There are numerous ways to etch or engrave on glass, but laser, paired with a rotary attachment, has become the industry standard.
Laser engraving machines have come down in price and they come in many different sizes. They are user-friendly, acting like any printer except that when you design in the graphics software and hit print, they engrave instead.
Epilog Laser has been in business since 1988, “so we have a lot of experience when it comes to how a person uses our laser systems,” says Ben Sieber, senior graphic designer for the Golden, Colorado, company.
The firm's laser machines offer different settings that vary per system and wattages that help get the optimum contrast in mark when engraving with glass.
Epilog put together a tutorial that tells potential users of its laser engravers how to set up the artwork to make the best contrast while engraving.
“You can vary the contrast of the mark based on how gray or how dark of a gray you are using. Basically, each shape is a different color gray,” Sieber says.
He points out that the laser is actually micro fracturing the glass rather than engraving it. By varying the amount of heat and pressure, the laser can create a three-dimensional look.
“If you look at the mark up close, you will see tiny fractures that give you that acid etch look,” he says.
The artwork and its color scheme determine how deep or how lightly the laser will etch the glass. Black on the artwork translates to bright white on the etching because the dots are closer together, while gray is a lighter white because it spreads out the amount of dots the laser burns into the glass.
“This is one of the neater effects you can do when engraving glass with a laser. One of the other things that is nice about using a laser on glass is there are no additional steps. With our laser and the right settings, we are able to engrave the surface. We don’t have to surface prep or add masking materials,” Sieber says.
Adding a rotary attachment allows a shop to engrave cylindrical objects like cups, pitchers, mugs and wine bottles. In using a rotary attachment, you send your image to the laser like you normally would but now the rotary attachment rotates the item at small increments.
The type of glass used is very important.
Kurt Koser of Koser Enterprises Inc. in Morgan Hill, Calif., is a GCC laser distributor. He refers to glass as “the great unknown” when it comes to laser engraving. As a medium, every type of glass reacts differently to the laser. He says that even if someone brings 20 of the same glass for engraving, each one could turn out differently. Nineteen may engrave beautifully and the 20th will flake off around the etching.
“Glass can take a fair amount of energy. I recommend 100 percent speed and power on 30 watt. That will give you an indication of how that glass is working. Glass doesn’t need a lot of power, but it can take a lot of power,” he says. “The only way to know if an individual type is going to take it is you have to try it.”
Koser says that the laser isn’t engraving so much as shattering the top layer of the glass, which hazes and turns white.
“That’s how lasers mark glass. Sand blasting equipment is a polishing process. Polishing sounds better than shattering. I think polishing looks better than shattering. With laser, it is simple and fast and easy to mark glass, but I like the results better of the sand blaster,” Koser adds.
Dan Park, president and owner of Perfect Etch in Austin, Texas, says that sand blasting has been around forever. He calls the use of sand blasting on glass, sand carving.
“Like painting, you cover up the areas you don’t want hit with a sand blast and that’s the area exposed and modified,” Park says. “There’s pressure, sand vs. air.”
Sand carving is not done with a machine. It is done by hand.
One way to combine laser engraving with sand blasting is to use the laser engraver to etch the outline of a design into the glass and then use sand carving to fill in the design, says Epilog’s Sieber.
“You laser etch the pattern through the masking material and then hit that mark with the sand blaster to even things out and give it a nice smooth finish,” he says. “Even for a customer who uses sand blasting for everything, laser is a great tool. There are a lot of ways to create patterns with masking materials, stencils.”
Epilog sells premade stencils to its clients, but with the laser, a shop can create its own stencils “and the amount of products they can sell with customized graphics grows exponentially. You can make any pattern with a laser,” he adds.
“The laser is a great tool for any shop that processes a lot of glass requests. Even if you are using traditional methods, laser is a great tool for expanding the different styles of graphics you can create,” Sieber says.
Another option is to laser etch a design by masking off the product and adding a smooth coat of glass paint. Let it cure and then remove the mask, which yields the color, Park says.
“The important thing to keep in mind is that not all glass is the same,” says Josh Stephens who is in business development at Trotec Laser Inc.
One way to reduce chipping in the glass is to apply a wet mask to the glass before laser engraving.
“The mask can be newspaper, copy paper, transfer tape, etc. Wet the mask and apply it to the glass where the engraving will occur. An alternative to the wet mask is to simply apply dish soap to the surface of the glass prior to engraving,” Stephens says.
Glass with a lot of lead content, like crystal, is hard to laser engrave.
When more lead is present, “you get some areas within the glass that somehow overheat a bit based on the settings. With higher-quality glass, nice crystals, you get irregularities to your mark,” Sieber says. That’s when it is nice to combine sand blasting with the laser etching to give the crystal a nice smooth finish.
Laser engraving also can be used on mirrors, to either etch in a frosted design on the front of the mirror or to engrave away the mirrored coating from the back side of the mirror so you can see the design through the mirror. Color is then added to make the engraved message or logo stand out.
Sieber adds that many stained glass makers are using laser engraving to score the lines they want to cut through the glass. They then use traditional tools to break the glass along those lines.