Your Glass Cleaning Guide: How to Fix & Prevent Devitrivication

Proper glass cleaning takes more than a bottle of Windex when it comes to your fused glass projects (in fact, Windex is a no-no).

Buildup from fingerprints, residues, soaps, dust, fibers, and salts can have a bigger impact on the outcome of your fusing projects than you’d think. One wrong turn of the dial on your kiln, and these residual contaminants can come back to haunt you in the form of devitrification, also known as devit.

What is Devitrification?

Devitrification, or the process of undoing the “glass-ness” of your project, is a very real threat to your kiln work. It happens when contaminants on the surface of your glass cause a reaction in the kiln that crystallizes the surface of your glass, giving it a dull, streaked, wrinkled appearance.

Your glass may even crack as a result of the crystalline formations, so we’ll show you how to prevent them, as well as how to deal with them once the damage is done.

How to Avoid the Perils of Devit

The best way to avoid a devit problem is cleaning your glass before firing. You want to make sure you take a look at your glass from multiple angles to ensure a streak-free and lint-free shine.

To achieve this, you’ll need lint-free towels, a proper glass cleaner, and perhaps a razor and isopropyl alcohol for stickers. Bullseye Glass recommends using a mixture of vinegar and denatured alcohol, as you’ll see in the video below.

Glass Cleaning from Bullseye Glass on Vimeo.

We also recommend using devitrification spray to ensure maximum devit-free shine on your fused glass products.

Common Glass Cleaning Pitfalls

Here are some common devit-causing mistakes you can easily avoid:

• Don’t use commercial glass cleaners like Windex, they contain polymers and residues that leave behind streaks after firing (so much for that streak-free shine)!
• Avoid using disposable latex gloves unless you’re sure they aren’t treated with powders
• Mind your edges! Getting fibers trapped on edges during the cleaning process can upset the look of your finished piece. Grinding them down a bit helps avoid catching.
• Avoid using fabric softener on your load of cleaning towels

Devit Troubleshooting

Devit happens. Not everyone’s perfect, but luckily you can get your fused glass back on track with some quick sandblasting or grinding. You can browse our selection of cold working tools online here.

The extent to which you sandblast will naturally depend on the severity of your devit, which you’ll ultimately want to grind down. After doing so, just fire polish your piece by placing it back in your kiln at the recommended temperature for your desired effect. The brilliance of your glass will return in no time.

If you aren’t too keen on grinding your finished piece, don’t despair. You might just get away with it by coating a thin layer of clear glass powder over the top of your glass and firing it for a few more minutes. Note that the devit may return if you re-fire after this!

Still having trouble with your glass project?
Browse our devitrification chemicals online, or find an upcoming class that demonstrates fusing techniques.

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