Glass fusing is an exciting art form that allows you to create beautiful works by combining compatible glass pieces in a kiln. When heated to high temperatures ranging from 1400-1500°F, the edges of the glass pieces begin to soften and fuse into one solid piece. You can stack, layer, and arrange glass pieces with glass fusing to make dazzling designs.
While glass fusing may seem intimidating at first, it is an accessible art form for both beginners and experts when you have the right knowledge and tools. The key is using the proper glass material, kiln, and safety equipment. With some practice fusing glass in a kiln, you can make stunning jewelry, plates, coasters, bowls, wall hangings, and more.
Selecting the Right Glass Material
The first step in fusing glass is choosing the correct type of glass. Using incompatible glass types with different COEs (coefficients of expansion) can lead to cracking and breakage during fusing. It’s crucial to select an art glass formulated specifically for fusing, often called fusible glass.
Standard float or window glass has a different COE than most fusible glasses and is not recommended. Test compatibility between glasses by fusing two small pieces and looking for cracks after cooling. High-quality fusible glass is available from art glass suppliers in a wealth of textures and colors to suit your projects.
1/4 inch (6mm) thick fusible glass offers the best properties for fusing. Going thinner than 3mm can lead to shrinkage and loss of shape during firing. Exceeding 9mm thickness causes the glass to push outwards and lose its form. Between 6-9 mm gives you the best shape retention.
In addition to solid sheets, you can incorporate frits, stringers, and dichroic glass into your designs for more diversity. To prevent spotting or fogginess in the final piece, thoroughly clean all glass before firing with a specialized glass cleaner.
Choosing the Right Kiln
Having the proper kiln is mandatory for fusing success. Look for a kiln specifically designed for glass fusing, which evenly heats the glass from the top down. This allows even heating and prevents cracking. The chamber is smaller than a ceramic kiln, which aids in temperature uniformity.
Consider the size of projects you want to create, and choose a kiln that offers enough interior space to accommodate them with room to spare. Larger production projects may need a more spacious model. Ensure the kiln offers excellent temperature accuracy and control up to at least 1500°F.
While you can fuse in a ceramic kiln, achieving uniform heating will be more challenging. Extra care must be taken with firing schedules and glass placement. Investing in a true glass fusing kiln gives you the best results with fewer frustrations.
Preparing Your Workspace and Safety Gear
When fusing glass, safety should always come first. Have a clean, organized workspace free of clutter, and always wear protective gear. Required safety equipment includes:
- Kiln gloves – These will prevent burns when handling hot glass.
- Safety glasses – Protect your eyes from glass shards and dust.
- Dust mask – Block dangerous particulate matter from entering your lungs.
- Proper Clothing – Wear natural fibers like cotton/denim that won’t melt if exposed to heat.
Arrange your tools in an easily accessible area, so you have what you need at your fingertips. Necessary supplies include a glass cutter, running pliers, grozing pliers, breaking pliers, and a specialty glass cleaner.
Cutting Your Glass
You can begin cutting glass to your desired shapes and sizes with your safety gear on. Start using your glass cutter to score the surface where you want the piece to break. Finding the right pressure takes practice – too light, and the glass may chip, too heavy, causing uneven breaks.
Once scored, use running pliers on both sides of the line to apply pressure and evenly “run” the break along the score. You can cut curves or straight lines this way. For removing unwanted edges, grozing pliers come in handy to chip off pieces precisely.
Cut an assortment of geometric or free-form shapes to stack and lay out your design. Remember, you’ll be limited to what you can fuse in a single layer. Smaller pieces make positioning and alignment easier.
Designing Your Fused Glass Piece
One of the exciting challenges of glass fusing is planning the layout of your piece. While you can fuse items flat for a smooth surface, incorporating multiple layers and levels opens up many possibilities. Brainstorm creative ways to arrange your glass bits into a cohesive design.
Start by cutting a base piece slightly larger than your finished size. Next, lay out the additional shapes in the desired pattern on top of the base. You can also create channels by stacking glass strips or frit in between pieces to add grooves and texture.
Planning your design well is important, as once fused, the glass will conform to its shape before firing. Use a small amount of glue to hold pieces in place for transport to the kiln temporarily.
Loading the Kiln for Fusing
Once your design is planned, it’s time to load up the kiln! First, ensure your kiln shelf is coated with primer. Place the glass directly on the shelf or fiber paper. Position the shelf higher in the kiln, leaving ample space below. This aids in even heating.
Set your project in the kiln, keeping a 1⁄4 inch margin from the sides for expansion. Make sure shapes are aligned properly and supported underneath to prevent slumping when the glass softens. Allow at least 1 inch between separate projects and 2 inches from kiln walls.
Double-check that glass pieces are sparkling clean before firing. Any dust or oils will get trapped on the surface. It’s also critical that all materials are completely dry before lighting up the kiln.
Choosing a Fusing Schedule
Your kiln’s digital programmer gives you total control over the fusing schedule. Several aspects can be customized:
- Ramp Rate – The heating/cooling rate in degrees per hour
- Temperature – Target temp to hold at
- Hold Time – How long temperature is maintained
Key segments include initial heating, process, annealing, and cooling. Go slowly up to 1000°F, then ramp faster to your fusing temperature – usually 1480°F. Hold to fuse fully for 15-20 minutes, then slowly anneal to 1000°F. Reference your kiln manual for specifics.
For tack fuses, aim for 1350-1370°F. Full fusing requires 1460-1470°F. The longer the glass remains at temperature, the more dense it becomes. Test fire on scrap glass to hone in on the ideal schedule. Taking detailed notes is invaluable.
Removing Your Piece from the Kiln
Patience is mandatory when it comes to unloading your project. Never open the door until the kiln reads below 100°F. Quick temperature changes will lead to cracking or shattering inside the kiln. Safety gear should still be worn when removing shelves.
Use kiln gloves to slide out the shelf carefully. Inspect your piece thoroughly and look for any stress cracks which indicate incompatible glass types may have been used. If all looks well, you can slump or move on to coldworking to refine the edges and surface.
Slumping Your Fused Glass
The slumping process comes next for adding shape and dimension to your fused glass. Place your solid fused piece over or inside a mold that matches the contour you wish to create. Items like bowls, plates, and other vessels work well.
Fire the mold with glass inside to around 1225°F to allow the glass to soften and conform to the mold beneath. The hold time at this temperature is much shorter than fusing, usually 5-10 minutes. Accurately programmed slumping transforms flat fused pieces into amazing functional and decorative glass objects.
Achieving Success With Glass Fusing
Like any specialized art form, mastering the nuances of glass fusing takes diligent practice and patience. Arm yourself with the proper glass material, tools, safety equipment, and kiln for the best results. Allow time to hone your glass-cutting skills and experiment with firing schedules.
Start slowly with basic projects, and you’ll be amazed at what you can create once you understand the foundations and the endless possibilities for intricate and dazzling kiln-formed glass art. Let your imagination run wild, and enjoy watching your visions come to life inside the kiln!
FAQ
What temperature should I fire dichroic glass?
Dichroic glass requires slightly lower fusing temperatures than standard art glass, usually in the 1350-1400°F range. Follow the manufacturer’s instructions for the dichroic material you use for best results. A medium fusing schedule is recommended to avoid losing the special dichroic effect.
Can I fuse stained glass pieces?
Traditional leaded stained glass is not compatible with art glass for fusing purposes. The COE and viscosity are poorly matched. Use glass specifically formulated for fusing rather than repurposing salvaged stained glass material for best results.
Is it possible to fuse glass using a microwave kiln?
Microwave glass kilns are unsuitable for glass fusing, as they do not allow the customized programming and controlled ramp rates to properly fuse glass without cracking. The fast heating of a microwave kiln makes glass fusing very challenging.
Can I fuse different thicknesses of glass?
It’s best to use a glass of uniform thickness when fusing, ideally 1/4″ thick. Combining thin and thick glass pieces in one project can lead to uneven melting, distortion, and breakage during firing. Thinner materials fuse faster and flow more readily than thick ones.
How do I know if my kiln has reached the target temperature for fusing?
The best way to ensure your kiln reaches the high temperatures needed for fusing is to calibrate it professionally yearly. Also, utilize witness cones placed inside the kiln during test firings. Comparing melted cone shapes will verify if kiln temperatures match the controller readout.
Conclusion
Glass fusing is an immensely gratifying art form that allows creators to produce stunning works by joining glass together through the intense heat of a kiln. While the process requires specialized equipment and safety precautions, the basics can be learned by anyone interested in glass art.
Beginners should start slowly with small projects using high-quality fusible glass. As experience is gained, more elaborate multi-layered and 3D pieces can be tackled. Patience and persistence will be rewarded with skills to transform molten glass into dazzling plates, jewelry, bowls, mirrors, wall hangings, and more.
The joy of kiln-formed glass is seeing your creative vision emerge from raw materials into a fused, slumped, sculpted masterpiece.