Acid Etching Glass

From Hack Manhattan Wiki

Glass can be acid etched easily using environmentally friendly Armour Etch™.

Etched glass will show a frosted surface where the acid has been applied.

Etching is particularly effective on flashed glass (a thin coat of colored glass has been fused to a base layer of clear (white) glass as the colored layer can be completely removed leaving a fogged window of clear glass. But flashed glass can no longer be obtained locally and is particularly dear.

Back surfaced mirrors can have the mirror removed to create artistic effects but the process is more involved and requires the use of different, less friendly, and more costly chemicals.

Create a Mask

  • You will need a mask/resist/stencil to protect the areas of the glass that you do not want to be etched and to expose the areas you do want to etch. Think of the time when you were in high school and they made you have your name stenciled on the back of your gym shirt.
  • You can create your own artwork or download something from the Internet.
  • Artwork that contains small areas that will not be etched will be a lot harder to deal with than big blocky designs as there will be lots of small mask areas that will need to be transferred to the glass in the proper registration
  • The artwork will need to be transferred to the mask material before it can be cut. Self adhesive vinyl makes a good mask material as it is easily cut and adheres well to the glass. It can be obtained in 1-foot square sheets from Michaels (or Amazon) for about $3/sheet.
  • The vinyl you use will depend on how you are going to transfer the artwork, which in turn depends on how you are going to cut the mask.
  • If you are going to cut your mask by hand you can draw your artwork directly on the vinyl but that may require a rough or matte textured vinyl.
  • If you are going to cut your mask electronically you can use a smooth, gloss surfaced vinyl.
  • Electronically cut masks are the easiest to make.

Electronic Masks

  • For my experiment in acid etching I went to a sign maker to inquire about having the mask cut professionally. They could and would cut me a small mask. But there was a $275.00 setup charge no matter what size mask I was having cut. I could buy my own DIY vinyl cutter for that.
  • I was walking up Seventh Avenue past FedEx Office and stopped in on a whim to ask if they cut vinyl signs. They avowed that they did everything and what I wanted was a contour cut from a SVG file which should only cost me around $6.00 for a 12"x12" "sign".
  • I created my SVG and went back and the next person I talked to wanted a PDF or similar that had to be sent out to a third party (FedEx Office doesn't actually do everything) for a quote. The quote never came back.
  • The two main DIY vinyl cutters out there come from Silhouette and Cricut, and we don't have either of them. I emailed my friends at NYC Resistor and was told they thought they had a couple of them
  • I made a field trip to Brooklyn stopping at CircuitCity, Harbor Freight, a stained glass shop, an art supply store, and finally NYC Resistor for [| Craft Night] where I found that they do have a Cameo vinyl cutter
  • I downloaded the free Silhouette Studio software which can be used to create the artwork and then drive their Cameo cutter. I found the software to be both powerful and easy to use
  • After importing my artwork into Silhouette Studio I had it traced to create my cut lines.
  • I made a trip up to Michaels and picked up a couple of sheets of 12"x12" vinyl. The cut lines from the cameo are very fine and the backing paper on the vinyl is white so a colored vinyl might make it easier to see the cut lines down the road. Since the vinyl mask will removed after the glass has been etched it doesn't make any difference what color it is.
  • Back at NYC Resistor on another Craft Night I set up the Cameo, connected it to my computer, followed the on-screen prompts and quickly had my mask cut.
  • The Cameo was easy to use and a bit noisy - but not router noisy.
  • Cutting the mask is just the first half. Next you need to remove the portions of the mask where you want the acid to get to the glass. This is a process called weeding. Having old eyes, I weeded my masks under the dissecting microscope, using a dental pick to pick off the unwanted vinyl. You can also use a dissecting needle, the point of a hobby knife or even the point of a safety pin. You just need something with a fine point that you can easily maneuver.

Transfer the Mask

  • Start by making sure your glass is clean. Any oil on the glass can keep the mask from properly adhering and later the acid from getting to the glass. Use an alcohol wipe.
  • Once the mask has been weeded, what remains needs to be transferred to the glass where you want to make your etching.
  • The mask is likely to be in multiple pieces and the vinyl is a bit stretchy so to get everything properly registered on the glass you need to use a sheet of transfer tape or paper.
  • Transfer tape is best as it is clear so you can see through it to properly locate the mask on the glass. It is adhesive backed but its adhesive is not as adhesive as the adhesive of your mask.
  • Using a piece of transfer tape larger than the mask, peel the paper backing from the transfer tape and carefully place it over the mask.
  • Turn the transfer tape and attached mask over and, using your dental pick/dissecting needle/craft knife/safety pin, carefully remove the paper backing from the mask. The vinyl mask should remain attached to the transfer tape.
  • Turn the transfer tape and attached mask over again and carefully place it on the glass in the proper position.
  • Smooth any bubbles out from under the mask and then carefully peel off the transfer tape using your dental pick/dissecting needle/craft knife/safety pin to press onto the glass any corners of the mask that might have been lifted with the transfer tape.
  • Once the transfer tape has been remove burnish the mask to insure that it is firmly attached to the glass paying particular attention to the edges. This is like attaching a vinyl screen protector to a cell phone, if you are old enough to remember them, so you can use a credit card or, if you have one, a brayer.
  • When everything looks good use some electrical tape to mask off an area around the mask to give yourself a safety margin for any drops or dribbles of acid.

Etch the Glass

  • I didn't find Armour Etch at either Michaels or Blick so ordered it from Amazon. It comes in at least two sizes and there is no mention fo an expiration date so I went with a 10 oz. bottle for around $15.00. There may be some of mine left in the flamables cabinet on the third shelf down. If you use it please feel free to replenish it so there is sufficient there the next time I want to etch.
  • Protect your work area from drips and spills.
  • This stuff is a paste with a consistency that is probably close to yogurt. Not being able to remember it name I call it goop. It will stay in place on flat glass and slightly rounded glass, but not vertical glass.
  • I think the YouTube videos recommended a sponge paint brush but I used a small, moderately stiff-bristled, generic art paint brush that I already had. The sponge brushes might be cheaper and there is no danger of the goop migrating under the ferule and interacting with the metal.
  • I started toward the center of my mask and drew the goop out to the edges to try to make sure that the goop got all the way to the edge of the mask without leaving any air bubbles.
  • I didn't find that the goop really wanted to adhere to the glass and my brush strokes would leave bare or barely covered glass behind so I kept going around the mask reapplying more goop
  • When I thought I had the glass well covered I really globbed on a thick layer of goop over the entire etch area and let it sit.
  • The instructions say let it sit for one minute. YouTube says longer. After 15 minutes I brushed the goop off down to bare glass and then put it back and let it sit for another 15 minutes. It doesn't appear to be fast enough acting that you can let it sit too long. I think Stephen got a good etch on new glass at 5 minutes.
  • When you are satisfied with the etch just wash the goop off the glass with tap water and remove the mask
  • If you plan to reuse your brush wash it likewise in tap water.
  • Clean up the work area making sure to clean up any dribbles of Armour Etch.
[| Charlie Ridgway]