What can I expect from Bullseye rods?
Bullseye rods are an accessory glass that can be added to kilnforming projects to create a variety of unique design elements.
Compatibility: Bullseye Compatible rod styles are factory tested to the same standards as other Bullseye Compatible materials for kilnforming.
Color: Hue, saturation and opacity are evaluated.
Shape: Diameter, roundness and straightness/warp are evaluated.
Clarity: Rods must fall within an acceptable range for bubbles, stones and surface qualities.
Overall performance: Color striking and workability are evaluated.
Bullseye rods are also graded:
T grade rods are formulated for flameworking and not recommended for kilnforming. They include Lustres, Opaques, and other styles.
F grade rods are rated for both flameworking and kilnforming. They are part of the Bullseye Compatible product line.Both F and T grades may be combined reliably in the torch.
Both F and T grades may be combined reliably in the torch.
Kilnforming with F grade rods:
The material characteristics of F grade rods relate closely to the Bullseye sheet glass palette, with some noteworthy differences, generally driven by the rod-forming process and the nature of the form itself. Comparisons to 3mm sheet glass are drawn here.
Transparents: It's important to consider how color saturation relates to volume and thickness of form. The diameter of a rod is greater than the thickness of standard 3mm sheet and displays more saturated color. Many styles are highly saturated and will reveal lighter coloration if used in small amounts, displaced and thinned through kilnforming methods, or ultimately coldworked to remove material. Conversely, the 001800 series has subtle coloration and much greater transparency, which is suitable for working thicker or as visual representation of negative space in thinner works. For medium color saturation, the 001500 series (currently unique to rod) has less color saturation and more transparency than its 001400 counterpart. As a general guideline, color saturation decreases as the style number increases. Striking transparent pinks and purples likely contain a linear streaked design along the length of the rod, which may also be visible if fired on end. Linear streaking is most prevalent in the following glasses: 001215, 001232, 001305, 001311 and 001342. Hue and saturation may also differ slightly when compared to sheet glass; a wider range is accepted due to changes that occur in the forming process.
Opalescents: Expect more variation in opalescent rods when compared to sheet glass, with several styles taking on both greater opacity and lighter coloration. This visible shift occurs in sulfur glasses during the forming process and remains stable through kilnforming. Similar comparisons in color and opacity could also be drawn between sheet glass and stringer. (See www.bullseyeglass.com/torchtips for more information about sulfur content.) When viewed on end, opalescent rods may exhibit a small dark spot—a core that runs the length of the rod. Whether it is a darker version of the rod color or transparent in nature, it generally remains stable through firings and can be used as a design element. This too, is a result of the forming process.