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Bart Woodstrup
08-03-2007, 2:47 PM
I'm looking for some initial pointers if any of you could lend them. (I'm not a professional, so please excuse my lack of knowing proper terminology).

I am a student at a school that just received a very nice Vytek Special FX 100 watt laser. I'd like to use it to etch glass. So far I've etched glass using the settings I received from vytek. However they didn't give me much to go on...

Here's what I've tried:

I've made several files in photoshop - a grayscale tiff, a 50% threshold bitmap, and a halftone screened bitmap - each 300dpi. I then printed each through Corel (does the version # matter?). In the print setup I adjusted the power and speed for best results.

My problem is that it etched the image as a solid color (except for the 100% white areas) - by "solid" I mean without any of the tonal gradation or screen present in the original image. I adjusted the full range of power and speed settings which did change the amount of depth of the etch, but didn't add any tonal gradation. Any suggestions or is this too vague?

Is the Vytek able to adjust the laser strength to etch gradations or is it basically on/off? Am I working to small? (my image size was 3"x3")


Finally, I read in a Vytek manual that I should be placing a wet tissue when etching glass - but it didn't tell me where to place the tissue (above or below) or why to do it in the first place. Any insight?

I've etched glass on a smaller laser before (I can't remember the model #) and the image looked great - it was a small image and had a very good tonal range.


Any suggestions or if you can refer me to previous posts or other documents, will be mucho appreciated.

thanks

bbw

Mike Null
08-03-2007, 5:17 PM
Bart
There is a current thread called "JDS mirrored plaques" which would be helpful.

You'll probably get a dozen opinions here but here's mine FWIW.

The wetted tissue should be placed on the area to be engraved.

Unless you have a rotary device you'll find it's much easier to engrave flat items than cylindrical items. The focus is critical and the machine can go out of focus quickly on cyl. items. If you were doing a drinking glass, for example, the image would have to be realatively small for the machine to remain in focus.

I doubt that you're going to have a lot of success with gradient images on glass.

There are always pieces of glass laying around that you can experiment with and I would do that a lot to get a feel for the capabilities of the machine.

Bart Woodstrup
08-03-2007, 6:28 PM
Thanks Mike - that thread did answer some of my questions. When I etched with a smaller laser and got decent gradation, I could only see the gradation when I angle the glass in the light. This effect is fine for my purposes. I haven't been able to get the same effect with the Vytek though.

Regardless, I am thinking about experimenting with varying the DPI and working with halftones. This might be the best way to go. I also am thinking about doing multiple passes - each using a different power setting and etching different parts of the image. This might give me the best tonal characteristics - possibly similar to sandblasting? Now I'm worried about alignment... though I think the Vytek has some sort of anti shake mode that should help keep the glass in place.

It's a big Vytek (4'x4") and it can really rock and roll when it gets going...

thanks - keep the advice coming in if anyone has any.

bbw

Dan Starr
08-04-2007, 7:54 AM
Hey Bart,
I have the Vytek L-star, you should be able to get good results with the fx. Do you have photograv? That would help improve your results. You may also be running to much power, have you tried lasing a quality quide on the glass? Also with a 100w laser there is no need for the wet tissue.

Bart Woodstrup
08-06-2007, 3:31 PM
Hi Dan,

We don't have photograv, and because we are a school (and only I am engraving) I doubt we'll get it.

What so you mean by "quality guide"?


Thanks

bbw

Dan Starr
08-06-2007, 6:39 PM
In your DNC menu on the machine where you sort through the jobs, vytek should have included a file called quality guide. It is basicly 10 squares each with a different greyscale percentace from 0-100%, you etch it onto your material and then adjust your power and speed settings until you get good definition between the ten squares.