Lasering glass

[Alan Young]

<!--StartFragment -->I have read that the laser is not the best way to etch glass. I was trying to do a couple of award plaques on glass that I bought. The awards catalog said it was laserable but did not explain it any more. The problem is it is not very opaque. Would several passes at a lower power be better than one at a higher power. I was using 80s and 70p and was getting so so results.

Alan

[Laura Zaruba]

Hi Alan!

I have a 35 watt machine and run at 30S and 100P. I usually put a wet paper towel over the glass before I laser and that helps a lot too.

Hope that helps!

[Mark Plotkin]

Alan,

I have been lasering glass and it comes out okay at best even with the wet newspaper or dishwashing soap applied to it. I just got a sandblaster and a large compressor. I am using Laser Tape on the glass. I just ran some samples on two wine glasses one at 300dpi and one at 600dpi with the mask and then sandblasted them. They both came out great and when I put a blasted glass next to an engraved only glass there is no comparison! the blasting is the way to go. It feels better and looks better especially from the back side. More toys I know, but if you are going to do a lot of glass work??

good luck
MP

[Shaddy Dedmore]

I've had slightly better results than so-so by using that paper tape and misting it with water. It also got pretty frost by using a higher resolution (more microfractures in a given area than lower res). Maybe a slight out-of-focus will spread out the fracturing also, but I don't know for sure on that one.

Shaddy

[Joe Pelonio]

My experience is the same as others, on glass the laser is best for objects that are hung in a window or on actual window panes, if it's mounted onto something like an award the contrast is just not the same as blasting or even chemical etching. With my stained glass hobby I sometimes will apply
a vinyl-like mask such as 3m calmask to the glass, then vector cut it on the laser, weed and apply the chemical etch available at stained glass supply stores. The result is probably not as deep as laser but more opaque. For blasting you can get an airbrush-like sandblaster that's
enough for small pieces, or a bucket fed gun that's under $50 at the
big home improvement stores that are good enough for glass.

[Mike Mackenzie]

Here is a trick that everyone should try when doing glass. Change all of the solid black areas to a 70% grey.

You WILL be surprised by the results. We also run 100 power and 30 to 40% speed.

[Alan Young]

Great idea's. Not sure I have a demand for a sand blaster but sounds like a possible new tool . I'll try the 70% gray and the wet news paper, never tried soap. Of course you always find this out after you ordered the blanks and the customer needs them I guess that is how we have all come up with our expertises, T&A (you know the Trial thing)

Alan

[Lee DeRaud]

Here is a trick that everyone should try when doing glass. Change all of the solid black areas to a 70% grey.

You WILL be surprised by the results. We also run 100 power and 30 to 40% speed.

(scratches head) Doesn't that do the same thing as dropping PPI by 70%?

[Bruce Volden]

I've lasered my fair share of glass / mirrors over the last 10 years. I have come to the conclusion (with my machines) that 25% pwr, 60% spd @ 200 DPI produces the EXACT SAME results as 100% pwr, 1% spd or any combination thereof! Increasing the DPI yielded ~ Nothing ~! I believe we're only fracturing the polished surface and since we have little control in how the surface fractures I prefer to go for speed and faster turn-around time. Some glass works VERY well under the laser, some are a total waste of time. I also laser the glass dry, I think it works so well for me because by lowering the DPI, increasing the spd, lowering the pwr results is less "dwell time" over the material. Try rastering acrlyic @ 100% pwr and 10% spd- it puddles right? I know, apples / oranges, but the energy is readily absorbed by the acrylic. No matter how much power is applied to the glass you're only going to engrave so deep (the surface). Or, (and this has happened in my early trials) the glass will crack or shatter! The grayscaling that was mentioned earlier is right on. Sorry so long. $.02 worth


Bruce

[Mark Mullis]

If your are going to sand blast wine bottles and such, can you laser engrave the mask flat, and then apply it to the bottle? Or do you need to apply it to the bottle and engrave the mask in place using a rotary fixture?

[Keith Outten]

The Badger airbrush folks make an Abrasive Sprayer Set, model #260-3 Mini Sandblaster that will blast at 20 to 30 psi. The kit sells for $39.00 and includes a can of air for remote work. Northern Tools sells Badger Sandblast kits.

[Jerry Allen]

Mark,
I tried cutting the mask on laser tape, but centers are too hard to keep in place. Since then I just laser on the bottle (or whatever).

To all,
As I have stated before, I tried everything, wet paper soap, with unimpressive results. So I just cut the mask using the laser and then blasted with excellent results.
Then one day, I just lasered the glass with Raysist laser tape at a fairly high power and speed, and the result was considerably better than low power with water and/or soap. Not as good as blasting, but good enough if you don't have a blasted item side by side. I think it's an acceptable method for certain uses.

[Alan Young]

I think I am going to buy a small blast cabnet to do glass. I do not do that much yet and figured this would be a good way to get started. For around $150 I can get something going. Know I need to just figure out the best resist. I am sure a lot of that will depend on the type of depth need.

Alan

[David Takes]

You will want to use a resist that does not contain PVC. Polyester laser resists are available from Specialty Tapes, Photobrasive, Rayzist, among others. I personally have taken a liking to the Laser's Edge Mask from Specialty Tapes.

[Kim Maitland]

Has anyone found Laser Tape for a lower price than Laser Bits sells it for? The application I'd be using it for is to laser glass and then sand blast it.