Tips for Tack Fusing

tact using is an effective method for creating textured works in kiln form class in tact fusing glass is fired within a range that creates enough heat work for the material to fuse while maintaining the desired amount of form and texture tack fusing often results in pieces with varying thicknesses this raises technical issues in this lesson you'll learn the effects of firing two different tack views temperatures will also cover firing schedule considerations to avoid thermal shock and promote effective annealing finally we'll follow a project through tack views and slump firings when designing tach fused works it's helpful to know what to expect when firing to different temperatures and the effects of cumulative heat work tack fuse process temperatures generally range from 1250 to 1450 degrees Fahrenheit constructing attack views with two base sheets in a single firing results in flat bubbles where the layers have not fully fused if this isn't what you want consider taking a multiple firing approach full fuse two layers of 3 millimeter sheet glass to make a base and follow with a lower tax firing let's look at the effects of firing this test piece composed on a pre fused six millimeter base sheet with an assortment of sheet and accessory glasses fired to the low end of the process temperature range TAC fused elements have sintered or heated just enough to adhere while maintaining much of their original form fired to the high end the elements are more fully fused to the base and have softer edges for greater variation in effects use a sequence of multiple attack use firings moving from higher to lower process temperatures in this piece sheet glass design elements were tacked fused to 1425 then frit was added before an additional firing to 1325 note that light applications of fine glass such as powder and fine line stringer will soften and flattened at the hotter end of this temperature range courser fritz and larger materials will remain in higher relief reactions such as in this copper and sulfur bearing combination will be less developed or not present at all in low temperature tack views firings this is especially true when compared to firing to a full fuse note that strikers may not fully develop their target color at attacked using temperature especially at the lower end of the range here we use transparent orange it's important to keep in mind that heat work is cumulative this means that the more times a glass is fired the more likely it is to change in some way and note that each firing can affect any new materials applied as well as the materials that have already been fired there are endless effects to explore firing in this temperature range considering different techniques forms and combinations of material to prevent thermal shock and ensure proper annealing pieces with uneven thicknesses require specific modifications to the firing schedule let's walk through the decision-making process for firing this light diffuser we'll start by firing two layers of opaline to a full fuse next we'll add six millimeter clear sheet glass design elements because the bass is a solid piece we've slowed the initial rate of heat to a conservative 300 degrees per hour the goal is to avoid thermal shock which can occur when firing too rapidly again since the bass is a solid piece there's no need for a hold at 12:25 to squeeze air from between the layers instead we'll choose a short hold at 1,000 degrees this brings the piece pass where it could thermal shock and unifies the temperature within the body of glass the second segment ramps up to the process temperature in this case 1425 with a 10-minute hold the third segment encompasses the anneal hold at 900 degrees we'll determine the duration by the thickness of the project using the annealing chart for thick slabs will select an anneal soak time for a piece that is twice the thickness of the thickest area of this piece this longer hold promotes a uniform temperature throughout which is necessary for proper annealing calculate this by adding up the thickness of the components for this project the thickest area is 12 millimeters so we'll double that and follow the chart for a thickness of 24 millimeters use the annealing chart to determine the rest of the cycle slower cooling allows the thinner areas to cool at the same rate as the thicker areas this minimizes annealing strain and lowers the likelihood of thermal shock next we'll add more design elements and then fired to a lower temperature to create a light diffusing effect once again we'll use the annealing chart for thick slabs as a guide for reheating the tack fused piece to determine the initial rate of heat refer back to the final rate of cooling for twice the thickness of the thickest area in this case the rate is 162 degrees per hour to 1000 with a 20 minute hold then 600 degrees per hour to a process temperature of 1335 with a hold for 10 minutes we do this to approximate the same effect as firing at a faster rate to 1350 this is because the insulating materials of the kiln will have more time to absorb heat due to this slower rate this will cause slower cooling from process temperature resulting in more cumulative heat work as the thickest area has not changed will again follow the annealing chart for 24 millimetres to anneal and cool the piece now we're ready to slump the piece we'll follow the guidelines we've established in the early firings using a process temperature of 1180 with a 5-minute hold in the finished piece tacked fused elements interact with both reflected and transmitted light - creating textures in the kiln tack fuse techniques can also introduce lensing and other optical effects tack fusing makes a variety of textured works possible a solid understanding of the effects of cumulative heat work and strategies for firing effectively can help you achieve your artistic vision you

Channel: Bullseye Glass Co.

Views: 24,590

Keywords: Kiln Glass, Art Glass, Fused Glass, Education, Educational, Classes, How To, Glass, Fusing, Glass Fusing, Warm Glass, Art, Online Education, Craft, Crafts, Tutorial, Making, DIY

Id: 5-iFXp2-CyQ

Length: 7min 52sec (472 seconds)

Published: Fri Aug 23 2019