if you engrave enough glass, you will have those missed spots Steve mentioned. Usually re-running the piece will solve the problem.

All things considered I'd rather sand blast or use my diamond burnisher on glass.

I have never mastered the laser glass engraving thing either. We do almost all with the diamond burnisher. Even then we will find "hard spots" in the glass that the diamond simply will not cut thru on a single pass, sometimes in several passes. It is a total frustration to have perfectly clear engraving with just one missing letter. Sometimes I take my hand engraver to it, just to finish it off.

paul mott
09-21-2010, 2:29 AM
Let me put it this way... the (annoyingly persistent) idea that glass etches because it contains impurities, water vapor, and a myriad of other junk that the laser boils or heats to explosion is completely false. Whomever started that idea rolling probably guessed that's what was happening (and it's a reasonable guess if you choose not to pay attention to the science behind it), and ever since then I have seen it propagated not only in online forums but in print many times over (even in mags like A&E, Sign and Digital Graphics, etc.). Now it has become like one of those internet rumors that just won't die, an internet wive's tale.

Dan,

When I look at some laser etched glass under the microscope I see hollow spheres, some broken some not. If they are not bubbles then what are they and how do you think are they formed ?.

Paul.

Dan Hintz
09-21-2010, 7:08 AM
Paul,

I'll save the detail for the book (otherwise I'd be constantly cutting and pasting), but glass "etching" comes from localized surface tension. The laser heats up the surface of the glass to the melting (flow) point, and as the glass rehardens, the surface tension increases drastically in a localized fashion. Eventually the pressure is too much and the surface fractures, leading to the pits you're seeing under the microscope.

As I mentioned earlier, this is a surface phenomenon as the CO2 wavelength is absorbed completely within less than 0.5 mils (<0.0005") of the surface.

paul mott
09-21-2010, 7:13 AM
Thanks Dan, I will have to study this some more.

Paul.

Joe De Medeiros
09-21-2010, 8:32 AM
Paul,

I'll save the detail for the book (otherwise I'd be constantly cutting and pasting), but glass "etching" comes from localized surface tension. The laser heats up the surface of the glass to the melting (flow) point, and as the glass rehardens, the surface tension increases drastically in a localized fashion. Eventually the pressure is too much and the surface fractures, leading to the pits you're seeing under the microscope.

As I mentioned earlier, this is a surface phenomenon as the CO2 wavelength is absorbed completely within less than 0.5 mils (<0.0005") of the surface.

here's a quote from wiki.


But when a laser hits glass or stone, something else interesting happens: it fractures. Pores (http://en.wikipedia.org/wiki/Porosity) in the surface expose natural grains (http://en.wikipedia.org/wiki/Grain) and crystalline "stubs" which, when heated very quickly, can separate a microscopic sized "chip" from the surface because the hot piece is expanding relative to its surroundings. So lasers are indeed used to engrave on glass, and if the power, speed and focus are just right, excellent results can be achieved. One should avoid large "fill" areas in glass engraving because the results across an expanse tend to be uneven; the glass ablation simply cannot be depended on for visual consistency, which may be a disadvantage or an advantage depending on the circumstances and the desired effect.Some other info:
different glass formulas have different COE (coefficient of expansion) that's why some will mark better than others, Pyrex type glass has a COE of 32, where as typical window glass is around 82, Fusing glass comes in a few COE's 90, 96 are the most common, then there's the 104 used most to make lampworked beads, also very susceptible to thermal shock. The lower the COE the harder it is to mark, tempered glass does not alter the COE, it just aligns the structure to make it tougher. This all goes back to what Dan said about the surface tension, the higher the COE, the better chance you have of fracturing the surface, due to localized thermal shock. I have been working with glass fusion & lampworking for 11 years, as part of my art, and work with glass from 32 to 104 COE, I have also written a few pages on this for a science text book, on how art relates to science.

Dan Hintz
09-21-2010, 8:37 AM
Joe,

Did you actually just quote a Wiki article as reliable info? :(

paul mott
09-21-2010, 9:02 AM
I wonder if all Wiki articles are incorrect / inaccurate of just the ones that we don't actually agree with :)

(I once worked for a guy who said that all newspapers were politically biased so every day he bought two politically different newspapers, read both, believed what he wanted to believe from each and then thought he had the truth).

Paul.

Belinda Williamson
09-21-2010, 9:11 AM
If I EVER think about taking a glass job to engrave, someone, please, do me the favor and smack the back of my head and ask "what are you thinking?".

Have I mentioned I hate glass?

I hate glass.

(where is that brochure for that sand carving setup????????)

OOOOH, pick me, Steve, pick me! I have the smack to head down pat, mainly because I smack myself so often for taking on jobs I should have refused.:rolleyes: I have a glass job coming up in the next week or so for a wedding planner friend of mine.

Joe De Medeiros
09-21-2010, 9:12 AM
Joe,

Did you actually just quote a Wiki article as reliable info? :(

no just for comparison, reread my edits i added after

Dan Hintz
09-21-2010, 9:44 AM
Ah, the edit makes a lot more sense. It's a shame you're not closer as it sounds like a beer or two shared over the smelting pit would turn up some interesting conversations... I love peering into the science of what's going on rather than taking it as rote (unless it sounds "good enough" to not worry about).

Scott Shepherd
09-21-2010, 9:57 AM
OOOOH, pick me, Steve, pick me! I have the smack to head down pat, mainly because I smack myself so often for taking on jobs I should have refused.:rolleyes: I have a glass job coming up in the next week or so for a wedding planner friend of mine.


Belinda, I never had a big sister, but if I had one, I'd want her to be just like you :)

Always willing to lend a helping hand :D Good luck on your glass job, I hope it goes better than mine did. In all fairness, the large pieces went fine. It's the small text that killed me. Enough power to do what you need it to do to the glass and it blows out the text and makes it look fat (too fat). Knock the power down so the letters are sharp and crisp and it's not enough power to make the glass do what it needs to. It's gone now. They were very happy with all the items, so all in all, a happy customer, which is more important to me than money (Although I really like money).

Michael Hunter
09-21-2010, 10:11 AM
Unfortunately, the Wiki thing appears to mix the properties of glass and stone.

Glass is supposed* to be amorphous (i.e. the same all the way through) and non-crystaline.

* Should be true of window, bottle and similar everyday water-clear glasses.
Very old glass (Roman era) appears to grow crystals within it (and is no longer clear).

I'm interested in Dan's explanation - I had previously assumed that it was simply thermal shock that cracked the surface and lifted chips.
Dan's theory of melting/resetting, plus Paul's microscopic observations together make a convincing argument as to what is really happening - and fits well with lower resolution/dither patterning giving the best practical results.

After an accident (on a customer's piece:mad:) I am aware that a 60W laser can easily melt glass - as well as shattering it!

Belinda Williamson
09-21-2010, 10:35 AM
Belinda, I never had a big sister, but if I had one, I'd want her to be just like you :)

Thank you Steve. Considering how many times you have played "big brother" and defended me I believe we can officially adopt each other.

My glass job will be easy but I know who to call when I need to vent about it anyway. I only have to engrave a single large initial on a square vase (six of them), and the vases came from a local craft store. Knowing my luck though if I have a catastrophe the store will not have them in stock.

Dan Hintz
09-21-2010, 11:09 AM
Glass is supposed* to be amorphous (i.e. the same all the way through) and non-crystaline.* Should be true of window, bottle and similar everyday water-clear glasses.
It is, unless it's tempered... at that point, all but the outer skin becomes ordered and properties change. Either way, hitting glass of any kind with the laser reforms the liquidous state (and removes any properties previously engineered in), and the quick cooling afforded by keeping it in the open air (rather than a temp-controlled oven) leads to a buildup of stresses at the shallow interface between glass and air. That's what pops...

Very old glass (Roman era) appears to grow crystals within it (and is no longer clear).
I'd have to see it to be sure, but I highly doubt anything is actively growing within the glass (crystal structure wise). It's most likely it was never clear to begin with. Old glass was not exactly pure and was used to allow light into a room, not necessarily a clear view of the outside world. Even during the days when optics were first being constructed, keeping the pot pure wasn't exactly easy... grains of still-cold sand (or other metals) would fall in as a block was being removed, it may have been smoothed over a hand-sawn log, etc.

I'm reminded of the old wive's tale that glass is a slow-flowing liquid, and "proof" is the panes of old glass that are thicker at the bottom than the top. The most likely explanation given these days is it was actually used for shadowing effect by the artist and installed with the thicker side down on purpose... proof of that is seen by a few old pieces being found with the thick side at the top. Flipping each piece top to bottom really throws the artistic effect off (I've seen a few Photoshopped images that show what the final image would look like if the pieces were randomly placed or all were used with the thick part at the top... it's a huge change in effect).

TONG LI
09-21-2010, 12:21 PM
Ouch! Not only a party foul, but a machine cleanup and embarrassment factor, to boot...


EDIT: I find the timing of this thread somewhat amusing considering I'm currently working on my book's chapter on glass processing...

Clean up, yes, but no embarrassment. I displayed the broken beer bottle and told visitors, this laser machine can drink a beer and keep working, just like you, it is a working horse. Two blue Jeans kind of guys bought the machines at the show, lol.

It is not what you sell, it is how you sell it.

Tong

Joe De Medeiros
09-21-2010, 6:17 PM
the quick cooling afforded by keeping it in the open air (rather than a temp-controlled oven) leads to a buildup of stresses at the shallow interface between glass and air. That's what pops...

When glass is cooled from a liquid state, it needs to hold at the anneal temperature for a set amount of time to release the stress, then slowly drop at 100deg/hr past the stress point (700 TO 800deg) depending on the glass, as Dan stated the temp drop is uncontrolled, and as it reaches the stress point it pops, or semi pops (missing letters).





I'm reminded of the old wive's tale that glass is a slow-flowing liquid, and "proof" is the panes of old glass that are thicker at the bottom than the top. The most likely explanation given these days is it was actually used for shadowing effect by the artist and installed with the thicker side down on purpose... proof of that is seen by a few old pieces being found with the thick side at the top. Flipping each piece top to bottom really throws the artistic effect off (I've seen a few Photoshopped images that show what the final image would look like if the pieces were randomly placed or all were used with the thick part at the top... it's a huge change in effect).

Most of that glass was hand rolled, so I'm sure it depends on the dirrection that it was rolled in, I get hand rolled glass from Bullseye, and it has a rolled edge that is thicker. Maybe it was just common practice to put it fat side down.

Dan Hintz
09-21-2010, 8:59 PM
the temp drop is uncontrolled, and as it reaches the stress point it pops, or semi pops (missing letters).
It is possible to "pop" some of the stressed points that haven't passed the threshold themselves after cooling by rubbing with something a little hard (steel wool, paper crumpled into a tight ball, etc.). There should be few points that don't relieve themselves, and if you're unable send the remaining few over the edge by rubbing them, you need to increase your power.

Joe De Medeiros
09-21-2010, 9:32 PM
It is possible to "pop" some of the stressed points that haven't passed the threshold themselves after cooling by rubbing with something a little hard (steel wool, paper crumpled into a tight ball, etc.). There should be few points that don't relieve themselves, and if you're unable send the remaining few over the edge by rubbing them, you need to increase your power.

Luckily I don't do signs. but here are some of my Dichroic glass jewelry

Robert Walters
09-22-2010, 3:59 AM
glass "etching" comes from localized surface tension. The laser heats up the surface of the glass to the melting (flow) point...

Is this "reflow" the same process for granite and marble as well?

I swear someone at one time mentioned "micro fracture", but I couldn't tell you the context if I tried. Something to do with the percentage of quartz crystal in the medium.

Dan Hintz
09-22-2010, 6:11 AM
Gorgeous work, Joe... now I really wish you were closer. If you ever make a trip south of the border, let me know and I'll have the beers waiting.



Robert, Doubtful, but I'll have to think about what process is actually going on there...

Makrel Johnson
06-03-2016, 8:07 PM
Because I didn't find any recent rotary stemless frustration - I'll tag on the end of this...plus it was nice to know it's not just me.

Just (finally) completed a job of stemless red wine glasses and it was the first (and maybe last) order of this type. These were colored glass made by Lenox and not only were a pain, but stunk up the place while engraving.

Fun part was that the 'typical' glass speed & power settings turned out to be equivalent to a death ray as it cracked 2 right off the bat. This was after tinkering for what seemed like days trying to get the Epi rotary to not swing the glass like a club when it rotated, courtesy of the rotary clamp, and find a way to level the surface enough to not have ghosting. On these, if the focus was out even slightly - the lettering would only shoe an outline and not fill. Weird. It would also lighten up as if the power dropped at certain sections of the script.

Anyway - Scott I feel your pain...BUT - I now know more now than I did when I started, and have spares to work on a reusable jig with. I hope that it makes these things less of a MASSIVE Pain.

Live & Learn.

-Mak

Don Corbeil
06-04-2016, 11:07 AM
Flat glass is fine. Can do multiples pretty easily.
It's the drinking glasses that bother me - the time it takes to do them individually in the rotary requires large blocks of time. The thought of starting in on a few cases of pint glasses just makes me wince. It also ties up the machine so that I can't easily do flat work without removing the rotary and changing settings back.

Bill Cunningham
06-04-2016, 1:44 PM
The only piece of glass that has ever caused me any problem was a very thin ridel(sp)? Wine glass that a customer wanted a photograph on. The photo came out perfect, but after I gave it a light wipe, it literally fell apart in my hands. So, I redid it on a heavier glass and no problem. There is picture of this job posted here someplace. Other than that, every piece of glass I have put I my laser that started with a good photo, has come out perfect .. Ya I'm bragging :D For text, use 600 dpi

David Somers
06-04-2016, 2:31 PM
Hey Bill, I am always amazed with the results you get consistently from glass. I havent played with glass yet, but will at some point when some time presents itself. But in the meantime I keep watching what others are experiencing, both on this forum and folks who do it locally, and every time the results I see are so inferior to sandblasting I just dont understand what is going on. Like you and Dan, I know a very few who seem to be able to do it consistently well, but most flail at it and get pretty disappointing and often highly variable results. And these are people who I know approach something like this methodically and carefully, bracketing around techniques looking for the sweet spot that gives them good results, and they have good luck with every material they play with. Except of course, glass! I also noted that when I could compared well lasered glass against sandblasted glass the sandblasting is clearly better. Have you had a chance to compare your engraving on glass against similar efforts with abrasives? Just curious. It also seemed that the abrasive work I have seen was much faster than lasering glass. Any thoughts on that?

It is fascinating to follow. Someday, I will be so fascinated I will try it myself....drawn like a mouse to the gaping jaws of a snake I suppose. <grin>
Thanks for sharing all your techniques in that earlier post BTW. I have saved that for when I hear the siren call of glass engraving.

John Bion
06-06-2016, 8:13 AM
Scott, I see Rayzist in your future...... :)

Bill Cunningham
06-20-2016, 8:36 PM
Sorry it took so long to get back you, busy,busy,busy... I do mostly photographs on glass, it's my speciality, and I have never seen a piece of sandblasted glass that can even come close to the detail I can achieve with the laser. A sand blast mask will not hold a stochastic screen fine enough for really high detail. Sand is great for text & line art, but with proper image correction for detailed work the blast masking falls way short. There is lots of my work posted here but I have yet to see anything close to the detail done with a sandblaster. If anyone can show me, I would be fascinated to see how it's done.

John Bion
06-21-2016, 3:06 AM
Hi Bill,
I bow to your expertise in photographs :) I will freely confess that you and a couple of others, do outstanding work with photos on lasers. I do however think that for text, logos etc, there is nothing like sandblasting for a perfect finish every time. Almost never a reject and customers love the resulting depth and crispness.

Ivan Pavletic
07-05-2016, 4:51 AM
I believe that engraving depends of a glass quality. Every year we get to engrave the same glass plaque that has those magic letter syndrome. I have tried different dpi, speed, power and letters keep behaving like ninjas. And this year, same plaque but it was good after first try! all of them! I do not know how did this happened because I have settings in software for this tippical glass. Well, you learn very day something new.

Dennis Watson
07-16-2016, 2:34 PM
I just installed a sand blaster myself after having my 80w laser for many years, and I tried some window glass in my laser, and just a few minutes ago I tried the same image in the blaster, well the blasted looks the best.

The laser looks watered down, or not a white as the blasted does.

I like the idea of using the laser for flat glass, no stencil to cut and position, no having to put on the gloves, and not having to peel the stencil off.
I will keep both though.

Jimmy Phillips
02-17-2017, 7:28 PM
I don't do a lot of glass, but for what it is worth this seems to be a pretty good article:

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

Jimmy