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View Full Version : lasering on tempered or stained glass



Brian Knuckles
12-10-2009, 6:56 PM
hey there,

has only one tried to laser on tempered glass or stained glass?

I've lasered in the past on laserglass from lasertile.com but I need something that can be very 'artisy'

thx

Dan Hintz
12-10-2009, 8:37 PM
All glass engraves pretty well...

Joe Pelonio
12-10-2009, 11:22 PM
The smoother stained glass engraves well, the really nice textured (expensive) glass can't be focused well and of course the rough surface
especially in multiple colored patterns makes any images to come out with too little definition. Darker colors like blue turn out best.

Zsolt Paul
12-11-2009, 12:05 AM
Last year was my first try with tempered. Learned the hard way that its best to keep the dpi's low. I developed this white powder on top of the glass and the image left behind was pretty horrible. I did it at 300 dpi. I was told I should try 150 to keep a decent distance between the dots. Not sure what it is about tempered, but it acted differently than regular glass to me. I could do 300 dpi on reg glass, but not on tempered.

Dan Hintz
12-11-2009, 6:35 AM
Hmmm, I go to a higher dpi on tempered as it doesn't chip out as easily and holds a higher definition.

Zsolt Paul
12-14-2009, 12:11 AM
Strange.... perhaps it was the glass itself. I got this "flaking" on the surface of the glass. I literally had to wire brush off the white powdery stuff in order to clean it up. What power and speed setting do you use? I have a 100W. Max speed 50 ips. Just to clarify, I set the actual power and speed settings. NOT in percentages. Obv for power the two happenned to be the same since its 100W, so 35% is the same as 35W, but the speed is entered for what it is (40 is 40 ips, not 40%).

Do you use dishwashing liquid first?

Michael Hunter
12-14-2009, 7:58 AM
Stained glass engraves very well, but be aware that different colours may need different settings to give the best results.

The is an "old-fashioned" stained glass that I have come across occasionally. This is a clear glass with a very thin layer of coloured glass on one side. With brutal power settings it is possible to completely remove the coloured layer and the results can be outstanding.

Similarly, dichroic glass can be engraved to remove the dichroic layer which is effective for some colours. Also good for slumped-glass jewellery makers.

Have not tried tempered glass.

The "flaking" effect is a real nuisance - it seems to affect thick glass ("plate glass") the most, so of course it appears on the high value jobs most often. I have minimised its occurence by always using the minimum power to do the job, running at 300dpi and on suspect pieces using 70% grey instead of black.

Zsolt Paul
12-14-2009, 9:46 PM
Isn't reducing black to 70% gray the same thing as lowering resolution? 70% gray produces less dots (or dots with more spaces in between...same thing) than black, much like lower resolution produces less dots per inch. This would go hand in hand with what I was told to try, which is sub 200 dpi to avoid flaking.

Dan Hintz
12-15-2009, 6:44 AM
Isn't reducing black to 70% gray the same thing as lowering resolution? 70% gray produces less dots (or dots with more spaces in between...same thing) than black, much like lower resolution produces less dots per inch. This would go hand in hand with what I was told to try, which is sub 200 dpi to avoid flaking.
Noooooooo, not the same. Imagine a 1dpi image... you'd have a huge dot every inch, but the laser cannot make that dot with one laser pulse. It's going to create it using a number of full-power pulses in a circle (say you set the laser to use 200dpi). If you set that one dot to 70% gray, the laser would only fire 70% of the time when making up that dot from a large number of pulses. This is what reduces chipping, reducing the amount of heat in one area as well as reducing how close each "chip" is to the next.

Zsolt Paul
12-18-2009, 11:25 PM
Noooooooo, not the same. Imagine a 1dpi image... you'd have a huge dot every inch, but the laser cannot make that dot with one laser pulse. It's going to create it using a number of full-power pulses in a circle (say you set the laser to use 200dpi). If you set that one dot to 70% gray, the laser would only fire 70% of the time when making up that dot from a large number of pulses. This is what reduces chipping, reducing the amount of heat in one area as well as reducing how close each "chip" is to the next.

I understand what you are saying and thanks for the good explanation. I think I was trying to say something similar. Let me try this way and let me know if this is the same thing.

Take a 1x1" square. If this square is 70% gray and you engrave at 300 dpi, you will have 210 dots in this 1 sqin area. You'd have 300 dots if it were black, but with 70% gray you have 30% less dots = 210 (more or less). Correct?

If you change the square to black and engrave at 210 dpi, you will also have 210 dots in that sqin right? That's what I meant by lowering the dpi is the same as going from back to gray. Am I wrong?

Michael Hunter
12-19-2009, 8:08 PM
Sorry still wrong

If you engrave in black at 300 dpi, a one inch square will have 300 x 300 = 90,000 dots within it, all evenly spaced - and probably overlapping.

If you engrave the same square in 70% grey, the engraved dots are still on the same grid, but 30% of them are missing - in a psuedo-random pattern generated by the software driver.

A clearer example would be 50% grey : in this case - numerically - every other dot is missing. To avoid a strong chequer-board or criss-cross pattern, the driver again appears to randomise the missing dots by generating a pattern.
Engraving in black at 150dpi would fire the same number of dots, but all equally spaced, so potentially exhibiting a strong pattern.

Zsolt Paul
12-20-2009, 2:27 AM
Sorry still wrong

If you engrave in black at 300 dpi, a one inch square will have 300 x 300 = 90,000 dots within it, all evenly spaced - and probably overlapping.

If you engrave the same square in 70% grey, the engraved dots are still on the same grid, but 30% of them are missing - in a psuedo-random pattern generated by the software driver.

A clearer example would be 50% grey : in this case - numerically - every other dot is missing. To avoid a strong chequer-board or criss-cross pattern, the driver again appears to randomise the missing dots by generating a pattern.
Engraving in black at 150dpi would fire the same number of dots, but all equally spaced, so potentially exhibiting a strong pattern.

Got it! So its the "randomization" that makes it superior. The number of dots is the same but perhaps more appealing to the eye. Thanks!

Bill Cunningham
12-20-2009, 11:31 AM
A couple of years ago I did a whole bunch of names on small pieces of a wavy surfaced green blotchy glass for a customer that would then cut them to shape, and use them on some kind of dangley Christmas decoration.. The names all etched well, and frosted the normal white colour you usually see on glass..