Sand carving can produce a deep etch, surface frosted or somewhere in between. What looks best depends on the product you are etching and the design being etched. The more delicate the product (thinner crystal for example) and thinner the lines of the design, the better surface frosting looks. Thin script fonts are good candidates for frosting. The mug to the left contains large surfaces to etch with broad-lined fonts. So it looks great when deep etched.
So what’s the process that leads up to the actual sand carving step? 80% of the sand carving process is the various preparation steps. After our client selects the product and the components of the design it’s time to do the artwork. Whatever we can get on our computer we can sandblast. We can scan an image, like a kid’s hand. We can choose clip art and perhaps alter it. Vector art which is made up of lines and shapes can be more easily changed. Bitmap art such as the photos you take with your digital camera can be much more challenging and time consuming to make changes to. The artwork can take 10 minutes or an hour to get the result we are looking for. Some of the challenges to the artwork step include fonts with extremely thin lines; the curvature of the glass (fast curves and multiple curves); and too much text and graphics for the size of the sand carving area.
Masking – Transferring the Artwork to the Product
Once the artwork is complete, how do we get it onto the mug? There are 3 primary materials, but we’ll cover the method we use for round objects like a beer mug. The artwork is printed on vellum paper. We use a laser printer with dry ink. The key is that the print is very dark and vellum paper accepts ink very well. The graphics on the vellum is then developed onto an expensive masking material. This is done in a light box exposing the film to a special light source. The dark graphics on the vellum is placed upside down on the masking material. Wherever the light hits the material, it hardens it. That’s why very dark print is important, as you don’t want the graphics that will be blasted into the glass to harden.
Next we’re going to get rid of the soft masking (the parts that will be etched) by washing it away. To hold the masking together during and after the washout there is a clear carrier sheet behind the masking. We use a hand pressure washer to wash away the soft masking. This takes about 5 to 10 minutes. The masking cannot be used until the masking dries. It is hung up like laundry and dries for a few hours.
The other two major masking types are sandblasting vinyl (either hand cut or cut by a plotter/cutter) and dry masking, which is great for sand etching photographs. We also use laser masking that is adhered to flat products and the design is lasered into the masking by burning away the design.
Applying the Mask
The last steps before sand carving starts with placing the masking on the glass. The masking includes a glue which eliminates the step of applying glue, but as a dry glue it makes it difficult to place the masking on the glass straight. When you add in a curved surface, it takes talent to get it right. There is some forgiveness as you can pull up the masking at least once until you apply pressure to the mask with a vinyl scraper. Remove the bubbles wherever possible. Next we use a rubber roller to make sure the mask is sticking well. Now we remove the carrier sheet from the mask by getting it to separate and then peeling it off. As you can see we need a separate mask for each item we sandblast. There are no time savings with volume except in the artwork. Often, that saving is limited as well as we have to change out names, titles, etc.
We’re not done preparing yet. Next we have to tape off all of the glass that won’t be sandblasted. We use a blue tape used by painters, as it sticks well, but removes easily without leaving much residue. Every little nook & cranny must be taped or you risk sand carving portions of the glass not intended.
Sand Etching or Carving
Now we’re ready to sandblast (sand etch). This is done inside of a special cabinet that pulls out the dust as you sandblast. The material we use to sandblast is either aluminum oxide or silicone carbide (our favorite). The size of the particles are measured just like sandpaper. We use sizes ranging from 80 to 180 grit. The higher the number the smaller the size of the grit and the more detail we can sandblast. The blasting material is blasted with air from a compressor with pressures from 20 psi to 80 psi. A mug would be blasted with 160 grit at 30 to 40 psi.
Sand carving or etching differs from laser engraving glass in that sand carving etches away the glass (or stone or other hard material) and can etched deeply. A deep etch is 1/16 to 1/8 inch deep. Even 1/32 looks deep. Laser engraving only cracks the glass in very minute dots. A somewhat similar look from sand etching is called a “frost”. A “frost” is not deep (like laser engraving glass), but it leaves a finer, more eloquent look then laser engraving does. Sand carving or etching is worth the small premium you will pay. Sand carving in our business refers to a more complex method that etches at various depths and frosts for a highly artistic piece.
The last step is clean-up and with some products, this can be a lengthy process. All the tape must be removed, then the masking which comes off in small pieces must be scraped off. Then we must wash the glass, dry it and clean it again with glass cleaner. Finally, we wrap or box it.
If this seems like a long process, you’re right. It is. This is why sand carved glass generally costs more then screen printed glass. With screen printing you make a mask for each color you are going to screen print and then use that mask over and over. You are usually charged a separate charge for each screen that has to be made. But if you want a large number of glasses with standard text or graphics, this is certainly a cheaper way to go. The drawbacks of screen printing is that you cannot personalize the product with a different name on each. They must all be the same. The second drawback is the look. Sand carving is elegant and has a much more expensive look. Both products have their place based on purpose, desired look and budget.