6 Things That Make Glacial Art Glass Murrine the Best Choice for Kilnworkers

Glacial Art Glass Murrine are not your average murrine. We'll give you 6 reasons:

1. Bullseye Glass
2. Slice Quality (Don't underestimate this one!)
3. Compatibility Testing
4. Design Variety
5. More Choice Control
6. Dependable Repeatability

1. Bullseye Glass

We make our murrine with only Bullseye fusible grade glass, one of the most common glasses used for kiln work. Artists using this glass will be familiar with the color palette and the technical aspects of working with each of those colors. Bullseye Glass can often be used with any COE 90 glass, but this needs to be tested on a case by case basis to be sure it will work in a specific project.

2. Slice Quality

(For those who prefer to order uncut cane, we anneal all murrine cane to help you get better cutting results. Read on to learn what slice characteristics you will want to aim for.)

Slicing is one of the most labor intensive parts of the murrine making process. It’s normal to cut as many corners as possible to reduce time, but this can create some serious drawbacks, especially for those who plan to use murrine in kiln work.

We cut our murrine carefully by hand one slice at a time, and then sort them – one at a time. Somewhere between 20 and 30% of the murrine cane and slices are removed because they don’t reach our standards. Here are the qualities that make a murrine good for kiln work:

Level

Gravity forms glass in the fusing process. A slice needs to be able to sit flat on at least one side, so that the design is perpendicular to the force of gravity. This ensures that the murrini settles straight downward while fusing, instead of slumping over toward a side, warping the design of the murrini and the overall shape of its footprint on the surrounding glass. It takes more care to get level slices, especially as the diameter of the cane increases. The added time is significant when one considers the overall amount of labor that cutting takes, but it's important to take it.

Thinness

The thinner a murrine, the less chance gravity has of distorting the murrine. This is especially important if the design has transparent or translucent colors, because even if the murrine settles straight down, it tends to squish outwards to different degrees from top to bottom. This creates overlap within the murrine between the top and bottom. Less height, or thickness, means less overlap, and less obscuring the design. However, murrini makers realize that cutting half the thickness means they have to spend more than twice as much time cutting – the same amount of murrine is cut twice as many times, and thinner slices are much more difficult to cut, resulting in added time, and more lost material. For these reasons, a lot of murrini slices are cut too thick for optimal kilnworking, often thicker than the diameter of the cane. We think half the diameter or thinner is best.

There is another advantage to thinner slices – if the murrini is sold by weight, you get more for your money.

Whole pieces showing the full design

This should be an obvious step to take, but some murrini makers don’t sort out all the chips and not-quite-whole pieces before packaging. This means an unspecified amount of the product is practically unusable. We want our customers to know they are getting all that they're paying for.

3. Compatibility Testing

Bullseye has been manufacturing glass for kiln forming for probably longer than any other company. They were the first to do extensive testing for compatibility, and they still do the most to make sure that their glass is dependable in this respect. This is important for kilnworkers because flatter (vs 3D round work), thicker, or just larger work can require much tighter compatibility tolerances than some other types of work. Kilnworkers also tend to fire components several times before a piece is finished – added heatwork that can change the chemistry of some glasses.

Bullseye guarantees that glass they sell as “Fusible” has been tested compatible for up to three firings to 1500 degrees Fahrenheit, each with a soak time of 15 minutes at that temperature. They test every run of glass in the same way, and they publish their testing methods. This means that we can test with the same process, and offer you a product that is virtually just as compatible as the glass that it is made from. Also, we have designed a process that minimizes the heatwork necessary to make murrine, while most makers of large quantities of murrini use a process that is extreme by comparison, taking the glass to temperatures far beyond those stipulated by Bullseye’s compatibility guarantee, and for far longer periods of time. This kind of heatwork can be the enemy of compatibility. But the bottom line is that Bullseye provides a testing method, and a standard to test for. We take advantage of this to make sure that our products are in line with what you would expect from Bullseye glass.

4. Design Variety

Our making process allows us to overcome many of the design limitations of other common processes, while still being able to sell the finished product at a great price.

5. More Choice Control

We sell single designs in small quantities so that you only buy what you like. It doesn’t make good economic sense for the customer to pay for a variety pack if they might not like some of the murrini in the mix.

6. Dependable Repeatability

High production artists, or just part-time hobbyists who know what they like, need to be able to use a product once, and then have the option of getting that exact product again sometime in the future. Although we make all our products carefully by hand, they are not “limited run” or accidental. We keep careful records and our process allows us to repeat a design nearly exactly, so months or years later you’ll still be able to get that one you like.