Laser VS Sandblast

[James Aldrich]

Hi all

We were wondering about the quality of laser etched photographs compared to sandblasted. We are wanting to get a laser for etching on glass and marble tiles. We currently play around with sandblasting, but is time consuming. Compared to halftone sandblasting, how well would a laser do on glass? I attached a photo I took with a digital camera, this is what I started with, and a photo of an ornament that I sandblasted using halftones. The ornament is 3.25" in diameter and the etching is 2.25" in diameter. Any information would be greatly appreciated.

[Joe Pelonio]

Doing a photo image the laser takes a long time, but it's run time that you can be doing something else. Unless you have a lot of power you won't get the depth of sandblasting. You should have a couple of Laser sales people run samples for you using that same file, so you can compare, or maybe a member with laser in your area would do it for you. There's a list of laser owners at the top of the laser forum, you can PM if you see one or more in your area and ask. I have done sand on glass and acrylic but mostly on wood, and it sure is a lot messier.

[Mark Plotkin]

I currently own an epilog mini 45w. I was an awards show this year and did some sandblasting to try it out. This week I ordered a tabletop blast cabinet to use in conjection with my laser. I plan to engrave and etch wine glasses and other glass products. Photo Brasive makes LaserTape which can be engraved to cutout the mask and then the sandblaster can add the depth to the glasses. I am not sure on the half tones for photos yet. I will keep you posted.

[Rodne Gold]

For blow your mind results , use the laser to ablate the mask while applied to the glass and then blast. You can do incredible detailed 1/2 toning with the right resist and the right lens and a decent conversion program like photogav.

A laser alone is lousy on glass due to the way it acts , it thermally shocks the glass with a pulse of heat and the glass fractures (not well controlled)

[Mark Plotkin]

Rodne,

Can you share some of your details:

Which mask works the best for halftones?
Do you use the glass prm. in photograv?
What speed and power do you use to burn the mask?
Any other details would be great!

thanks
MP

[Rodne Gold]

I use polyester vinyl for deep blasting and paper based vinyl application tape for light blasting and finer detial.
I use the light cherry with grain Prm (I find the paper and the vinyl act like wood with the heat affected zones being similar)
speeds and powers would be academic for you due to the different laser speeds and tubes etc , but generally for the paper its very high speed and slower for the polyester (the shiny non stretchy) vinyl.
I often use a 1.5mm lens with a smaller spot size. I also use a very fine carborundum grit.
The paper blasting is easy as the sligh residue the adhesive leaves can easily be seen to be cleared and when it does , its time to stop otherwise one can erode thru the paper. The paper mask comes off in a tick when wet , the polyester mask is very difficult to remove.
You cant get the same detail as lets say lasering marble , as due to grit particle size the dot of the halftone has to be big enough to allow the paerticle to hit the glass , often you need quite gross halftoning on the mask which actually translates into smaller dots as the grit particles "bonce" off the edge of the open area/dot and thus a smaller area in the middle gets blasted. Almost a compensation factor thing

[Garry Winterton]

tesa make a paper sandblast tape which is quite good and fairly cheap.
i couldn't find any mention of pvc's in their safety sheet
but you have to burn all the backing glue away to get a decent blast.
Depth makes the sandblasted image better in my opinon as you can get a better colour fill in it.
although a directly lasered image has more detail.

i have never being able to get a deep blast with laser tape.
i need to blast fast and quick and laser tape always seems to fall apart under any sort of decent pressure.