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Annette Plamondon
02-09-2011, 11:27 AM
I have to engrave on some optical round crystal awards and the front of them slant so it is not level. I know I have to get it level before engraving it but my question is do I engrave on the back of the award just like acrylic or do I engrave on the front of it?

My boss who doesn't know much about engraving, neither do I, says I should engrave on the front but I thought it would go on the back....

This is the award I am engraving on. I also have the settings 100% speed at 25% power. I am using a 30W laser

I am new at this!181963

Mike Null
02-09-2011, 11:30 AM
I prefer to engrave the back and do so on all crystal, glass and acrylic awards.

In order to position this securely I would put the base at the back ruler of the table and the left edge against the left ruler. I also use transfer paper or leave the original paper in place and run a test at low power so that you can check the placement of the art. Your art will have to be mirrored and flipped upside down.

Sorry if I've mentioned things you already know.

(I also agree with those who have later posts that sand blasting is the preferred method of marking crystal and glass.)

Ross Moshinsky
02-09-2011, 11:44 AM
Be careful lasering crystal. It's tricky. Most people sandblast it.

Gary Hair
02-09-2011, 12:06 PM
First, I would sandblast it, not laser it. Second, I usually etch the back side of any clear material, glass, crystal, acrylic, etc.

Annette Plamondon
02-09-2011, 12:08 PM
I don't have the means of sandblasting :( I don't even know how it is done.

Dan Hintz
02-09-2011, 12:37 PM
It comes down to personal preference, and I prefer engraving the back. The front of the award is wiped down the most often, so I don't want grime getting caught in the engraving every time.

Bjorn storoien
02-09-2011, 1:03 PM
i do a lot of glass and crystall

front or back ? do it the way you like it

the awards are usually all glass (you wouldnt get crystal at that price Crystal just sound better in the ad)

The problem with Crysal is the amount of led that can give scary results on expensive vases etc

the most common problem is that one letter in a line of text will get engraved with no contrast ( looks like clear glass)

when i do Crystal i am always prepared to do a second run with new paper (wet ) and same settings
first run let it dry and inspect for bad spots

i have always been able to fix it with a second run !

Bjorn

Robert Walters
02-09-2011, 1:14 PM
Ok, I see this mentioned all the time, but I don't understand why...

What is the *purpose* of the wet (soapy) paper when engraving glass?

Annette Plamondon
02-09-2011, 1:38 PM
Yeah, I have tired a wet newspaper set over the top of glass and nothing happened. Maybe I did something wrong. I have also tried some dish soap and I didn't notice much of a difference.

Dan Hintz
02-09-2011, 1:52 PM
What is the *purpose* of the wet (soapy) paper when engraving glass?
Some believe they get better quality engravings with it. It's a long-standing tradition in the laser world, and while some swear by it, I (among others) have proven to myself time and time again that a quality engraving is possible without a single drop of soap, water, or bundle of newspaper.

This method stems from the belief that the glass fractures are reduced in size by cooling of the water trapped in the paper. In reality, however, the water serves only to reduce the strength of the beam power hitting the substrate and would have negligible effect on cooling of the glass (the fracturing is a localized surface phenomena).

Mike Null
02-09-2011, 2:03 PM
I tend to agree that the paper and water trick is of questionable value but as Dan says, many swear by it. I believe settings and resolution determine the engraving quality and it takes test upon test to find the sweet spot--which varies by glass.

Joe De Medeiros
02-09-2011, 4:51 PM
kind of off topic

Just thinking out loud, when I work with Float Glass, it's important for me to know which side is the Tin side, otherwise I get poor fusion in my kilns, so I'm wondering if this may play a role in poor engraving, kind of like lead crystal. Anyways To identify the tin side of a piece of float glass shine a short wave ultraviolet (UV) light on it. The tin has a higher UV reflectance than the glass and will appear white and cloudy. I would test this out, by my laser in storage until the spring. One other less scientific way to test the glass is to lick it, that's right lick it, it will have a metallic taste on the tin side, just make sure is clean.

Bill Cunningham
02-10-2011, 10:41 PM
Some believe they get better quality engravings with it. It's a long-standing tradition in the laser world, and while some swear by it, I (among others) have proven to myself time and time again that a quality engraving is possible without a single drop of soap, water, or bundle of newspaper.

This method stems from the belief that the glass fractures are reduced in size by cooling of the water trapped in the paper. In reality, however, the water serves only to reduce the strength of the beam power hitting the substrate and would have negligible effect on cooling of the glass (the fracturing is a localized surface phenomena).

I find that it doesn't so much improve the engraving quality, but when I brush some dish soap on glass before etching, I don't seem to get powdered glass accumulating in the machine. I do a lot of glass, and I wonder if the surface soap vaporizes when the beam hits it, and in it's vapor state collects the fractured glass dust off the surface, and allows it to be sucked out the exhaust more efficiently. It does not seem to make a difference if it's dried on the surface, or still gooey. Before I started using soap, I was always finding quite a bit of white dust/powder glass in the cabinet. The soap seems to help keep it in the airstream and spew it out of my building, where I assume it may keep the lawn bugs in check like a cheap diatomacious earth:rolleyes:

Bill Cunningham
02-10-2011, 11:22 PM
kind of off topic

Just thinking out loud, when I work with Float Glass, it's important for me to know which side is the Tin side, otherwise I get poor fusion in my kilns, so I'm wondering if this may play a role in poor engraving, kind of like lead crystal. Anyways To identify the tin side of a piece of float glass shine a short wave ultraviolet (UV) light on it. The tin has a higher UV reflectance than the glass and will appear white and cloudy. I would test this out, by my laser in storage until the spring. One other less scientific way to test the glass is to lick it, that's right lick it, it will have a metallic taste on the tin side, just make sure is clean.

I was not aware of the difference. would this also allow one side to accept paint better than the other?

Dan Hintz
02-11-2011, 7:53 AM
I find that it doesn't so much improve the engraving quality, but when I brush some dish soap on glass before etching, I don't seem to get powdered glass accumulating in the machine.
Now this is a statement I can get behind, and it makes great sense. A thin layer of liquid soap would probably do wonders to prevent shards from shooting off to the sides.

Joe De Medeiros
02-11-2011, 10:48 AM
I was not aware of the difference. would this also allow one side to accept paint better than the other?

I don't know about paints, but when I try to fire enamels, it won't work properly on the tin side.

Bill Cunningham
02-12-2011, 10:31 PM
I don't know about paints, but when I try to fire enamels, it won't work properly on the tin side.

I know the krylon fusion seems to stick to glass, however it may chip off with temperature change. I assume it may be due to the expansion/contraction difference. I never thought much about paint on glass, but I just finished a fair size order for a glass blower/caster up in Tory hill.. This was not float glass, but 550 cast glass pieces that were laser engraved, then coloured. On one of the samples I did back at the start, I sprayed the smooth back of one of these pieces with black fusion to see if there would be better contrast. Sometime during the next week, the piece was subjected to -25c and some of the paint flaked off the back so that killed that Idea.. I think they ended up using Rub n Buff to colour the etching in Gold, Silver and Bronze. These were made for awards in the Ontario Seniors Winter Games in Haliburton this Month.. I was a fun job, and profitable for me.. I have a few float glass pieces I have done through a painted surface, I'll have to check them and see which side was painted and etched, then maybe try a few experiments..

Bill Cunningham
02-12-2011, 10:34 PM
Now this is a statement I can get behind, and it makes great sense. A thin layer of liquid soap would probably do wonders to prevent shards from shooting off to the sides.

I still get 'some' dust, but that's the only variable I have introduced to the glass etching process. Since then, the glass dust is not a problem..