Alcohol Ink on Glass Sealant Test

One of the most common questions I receive about alcohol ink is: "How do I seal that" or "What should I seal that with?" Even when I see other inkers on Instagram or Pinterest, I often have the same question, "I wonder what they sealed that with?" Sealing glass alcohol ink projects is even trickier since the end product needs to remain glossy and translucent. I've often just skipped sealing the craft projects because I was worried the sealant would either ruin the ink or the glossy finish. But if you want your alcohol ink projects to last, it's usually a good idea to seal them.

So, I dug out all of my sealants (well, I do have a couple more versions of regular spreadable mod podge, but I picked the one I thought would work the best and most easily on glass). I ended up with 8 different products. I'm sure there are lots more similar products available out there, but these 8 are definitely a good start. Since I wanted to test the results on glass, I needed to find 8 of the same glass items I could ink. These memory keeper slides seemed like a good choice. I couldn't find them for sale anymore online, but they seem similar to scientific slides in thickness and weight; these just happened to be cut square for scrap booking and crafting.

I selected 4 colors of ink that I thought would have good saturation on glass and dripped, spread with a small paint brush to make sure the whole slide was mostly covered, and then flamed them to set and spread the ink.

I made a point to try and get all 4 colors on all 8 of the slides, but the pink was covered a bit by some of the other colors on a couple of the slides. These also got a fair bit of ink on their backs as I was inking them, so after they dried to the touch, I wiped the back of the glass off with some rubbing alcohol on a paper towel.

I set them aside to dry overnight, but it has been off and on rainy here, so it ended up being two days. It's always a good idea to let alcohol ink dry for several hours before applying any kind of sealer--especially the kind that get brushed on (like mod podge). If they are completely dry, there's less chance of the ink reacting with the sealer.

So, they dried all the way and the weather 2 days later was gorgeous. 72 and breezy! So I selected a paper plate for each slide and its sealer. I painted on a generous coat of the two paint on versions and set them aside. Then I sprayed the rest. I shook each can briefly and sprayed a couple generous passes onto each slide. I wanted to make sure that if the spray was going to react with the ink, that it would. I left them all to dry on the patio table for 20 minutes and sprayed on (and painted on) a second coat of everything. Then I brought them inside to dry overnight.

After they dried, I did 3 tests to determine the quality of the finish: water, alcohol, and fire. I ran the slide under a stream of water and rubbed it with my finger to check color fastness and reaction with the sealer. Then I spritzed it with enough rubbing alcohol to check to see if the surface was completely covered and if the sealant reacted. Then, after they had all dried and evaporated their rubbing alcohol (I waited several hours), I came back and ran a lighter flame over each slide to check for heat changes and flammability. 

Up first is the Glossy Mod Podge--a classic choice for sealing. It's water based, so it doesn't react much with the ink (except maybe from the friction of brushing it on). It goes on cloudy and dries clear and cleans up with water. It's widely available at pretty much any store that sells craft supplies. However, on glass, it leaves distinct brush strokes which can look kind of sloppy, and the finish will dissolve just a bit with water. I have used Mod Podge on a ton of projects, and the water reaction after dried is pretty minimal, but it can make the surface slick and prolonged contact with water can make the Mod Podge turn gummy. Also, surprisingly, the finish clouded when sprayed with rubbing alcohol. It did not react to the flame at all. So I'd say Mod Podge would only be a good idea on specific types of projects that you don't mind the brush strokes, and it's not going to come into contact with liquids. I have used Mod Podge on several opaque projects without issues and even used the dishwasher safe version of Mod Podge on a plate. That version of Mod Podge is much more water resistant, but also takes a month to cure.

Rating: D (Not the best for glass, but easy to use and clean up and available everywhere)

This product is a fairly new one for me. It's DecoArt/Americana's Triple Thick Gloss Glaze. I have used it for a couple of projects so far with sort of mixed results, but this is my first attempt using it on glass. It suffered from the same brush stroke issues as the Mod Podge, but it also stripped quite a lot of ink off of the slide in the process. The final finish was impervious to water, alcohol and fire, but it doesn't much matter since it's reactive with the ink and strips off so much of your hard work.

Rating: F--Not recommend for Alcohol Ink on Glass

Now we can move on to the various spray-on sealers. First up is Mod Podge Gloss Acrylic Sealer. I have used the Matte Acrylic Sealer from Mod Podge for several projects (up next), but I hadn't used the Glossy sealer. I knew that Glossy would have a better finish on glass, so I picked some up to try. I was surprised when I sprayed it on that it reacted with the alcohol ink a fair bit. The finish, once dried, was a bit speckled. It passed the water test with no issues, but was the only product that failed the rubbing alcohol test by bleeding ink onto my fingers as I swiped it. It apparently did not get a complete seal on the ink. It survived the fire test with no changes.

Rating F--Not recommend for Alcohol Ink on Glass

After the disappointing performance of the glossy spray, I was expecting the Mod Podge Matte Acrylic Sealer to tank the tests too, but it didn't. The finish is cloudy and matte, but it survived all of the tests beautifully. I have used this product several times on opaque surfaces with good results.

Rating: B (because most of the time you're not looking to make your glass projects look fuzzy and cloudy, but if you are, this stuff works great)

Next we have a series of Krylon sprays to test. The first is Krylon Covermaxx Crystal Clear Acrylic Gloss. I think I bought this one at the hardware store in the spray paint section.  It reacted with the alcohol ink when sprayed on, leaving a puddle of hot pink ink on the plate. It also dried to a speckled finish. It did pass the rest of the tests, but the initial spray ruined its score. I did use this spray very thinly on a ceramic tile project once in the past and managed minimal reaction with the ink, but the sealer actually started yellowing and flaking off as it aged.

Rating: F--Not recommended for alcohol ink on glass.

I was starting to get a bit discouraged by the results, but then, trusty old Kamar Varnish came along. This stuff is usually available in the art supply section of stores, and not in with the hardware store spray paint. This stuff sprays on pretty much the same as the acrylic sealers, but has a slightly stronger smell--so be sure to use in a well-ventilated area (outside would be best). But, it has pretty much zero reaction with the alcohol ink. The finish on glass was also surprising clear. It survived the water test with no issues and didn't bleed when sprayed with rubbing alcohol; however, the finish did become cloudy as it dried. It had no changes or reactions from fire. 

Rating: B (reaction to rubbing alcohol means it may need to be paired with another sealer to get a durable finish)

Next up is Krylon's Triple Thick Crystal Clear Glaze. This stuff is also usually in the art supply or craft section of a store as opposed to being shelved with the spray paint. It provided a pretty decent finish, although it goes on generously enough that I had a little pool underneath (hence the cloudy spot on the photo), so I need to spray lighter coats for future projects. This product passed the water, rubbing alcohol, and flame tests with no changes.

Rating: A (as long as you spray lightly)

This last one is a bit of a wild card. I bought a can of Rustoleum Engine Enamel for the specific purpose of using it to seal candle holders and ceramic tiles for use as hot plates or trivets. I was expecting it to react with the ink. I was also not expecting all of the rest of the products to test fine to a flame. I figured at least one or two of them would turn yellow or get sooty--but they all seemed to do fine. That being said, I was kind of amazed by how well this stuff worked. It had almost no reaction to the ink and had a beautifully smooth shiny finish. It aced all of the tests and is officially rated for up to 500 degrees, so should be perfect to use for the projects that you might be worried about getting a bit on the hot side.

Rating: A

So, the final tally, I do not recommend the DecoArt/American Triple Thick Gloss Glaze, the Mod Podge Clear Acrylic Sealer, or the Krylon Covermaxx Acrylic Spray for use with alcohol ink on glass. 

I do recommend Kamar Varnish as a setting spray and the Krylon Triple Thick Crystal Clear Glaze and the Engine Enamel. And if you're looking for a slightly frosted matte finish, the Mod Podge Matte Acrylic Spray works just fine.

Note that your results may vary. There are a lot of variables involved when using spray sealers (like temperatures and humidity levels when sprayed etc...). Also, these ratings are ONLY for alcohol ink on glass. The products that failed this particular test, may (and probably do) work well for other media. Also, I only used Ranger Alcohol Inks in this test just to keep things simple, so the sealers may behave differently with different brands of ink.

What did I miss? Do you have a sealer that you use with alcohol ink that I need to try out? Let me know in the comments!