Introduction: Chemical Etching of Glass
Chemical glass etching is fun and easy. You get a frosted image that does not wash off but has no depth so it doesn't make the glass more fragile. I use sign making vinyl and a vinyl cutter to create a mask to constrain the area to be etched. Depending on the vinyl cutter, you can get a lot of detail and there is no problem with 'islands' - unconnected free-floating areas that are not etched if you use a transfer tape to move the vinyl to the glass. I have done the text for wedding glasses in cursive script - that is about as much detail as I could get. One downside is that it is hard to get a uniform fill of a large area.
I used our makerspace Silhouette Portrait after trying it on our Build Night to cut some vinyl. It is perfect for smaller projects like glass masking. Take some time to adjust the cut depth for the brand of vinyl you are using. Ideally the vinyl should be cut completely through so it lifts easily but there should be no cut on the backing, possibly just a slight depression. If you take the time to get the settings right once, weeding the waste will be much easier and your life will be better. Your pet might even like you more.
Step 1: Tools
You can see some of the tools you will need - sharp scissors, pointy implements for weeding the vinyl, transfer tape and the chemical etchant.
Step 2: Picking the Glass
The glass should have sides that are as near to vertical as possible. Curved walls mean stretching the vinyl mask to eliminate wrinkles - it is very hard to do and distorts the vinyl mask. Champagne flutes aren't bad. Beer mugs and water glasses work well.
I use mostly upcycled glass. Church sales, garage sales, thrift stores and Curbmart (free stuff left on the side of the road) all make for good and cheap shopping. I did buy a case of wedding glasses and beer mugs for special projects.
Step 3: Clean the Glass
If there is any sticky residue (from a price tag), use Goo Gone. Follow that with a glass cleaner and always end with isopropyl alcohol. Do not touch the etching area once it is cleaned. The oils from a fingerprint can create an uneven etch.
Step 4: Cut the Vinyl Mask
This can be done with a vinyl cutter, free hand with an Exacto knife or a purchased stencil.
Step 5: Weed the Mask
Weed out the area you want to etch. I use a sharp dental tool or hobby knife to spear the unwanted area and lift the piece out. For large or complex pieces you can cut the waste so you aren't trying to roll back large sections. If the sticky part of the waste hits the vinyl, they can be hard to separate without hurting the mask. If this does happen, be prepared to recut the pattern rather than make yourself miserable trying to separate the vinyl without distorting it. Since this is going on a curved glass, I cut the vinyl fairly close to the letters to minimize wrinkles. The third photo shows the amount of detail you can get with the cutter and the etching process.
Step 6: Lift the Mask
I use a clear, medium tack transfer tape. It should be sticky enough to lift the mask from the backing but able to release it when you have the mask on the glass. I find it easier to put the tape down on the table sticky side up and put the mask on top of it, vinyl side down. Then I rub it down and carefully peel back the backing so that it is folded back on itself. Go slowly and if a part stays on the backing, rub it back down harder and peel slower. If you don't want to buy transfer tape, clear shelving protection film can be used. If it is too sticky to release the vinyl (next step), you can press it against a T shirt once or twice to reduce its stickiness.
Step 7: Attach the Mask to the Glass
Very carefully, pick the position for the mask, being sure it is level. Allow the center to stick to the glass first and then slowly work out to the ends. Rub it down hard as you go. If you have a wrinkle or bubble that reaches a border to be etched, it must be fixed or the etchant will run under it. If you can't get the wrinkle out, put it up and throw the mask out and try with a new one. If the glass has walls that curve from top to bottom, cut the mask as tightly as possible to the image and work slowly.
On the glass on the right, the wrinkle to the right of 'of' was not a problem because it didn't reach the edge of the mask. The one on the left was a problem. I was able to rub it down hard and have it stay down for about 8 minutes. I did that right before etching and rinsed as soon as it reached the 'o'. I should have removed the mask and tried again, maybe with the three lines put on separating to minimize the stretching or found a straighter glass.
Step 8: Add Additional Masking
Once the mask is in place, remove the transfer tape, rub the mask down hard without touching the etching area with your fingers and then tape around the mask to add a buffer in case of drips. Either masking tape or scrap vinyl will work well as long as you overlap a bit and leave no gaps. I find that pressing some of the backing material against the vinyl is a good way to avoid accidentally touching the glass and leaving fingerprints.
Step 9: Apply the Etchant
Apply the etchant with an acid brush or a popsicle stick. Be sure to work it into the corners and coat all areas. It does not need to be very thick. Every minute or two I swish each area to mix up the etchant and discourage blotching. Theoretically, you only need to etch for a minute or so but I do 10 minutes (you can't overetch if your mask is good) with at least 4 dabbings during that time.
Step 10: Rinse and Remove the Mask
If you want the mask to stay on (for coloring), rinse carefully in cold water. Be sure to get all the etchant off. If you want the mask off, rinse in hot water. Be sure to run plenty of water down the drain to dilute the etchant. Although many people seem to be rinsing the etchant with bare hands, I have been warned that the chemical can be absorbed through the skin so I use a glove on my rinsing hand now.
Step 11: Coloring the Glass
When I want to color glass, I use Rub 'N Buff. It is pretty inconsistent so test it on some scrap glass. The evenness and quality of color vary from tube to tube. I use an old white sock, put a dab on the sock and rub it into the etched area with a circular motion. If there is no mask, it is OK to get it on the unetched surface but after 10 seconds of rubbing, it should be wiped off with a clean section of the sock. I wouldn't put a colored piece in the dishwasher but they can be hand washed. For opaque highlights, you can use enamel paints. For decorative pieces that will not be washed, permanent markers can be used. Always check a coloring technique on some scrap glass first. I have had good luck coloring detail but a hard time getting an even color on larger areas.
You can see the test glasses that I have. I added the different colors to randomly etched areas and labeled them with a Sharpie for reference.
Step 12: All Finished!
So, that is it. You can make some great, personalized presents - cups and glasses, suncatchers, Christmas ornaments, pencil holders and picture frames (with a sentiment etched into the glass in a corner). Have fun!