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stan kern
10-24-2011, 10:54 AM
The posted video was good on engraving glass and doing it as a negative -- my question is can one just use flour and water and a sheet of paper to substitute for the special mask he used.
Is this just to keep it cool?

Martin Boekers
10-24-2011, 11:51 AM
The mask he uses is just a standard masking that most of us use for a variety of thing.
You can try flour and water, may be a bit messy. Some us dish soap (liquid) others a
wet newspaper. Not sure if the adhesive has anything to do with it.

One thing to remember that the adhesive is holding the tiny glass shardes so be careful
when removing it.

Dan Hintz
10-25-2011, 1:22 PM
The posted video was good on engraving glass and doing it as a negative -- my question is can one just use flour and water and a sheet of paper to substitute for the special mask he used.
Is this just to keep it cool?
I (and others) have tried about every mask available... my current belief is there is no valid reason to use the mask if you are simply engraving glass (no color fill). The white dots created are micro fractures in the glass. These are caused by the tensile stress of the glass during cooling after being locally melted by the laser. I posted a more lengthy response on this subject within the last year or so, if you want to search for it. If you cool the glass, you're forcing the laser to work that much harder, and it can even lead to larger localized fractures, fuzzing the picture out.

Michael Hunter
10-25-2011, 3:56 PM
We are all still waiting for THE BOOK!

Chuck Stone
10-25-2011, 4:55 PM
I'll wait till the signing

Paul Williams from Nunavut
10-25-2011, 5:27 PM
The posted video was good on engraving glass and doing it as a negative ...
Sorry, I missed the opening, I think. Which posted video? Thanks

Dan Hintz
10-25-2011, 7:45 PM
We are all still waiting for THE BOOK!
The cruise was H O R R I B L E!!! But I did manage to type up some some verbiage for the chapter on machine maintenance.

Martin Boekers
10-26-2011, 10:33 AM
Dan,

show us some of the glass you engrave.

I know many here do have issues with glass and try many things.
I quit carring a certain beer mug as some of the letters I engraved
dissappear depending upon the angle it is view at.
(I assumed that composite of the glass was the issue)

I have a similar issue with the black mirror I get. Soap does make a difference
and provide a smoother etch. You can run your finger across it and feel the
difference. I end up doing multiple passes with a quick brushing of the shardes
in between, that takes care of it on the mirror. I can't do multiple passes on the mugs
as the rotary never goes back to the same start position?

We want to see what you engrave, I don't recall you ever posting images. Especially the
glass as I know your stance on it's all in the setting.

"Show us the glass!"

Dan Hintz
10-26-2011, 12:20 PM
I posted a pic of a monogrammed Riedel Merlot (leaded) glass a couple of years back... no idea on the link, but the right search terms will likely turn it up. Try "leaded glass" with my name, possibly some other combinations. I don't get to keep much of what I do, and the tests are usually tossed after tuning... once I made enough to pay off the machine, I put it back into the "hobby" category and don't look for jobs (though I take them when they come in). SWMBO is now requesting I do the same with my woodworking tools ;)

After engraving, I rub a piece of brown paper (bag) across it for a few swipes to make sure there are no loose shards hanging on... not much you can do to lessen those. Your soap application (or rather, the removal of it) likely accomplishes the same thing. Quality of the glass does make a difference. Since the tensile strength is your workhorse in that application, a better manufacturing process will make it more even across the surface. Cheap glasses work well for most because the longer and more random fractures they give provide for a "whiter" surface. The Riedel glass engraving mentioned earlier is not as bright, and one might say it also "ghosts" at extreme angles. I'm okay with that, though, as the finer control allows for slightly finer detail.

Found it... post #12:
http://www.sawmillcreek.org/showthread.php?133432
Keep in mind the image is of a logo roughly 1" high, so that image is zoomed in quite a bit, and it was taken with a point-and-shoot standing next to the patio door... my DSLR didn't arrive until afterwards.

Mark Ross
10-26-2011, 1:27 PM
Soapy water in a spray bottle is what we use.

Michael Hunter
10-26-2011, 1:44 PM
I use tissue paper liberally soaked with water from a spray, my "favourite" settings and 90% grey instead of blacks.

Reason - With this method I don't have to worry about the "goodness" of the glass. Anything from the cheapest bottles through float glass and up to quality (but not lead crystal) glass ornaments gives similar results. Not necessarily the best results possible, but I don't have to worry about missed spots or flaking. I just put it in and it works.

Before, I used to do glass dry or with soapy water (which often dried off before the job had finished). I would get missed spots, so on the next piece I would ramp the power up and then find that I got flaking. It got so I didn't even want to try glass and turned down some jobs.

Mike Tavares
10-29-2011, 2:33 AM
Hi Stan,
I'm hardly on here !--?

Talking about glass, I do a lot of it!

When it comes to any, & a mean any type of glass,

It all comes down to Power Setting and Speed. (brightness and gamma) settings.

I've done thousands of projects! Everything from Beer mugs to photos on numerous types of glass and pieces.

What works best for me is: What type of image and substrate are you engraving on? (Glass)

I do, and I repeat, I do alot on glass. (best images are Black & white of course!)

That's right "Positives!

I don't change anything from the original image. Except, brightness, and Gamma" (convert it to grey scale with the right amount of brightness!& Gamma) I don't mask at all!!

If you start off whith a good image suitable for engraving, you will get good results. (original size, & dpi of image) to be engraved.

I've been doing this for about 18 years. ( started working and minipulating photos on first generation of Co2 Lasers) - early 1990's (also work and operate Yag aswell!) for same amount of time!

I Don't use soap, or any other lubricant of any sort!

Most of my images on a 45 watt Epilog engraver Co2 for glass are: Power=100% Speed=25% to 35% ---- with a 70% black to 90% black image.(on grey scale) (Brightness & gamma)

I take the actual image and resample it to the desired size, as is ! ( convert it to grey scale) and laser it!

I don't really care if it's cheap glass or expensive glass ---to me it's all the same.

Depending on whether it's mirror or an actual glass piece,-- just laser etch enough into the material to get your look.

That's all it really is! I don't bother with all the other stuff!----What works for you may not be the same for others.

If you need to use a mask, I feel it's because you don't have the right variables in power and speed-(Brightness and Gamma) I never use a negative image. NEVER!

When I do, I don't ever get the result I'm looking for!-----( maybe I'm on the wrong end of the spectrum?)

I should post some of my work on here to share with others!

I've learned that it's all about "fine tuning" like an instrument that plays music.

Practice, practice, practice!

I like to say, " If it's tooooooooo Hot! than it's NO GOOD! :) there must be a medium balance! (Such as Life :)


Somtimes the simplest of things ----are made to be over complicated!

(My point of view.)

I have learned alot by practicing and being innovative.

Let your ability run it's course !!

I know it can be costly !----but practice makes perfect! (or almost perfect!)

Just food for thought !

Hope this helps anyone out!

I have come to appreciate the Creek in my own time of need.

Good work to all who contribute.

Cheers!

Dan Hintz
10-29-2011, 3:40 PM
Brightness and gamma are strictly visual device settings, i.e., something you modify to make an image look better on a monitor, and will have zero effect on how the image engraves. For engravings, you should be modifying specs like contrast.

Martin Boekers
10-29-2011, 5:27 PM
Brightness and gamma are strictly visual device settings, i.e., something you modify to make an image look better on a monitor, and will have zero effect on how the image engraves. For engravings, you should be modifying specs like contrast.

Dan,

I'm not sure how this can have no effect on engraving, because when you adjust the brightness and Gamma you
do change the file. Any time you modify a file it has to effect the outcome. When you adjust the Gamma levels
doesn't that in effect flatten or increase the contrast of the image? Doesn't adjusting the Gamma adjust the black level?
Wouldn't this have a similar effect as setting the black at a lower percentage?

I guess the whole point is to keep the file in range of what the substrate can resolve.

Dan Hintz
10-29-2011, 8:44 PM
Dan,

I'm not sure how this can have no effect on engraving, because when you adjust the brightness and Gamma you
do change the file.
This is what I get for coming from a video world... one tends to forget that terms are used interchangeably in the print world (even if they're not exactly appropriate). So, I'll retract my prior statement with egg on my face. :o