Fused Bottle Glass Fritballs

bottle glass frit balls

Cobalt Blue bottle glass frit balls.

Lately I’ve become enamored of working with frit balls. I had no idea how fun and addictive these things are! Maybe because they look like unnaturally colored caviar or tiny marbles, who knows, but they are pretty cool. First though, you have to make them.

Making the Frit

The first step, obviously, is to make the frit. There are several ways to make frit, the most obvious one is to smash broken glass into even smaller pieces. This is certainly an acceptable way to do it. There are several frit making contraptions/pistons available on the market. They all make relatively small portions of frit at a time, which is fine. Let’s look at some other ways of making frit:


Heating bottle parts and then quenching them in cold water is a quick way to make a lot of frit and of keeping it relatively clean and dust free. Guest blogger Beverly Frey wrote a comprehensive tutorial about the various temperatures and resulting frit sizes for us last year. There are some safety measures that must be taken as the heat and potential splashing can be dangerous. Use common sense and work with a partner. Bottle Glass Frit Making


If you have a bit of mechanical prowess you can make a mechanical frit maker using a garbage can and a garbage disposal. The resulting contraption makes vast amounts of frit in a very short time. One of the advantages is a very uniform range of frit sizes.

disposal Frit maker

Frit making machine, affectionately named Chewy

Unfortunately, it is also quite dusty and the resulting frit is laced with metal shavings that have to be removed with a strong magnet after grinding. The black tube on the top of the lid connects to a shopvac with a water trap to keep down dust. It’s always important to also wear a respirator when using Chewy, as well as hearing protection, and safety glasses (it’s an exciting process!) Here is a quick photo of the spectrum of sizes produced with this method:

Sample of frit size spectrum from Chewy

Sample of frit size spectrum from Chewy


For smaller (less than 5 lbs at a time) batches of frit, I use a tyvek sheet and my handy smasher. This device was made for me by a local welder, it’s essentially a solid steel block welded onto a pipe. The pipe is long enough I can stand straight, while lifting and dropping the smasher straight down onto the glass. This helps avoid any repetitive impact on my wrists and hands. Simply fold the glass into the folded tyvek sheet and smash. The resulting frit is of quite varied sizes, the larger pieces may need to be filtered out and resmashed.

Filtering the frit

Most frit making processes result in multiple sizes of frit in the same batch. It’s often a good idea to filter the frit into uniform sizes to make it easier to use in multiple projects. Depending on how much frit you are making, you may want to use a set of frit sifters, or, if you are making large volume or concerned about more accurate size separation, consider cobalt blue frit chunks

Cobalt bottle glass frit before firing

I spread the frit pretty thickly on the shelf. If you are concerned with multiple frit pieces fusing together and making globs, you may want to spend a little extra time spreading the frit out more evenly.

Firing schedule for Bottle Glass Frit Balls:

500/hr to 500 h 10 (this is to evenly heat the kiln shelf)

500/hr to 1535 h 3


If your frit balls don’t bead up to be round on the top, you may need to go hotter. If the frit balls are all heavily devitrified, you may need to lower the top temperature.

Cobalt Blue Frit Balls

Cobalt Blue Frit Balls

After the kiln has cooled to room temperature, use a soft paintbrush to sweep the frit balls into a container. I use a 3″ x 5″ card to scoop them up. The sweeping will cause some dust to rise up from the kiln wash on the shelf, so wear a mask for this part too!

Washing the Frit Balls

After fusing and sweeping, your frit balls are probably going to be a bit dusty again. Wash them using the same method as washing frit pieces and store in a clean container until ready to fuse into a new and amazing project.

I’ve found if I keep some clean frit pieces on hand at all times it’s an easy thing to sprinkle a few pieces on the kiln shelf around regular fusing projects. This helps fill empty space in the kiln, and the quantity of frit balls adds up quickly!