Have you ever wondered what lampworking looks like? This is an excellent video showing Kimberly Jae making a glass flower bead. http://www.youtube.com/watch?v=jMhe0gaALHE
The description on the video states: This demonstration / tutorial shows how one of my signature Funky Flower beads is created. I'm using Moretti (Effetre) glass in this demo on a Bobcat torch. Please visit my sites for more photos and online purchases.
www.kimberlyjae.com
Devitrification, a whitish scum that sometimes appears on the top surface of glass that has been fired in the kiln, occurs when glass remains at too high a temperature for too long. In most cases, devitrification is considered a nuisance, and glass artists will go to great length to prevent its formation.
To understand why devitrification forms, we must first understand the nature of glass at room temperature. Although a sheet of glass appears quite stable and unchanging, it's actually delicately balanced between two states of being. On the one hand, there is an equilibrium in the glass between its various constituents (sand, soda ash, limestone, etc.). On the other hand, a tension exists as these individual components (especially the sand) have a natural tendency to return to their original states.
When glass is heated, this equilibrium is interrupted. The particles of the glass are heated past their solid state and become increasingly liquid. So long as the glass is allowed to return to its solid form fairly quickly, the molecules are able to return to the normal configuration and the delicate balance is restored.
However, if glass remains at too high a temperature for too long, then the normal process of establishing equilibrium is interrupted and the molecules in the glass are prevented from regaining their delicate balance. Instead, the high temperature causes some of the elements in the glass to burn off. The glass crystallizes along the top surface, forming a crystal (called devitrite). A mild case of devitrification results in a dull whitish deposit on the glass, while more severe cases can cause the top surface to break down and even deteriorate completely.
How to make your own DEVIT SPRAY (Borax/water solution)
Purpose: To prevent or minimize devitrification
How to use: Spray or brush lightly on top surface of glass prior to slump firing.
Ingredients: 1 teaspoon borax to one cup water. Distilled water works best. Regular borax cleaning powder (such as the "20 Mule Team brand" in the US) works well. Precise measurement not required.
Safety precautions: Don't drink. Wash hands after using. Long term exposure to borax can be harmful.
How to make: Just mix the borax with the water. If you put the two ingredients in a small glass jar with a lid, then cover and shake, you'll be assured of a good mixture and have a place to store the solution, too. Label the jar. Shake again prior to each use.
Note: We use the Borax mixture when fusing in our own kilns at Harrach Stained Glass. Now, we do not use distilled water since that would mean an occasional trip to the grocery store which is out of the way. (We just use tap water.) What we like to do is apply the Borax mixture, by hand to certain glass pieces and with a paint brush on more delicate pieces that have many design elements. Originally we only sprayed the Borax mixture on the glass and tried fusing, but by doing it that way we ended up with permanent water marked stains on our blue and clear glass pieces. Later, on another project, we discovered that the spray bottle was clogged, probably with Borax particles from the bottom of our spray bottle. At that point we decided to pour a small amount of the homemade devit mixture onto the piece we were going to fire and then spread it by "hand" using just our fingers. This actually resulted in a perfect finish on the completed project with no devit and no fingerprints!
We have learned to never shake up or mix the Borax mixture that you have made right before applying. You will notice that the Borax and water seem to separate and the Borax will fall to the bottom of your container. We use the "top" water from our mixture to use as our devit "spray". Of course eventually your mixture will run low and you will need to make some more devit "spray". When you make it, shake it up well and then let it stand a while so that the heavier Borax particles will fall to the bottom of your container before you apply to your piece.
The Borax mixture has been good on difficult colors and fired at up to 1475 degrees with excellent results.
A pyrometer is a device that measures the temperature inside your kiln. This unit will assist you in improving your firing results, and in enabling you to monitor your process.
Reliable and continuous measurement is essential for efficient control of the glass fusing or slumping operation. Take notes as you proceed with your firings.
This unit is easy to read and monitor. The gauge is much like a thermometer in reading the temperature and is usually broken up into units of 50 degrees Fahrenheit.
Most kilns come with a stock equipped manually controlled infinite switch and a pyrometer with a thermocouple. The thermocouple is attached to one end of the unit with a cable. This is one continuous unit, to monitor your kiln.
While the infinite switch and meter are on the outside of your kiln to control and monitor the speed of your kiln heating up, the thermocouple is inside the kiln measuring the temperature.
These units work together to control the temperature of your kiln. This device will allow you to know the temperature of the air inside the kiln chamber throughout the complete firing progression. This unit is essential when you are firing glass. It will not allow you to know the temperature of your glass during the complete firing process, but the air inside the kiln.
There are two parts to this unit:
Thermocouple – A sensing probe that consists of two different metals that are welded together at the end. The thermocouple creates a small voltage when heated, which the controller translates to a temperature. It takes a hypersensitive instrument to read that small voltage. Because of this small voltage, the smallest amount of variation can make a deviation in the temperature reading. These are high temperature wires that are covered by a ceramic ring and placed inside the kiln.
Meter – This shows the temperature of the air inside the kiln and that is being registered on the thermocouple.
These units are different and can be off in temperature readings. Testing through different firings will enable you to know if the temperature of your particular unit is correct, or needs to be adjusted.
A thermocouple is the twisted soldered metal pieces on the end of a pyrometer.
It is a temperature sensor used to measure the heat of the air inside a kiln.
It is placed inside the kiln either through a pre-drilled hole for this purpose or through the peep hole.
This device consists of two different metals.
These are joined together at one end, and that end is placed inside the kiln.
When the connection of the two metals is heated a voltage is produced.
The voltage is measured and converted to a temperature reading.
This reading is then displayed on the readable face of the pyrometer.
For the best results on your reading, always leave about one inch of room around this twisted soldered metal.
Placing it closer to your shelf or glass can cause the temperature to read inaccurately.
Do not allow the wires touch any live heating element wire.
These devices can be used over a wide range of temperatures.
From the vast changes in temperature, this piece can be come brittle.
Try to avoid hitting it when inserting objects inside the kiln.
Although small, they are very inexpensive, hardy and consistent devices.
Time and high temperatures will cause these to wear over time.
If it appears corroded or crusty, it may be time to replace the piece.
They are also interchangeable and have standard connectors, which makes them simple and inexpensive to replace.
Changing this device when it has failed or become corroded can make a large difference in the accuracy of your firings.
This article accompanies the textbook The Real World of Chemistry 6th ed by Lois Fruen Kendall/Hunt Publishing ISBN 0-7872-9677-5
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Glassmaking originated in the Syro-Palestine area around the third millennium BC and was developed in Egypt in 1500 BC. The Phoenicians became the greatest glassmakers and exporters of the ancient world. This was because of the rich deposits of silica-based sand, which contained a substantial amount of lime, found along the coast of Lebanon (James 464 and Fleming 138).
Glass was rare. It was used in artistic pieces and given the same status as semi-precious stones by artisans. Beautiful bright red and yellow opaque glass and cobalt-blue glass ingots were used as beads for jewelry and in figurines and decorative vessels like the ones shown to the right.
Ancient people probably discovered the technique for making glass when firing faience. Faience is a type of ceramic pottery glazed with a sodium alkaline flux. If the glaze was mixed with the crushed silicon clay before firing, a glassy substance would have been produced in the body of the clay (Bowman 33).
Ancient glass vessels were produced in molds. The earliest datable example of molded glass was found in the tomb of Thutmose III’s three foreign wives. The tomb yielded a molded glass vessel and a large number of glass beads and inlays, as well as two more unusual vitreous vessels. This has led some archaeologists to speculate that glassmaking came to Egypt from the Syro-Palestine area during the reign of Thutmose III (Lilyquist 194).
Ancient glass was made from sand quartz (SiO2). Soda ash (Na2CO3) was added as a flux to lower the melting point of the quartz from 1723°C to 850°C (Bahn 322). If only soda and sand were used, the resulting glass would have been very low quality. So, limestone (CaCO3) was added as a stabilizer. This resulted in much higher quality soda glass with the chemical formula Na2SiO3.CaSiO3.3SiO2(Bahn 288).
5SiO2 (s) + CaCO3 (s) + Na2CO3 (s)‡ Na2SiO3.CaSiO3.3SiO2 + 2CO2 (g)
Ancient glass often contained iron and manganese impurities that gave it color. The iron and manganese impurities came from the soda ash or silica. The iron ions gave the glass a light-green tinge, and the manganese ions produced pink to violet colors. The beach sands used to make glass also contained sulfurs in the form of sodium sulfate (Na2SO4) that gave colors from yellow to dark green depending on the percent sulfur in the sand. The picture to the right shows a small light-green glass vessel colored with ferrous oxide (FeO) (Fleming 138).
Ancient glassmakers also purposefully added minerals to color class. Blue glass was made by adding copper compounds such as azurite (Cu3(OH)2(CO3)2), chrysocolla (CuSiO3.2H2O), and chalcopyrite (CuFeS2). Powder-blue shades resulted from using Egyptian blue (CaCuSi4O10). Darker blues were produced by added cobalt-rich minerals, such as asbolite (CoO). Green glass came from iron (II) compounds. Hues from pink to violet were the result of different manganese oxides (MnO). Yellows and umber were produced with iron oxides and carbon. A brilliant-yellow was achieved by mixing antimony and lead (in the form of bindheimite Pb2(Sb, Bi)2O6), which resulted in a yellow precipitate of lead pyroantimonate distributed throughout the glass mixture (Lambert 113, Bucat 288, Flemming 140, Hill 321).
Complicated redox chemistry was used by ancient glassmakers to produce red-opaque glass. To make the red-opaque glass, the glassmakers mixed copper and lead compounds and then had to keep the firing furnace oxygen free (reducing atmosphere). Even a whiff of air would have oxidized the Cu1+ ions back to Cu2+ ions, and the glass would have become blue. In the reducing atmosphere, cuprous oxide (Cu2O) crystallized throughout the glass mixture, giving the glass a rust-red opaque color. Even though making red-opaque glass involved complicated chemistry, near-eastern glassmakers were routinely making it by the ninth century BC (Fleming 143-4).
Not until Roman times was a source of silica found that was almost iron-free, so until then ancient glassmakers added antimony in the form of sibnite (Sb2S3) to decolor glass. This enabled them to produce almost colorless glass (Fleming 142).
In 63 BC, the Romans conquered the Syro-Palestine area. They brought back glassmakers to Rome. Soon after, the first transparent glass sheets were produced in Rome. The word vitrum, meaning glass, entered the Latin language (Lambert 113).
The final and greatest ancient technical achievement of glassmaking was developed around 50 BC. That was glassblowing. The technique was probably developed in Palestine, since the earliest blown glass was found at Jerusalem. Before glassblowing, only the very wealthy could afford glass items. Suddenly, glassblowing made the production of large numbers of cheaply made vessels possible (James 464).
With glassblowing, glassmaking techniques quickly spread to other parts of the Roman Empire and flourished until 400 AD. In fact, Roman output of glass was not matched again until the Industrial Revolution (Bahn 323).
Sources
Bahn, Paul. Archaeology: Theories and Methods 2nd ed. London: Thames and Hudson, 1996.
Bowman, Sheridan ed. Science and the Past. Toronto: University of Toronto Press, 1991.
Bucat, R.B. ed. Elements of Chemistry vol.1. Australian Academy of Science, 1983.
Fleming, Stuart J. Roman Glass: Reflections on Cultural Change. Philadelphia: University of Pennsylvania, 1999.
Hill, John. Chemistry for Changing Times 7th ed. New Jersey: Prentice Hall, 1995.
Lambert, Joseph B. Traces of the Past: Unraveling the Secrets of Archaeology through Chemistry. Reading: Addison-Wesley, 1997.
Lilyquist, C. and R.H. Brill. Studies in Early Egyptian Glass. New York: The Metropolitan Museum of Art, 1992.
James, Peter and Nick Thorpe. Ancient Inventions. New York: Ballantine Books, 1994.
I came across this great mosaic glass covered violin today that I wanted to share with my blog readers. It shows that you can re-purpose almost anything you can think of and create some amazing art out of it! I have also seen some stunning guitars done with mosaics.
* When drilling into glass, we advise glass artists to either drill in water, or hold a wet sponge on the drill bit, for safety reasons. This way glass dust cannot become air born and inhaled.
Ok, so you have read about the different kiln parts, but what do they look like? I know that when you first hear about all the different parts, it can be quite confusing. When purchasing a kiln for the first time, you need to know what parts are needed and which parts you can do without.
This page will give your some graphic pictures of some basic parts, and what they are used for.
All glass fusing kilns have the same basic components:
Elements (high temperature coiled wire) are usually embedded into the walls and/or top of the kiln.
Fire brick insulation on the inside of the kiln top, walls and bottom.
Stainless steel cover on lid and outside of kiln.
Thermocouple – high temperature wires covered by ceramic rings and placed through a hole to the inside of your kiln.
Infinite Dial – some kilns just have an on/off switch, while others have settings from low to high.
This is a Jen Ken kiln. Jen Ken kilns come in many sizes. Lets look at all the kiln parts that make up this unit. Kiln Lid: This is the lid of the kiln. You can see how the fire bricks are lined up to make this piece.
This is a top loading kiln, with a hinge. The outside is made of stainless steel. There are no coils embedded into the lid of this particular kiln. You can see that there is a chain securing the lid from being moved too far back on the kiln. A handle is used to open this lid to gain access to the kiln.
Kiln Latch: One of the kiln parts and features of this kiln is the latch. This allows you to lift the lid just a little to allow the unit to cool.
Infinite Switch and Pyrometer: This picture shows the kiln parts known as the infinite switch, pyrometer , and light indicator.
The dial is used to control the rate of electricity to the kiln. It is not like a regular oven dial that you can set to achieve a particular temperature. How high or low you set this dial will determine what percentage of time the heating elements are on, and how fast your kiln will heat up or cool down. This switch is used to go from a setting of low to high. The simplest control method is still turning the kiln on and off along with frequent observation of the item being fired, and adjusting this dial as needed.
The pyrometer has the readable face on one end and the thermocouple on the other end. You can't see the thermocouple here, because it is inside the kiln. This unit directly reads the temperature of the kiln.
The infinite switch and pyrometer is a dial type control of your kiln. This method is the cheapest and simplest device available for constant monitoring the inside kiln temperature.
Using an infinite switch and pyrometer do require continuous supervision and adjustment to achieve the best possible results.
Always use a timer with an alarm, when using this type of control over your kiln.
The black rectangle you see on the top right side is a light that comes on to tell you that the kiln is on.
Peep Hole: As you look around the side of the kiln, you will see the peep hole. When firing a piece, the hole is plugged with a peep hole plug. This is used for looking inside the kiln to check the status of your piece. Always wear safety glass when looking inside your kiln. The peep hole plug can also be removed for venting your kiln. The picture above shows the peep hole and the peep hole with the plug inserted.
Inside the Kiln: Ok, this is what the inside of the kiln looks like. You can see that it is built with fire bricks. You can see that the heating coils or kiln elements are in grooves in the fire bricks.
This picture shows a close up of the peep hole inside the kiln, and the coils going around the edges.
Kiln shelf and posts: The kiln shelf is usually round or square. This kiln supports the round shelf. The shelf should be at least one inch below the thermocouple. This picture shows the kiln shelf and kiln posts. The kiln posts are placed under the kiln shelf inside the kiln.
Thermocouple: A thermocouple runs from the pyrometer into the kiln. In a previous picture, I showed you the pyrometer on the outside of the kiln. The pyrometer has a thermocouple on one end, and it is inserted into the kiln. The thermocouple can become brittle from previous firings. When inserting the kiln shelf avoid hitting the thermocouple as it could break.
Hopefully by seeing pictures of the different kiln parts, you will have a better understanding of the different kiln parts and how they work.
This article, written about both leaded glass and faceted glass windows, has a lot of information for both stained glass artists and what to look for - for potential customers!
Stained glass is a general term covering all forms of
glass used in a decorative manner, primarily for windows,
but also for a myriad of secular uses prevalent today.
In as much as the stained glass craft is an adjunct of
architecture, this Association favors the principle of
architectural direction in the selection of artisans or studios
and the commissioning of stained glass projects.
Products of SGAA artisans are ideas and concepts
that are translated into site-specific designs satisfying the
requirements of the project, budget and schedule. We
believe that project success is better assured when a studio
is selected not on the basis of a “square foot” bid but
rather by virtue of artistic ability, imagination, past success
and, of course, willingness to work within the project
constraints of time and money. Consultation and design progress
review with the architect, client and artisan
should take place before construction documents are
complete. Early and regular review sessions are welcome;
such will save time and prevent the needless cost of
design adjustment.
Therefore, we believe that ideal conditions fostering
mutual confidence and the best practical procedure will
prevail when only one craftsman studies the problem
with the architect and client. Should such a craftsman fail
to provide a satisfactory solution, we believe that he
should withdraw, thus permitting another craftsman to
fully cooperate with the client.
If the prospective client wishes proposals from more
than one craftsman, we earnestly recommend the following
procedure:
1. A personal discussion is held with each craftsman
invited that determines the client’s likes and dislikes,
and to arrive at a general theme and style. If a special
sketch is required, the artist will then be able to create
the appropriate design.
2. The client makes known any budget restrictions. Any
one of our members will gladly assist in setting up a
practical budget.
3. The names of the craftsmen invited to make proposals
are made known to all concerned.
Consultation between architect, client and craftsman
should begin before contract documents are finalized.
Early cooperation will assure a well-integrated
design that considers all architectural, structural and
interior building elements.
Historically, SGAA artisans prefer that their agreement
be directly with the client, fully separated from the
general contract; however, all are vitally concerned with
the full satisfaction of the client and can adapt their
process to fit the project.
Leaded Stained Glass
The Process: The preparatory sketch is translated
into full-size mechanical drawings (cartoons) and further
into actual patterns to be used to cut the glass. Once the
patterns have been prepared and assigned color, the glass
is cut into the myriad pieces required to build the window.
When the design requires detail painting or ornamentation
of the glass surface, it must be done with pigments
designed specifically for stained glass. Once
applied, the pigment is fired in a kiln to the proper temperature
for the respective pigment, usually between
1000 and 1250 degrees Fahrenheit, thus assuring absolute
permanency. The pieces of glass are joined together with
lead came (H-shaped strips) and soldered at their intersections
on both interior and exterior surfaces of the
assembled panel of stained glass. Varying widths of lead
came are often used to add to the window’s decorative
effect as well as enhance its strength.
To prevent leakage, a mastic waterproofing material
is inserted between the glass and the flange of the lead
came. This process, often called “cementing,” is required
on both interior and exterior surfaces of the panel and is
paramount in weatherproofing as well as stiffening the
panel. It is recommended that panels be stored on a flat
surface for a minimum of two weeks prior to installation,
thereby allowing them to properly cure.
Reinforcing bars, regardless of the type, are typically
fastened or mechanically engaged at regular horizontal
intervals to the frame, sash or other substrate into which
the panel is installed. These surface-applied bars further
strengthen and support the installed panel of leaded
stained glass. Round bars usually measuring 3⁄8 inch in
diameter, tied to the panels with twisted copper wires, are
the most flexible and resilient, and therefore allow for the
greatest amounts of thermal movement. Where this system
is not suitable, galvanized-steel flat bars can be soldered
directly to the surface of the leaded glass panel.
Installation: It is recommended that leaded glass be
installed into frames designed specifically for that purpose.
Various types can be considered and include wood,
aluminum, steel, bronze and stone. Regardless of the type,
the most important consideration is that they are capable
of supporting the unique qualities of the type of stained
glass that is being installed. When possible, glazing beads
should be used in conjunction with modern, flexible
sealant systems to allow for flexibility as well as mechanical
engagement of the installed panels of glass.
The stained glass studio should be consulted as to the
best type of frame for the project at hand, the location
and placement of division bars, and mullion configuration
that will work best with the intended design. This
information should be finalized prior to ordering the
window frames or sash (usually supplied by the general
contractor on a new building) into which the stained
glass will be installed.
In general, the type of frame selected needs to be
capable of supporting stained glass weighing approximately
four pounds per square foot and configured with
mullions, allowing sub-division of larger areas into panels
of approximately 14 linear perimeter feet. In addition to
the overall structural requirements, the frames or sash
must include a glazing rebate that measures 3⁄8" to 1⁄2" wide
by 3⁄8" to 1⁄2" deep and allows the panels of stained glass to
engage into the frame or sash a minimum of 1⁄4". An
allowance of 3⁄32" to 1⁄8" between the stained glass panel and
Glazing Sealant: It is highly recommended that all
sealant be of the non-acetic gas-forming or neutral-cure
variety and that it be chosen based on the composition of
the materials and substrates to be sealed. Appropriate
bond-breaking tape and ethafoam backer rod should be
www.stainedglass.org www.SGAAOnline.com 3
used as required to achieve the flexibility necessary for
expansion and contraction of the finished installation.
Faceted Stained Glass
(Dalle de Verre)
Process: A twentieth-century innovation in the art
of stained glass introduced the use of glass dalles measuring
approximately 8" x 12" x 1". These dalles, cast in hundreds
of colors, can be cut into shapes and used, in combination
with an opaque matrix of epoxy resin 5⁄8" to 7⁄8" in
thickness, to create translucent windows and walls of
great beauty.
The epoxy used in the casting of faceted glass panels
must be a specially formulated slab-glass-setting compound
consisting of epoxy resin and hardener. The material
must be able to withstand temperatures of +130
degrees Fahrenheit on the exterior surface and a simultaneous
Everyone should check out Glass Fusing Made Easy's webpage, it is wonderful and full of valuable glass art information.
A glass kiln is an oven used for the glass fusing techniques. This is the most expensive item of all the fusing supplies. They come in a variety of sizes and shapes.
If you are looking to purchase a kiln, check out the great table top units at Delphi Glass - Art Glass Tools & Supplies. These are fantastic for fusing at home as they run on your household current.
They are usually lined with fire brick, which maintains the heat, and can support the objects being heated. The size is an important factor, because it limits the quantity and size of items that can be fired at one time. There are many parts to this heating unit.
Long ago, objects were fired in an open fire. The heat could not be measured or regulate, and the effects of a direct flame made it unmanageable. Over time, it was found that if objects were fired in an enclosed space, like a brick oven, you could achieve a higher degree of heat, and a slower cooling of objects. Glass has seen a rebirth in the past few years. It is used as a building material, a surface to paint on, engraved, cut, blown, slumped and fused.
Before purchasing, figure out the size that will fit your individual firing needs, whether you want a manual or a programmable unit , and find out what type of warranty comes with this appliance. Ask where and how you will get repairs done. What parts of the unit are replaceable and where you can purchase these parts.
Once the unit has been purchased, get to know your firing kiln . This will come in handy in any future firings.
Glass vs Ceramic Glass ovens heat single layers from the top, while ceramic units heat multiple layers from the side. Most glass projects are relatively flat, and with the heat radiating from the top, the entire face of the glass receives heat at the same time.
This helps to keep the temperature differences within the glass uniform and helps to prevent cracking. You can still obtain these uniform heating results in a ceramic oven by slowing down the firing.
An electric unit is the best for working with glass. The temperature can be regulated and controlled. They are also quiet, safe to operate, easy to handle, and fairly inexpensive to operate.
There are numerous types of electric units on the market, in a variety of sizes and accessories. These ovens are usually insulated, so there is very minimum external heat, and with no or very little fire hazard.
What Size to Purchase: Make a decision on how large the items are that you are going to make, that will help you decide the size to purchase. Find out the internal dimensions and external dimensions you need for the size of your desired projects. If you are going to use larger molds, will you have to fire on the bottom of the unit?
You need at least 12 inches clearance around the outside, so figure out where you are going to place it and make sure it will fit in this area.
Front load vs Top load: A front loading firing kiln is great if you are going to be removing items from the unit while they are hot. This is great if you are planning on doing any enameling.
A top loading kiln has either a hinged lid or one that can be lifted off with handles and removed completely. This is most commonly used for glass fusing.
Electrical Outlets: Know your electrical outlets. If you are glass fusing at home, then you will want a kiln that uses standard 120 volt, 13 amp household current.
You don’t want to have to do any rewiring to your home. It should have a three-prong plug and about an eight foot power cord.
Manual or Programmable: A manual oven has an on/off switch and a dial to adjust the temperature. There is small light to show that the unit is on and operating. They come with a pyrometer so the inside temperature is shown at all times. A thermocouple runs from the pyrometer into the oven. It should protrude into the firing chamber about one inch. Remember, the pyrometer will read the temperature where the tip of the thermocouple wire is, so put it near your shelf. These are not that difficult to use and don’t require that much more time or effort than a programmable unit .
Keep records of your firing. At first, set your timer for every 15 minutes, so you can see the rate of temperature for your particular unit. Keep records of the particular rates of temperature climb with each digit on your dial. Records will help you determine what works and what doesn’t work with each firing. Make detailed records of the total time it took from the start of your firing, to when you reached your desired temperature.
These records will help you in future firings. Then in the future, you can set your alarm to go off just before you know your oven should be at a particular temperature, instead of having to check it every 15 minutes or so. Always unplug your kiln when you are finished firing. Be sure to set an alarm clock to remind you when switches should be changed.
Brick or Ceramic Fiber: Firebricks are used as insulation in a brick oven. They heat more quickly and retain heat longer. These are great for glass fusing and annealing. More maintenance is needed because of the delicate nature of the fire bricks. The heating coils are placed in grooves in the fire bricks. If these coils should ever bulge out, they must be pushed back into place.
A ceramic fiber oven stays clean and is easier to maintain. The heating elements of these units are not exposed, because they are molded into the walls.
Kiln Safety: Even though a kiln will fire to a higher temperature than a stove, the area around the unit is surprisingly cool during firing. Glass kilns are well built and don't radiate a lot of area heat.
For safety purposes, the unit should not be placed within a minimum of 12 to 18 inches of any other object. It is recommended that the unit be placed on a flame retardant flooring. Some place the kiln on a stand on a flame resistant cement floor or fire board.
Be careful when opening the lid while the unit is at a high temperature. The heat will escape and rise. If you have low ceilings, cabinets, shelves, or other objects close by the heat will hit these items and could start a fire.
Always use common sense on what you have near or around the kiln. Be aware of where the heat goes when opening the lid during firing. If opening the lid while doing procedures like raking, etc. always unplug the unit before proceeding with the process.
Make sure that the power circuits are up to supplying the kiln. If there is a question about the supply, have an electrician check things out.
Furniture: The furniture consists of a shelf and shelf supports. These items are made of a highly refractory fire clay. The shelf material is quite strong, and should fit your particular unit. There should be about 1 inch of clearance between the shelf and the wall of the oven.
Furniture is inexpensive, easily available, and can be used over and over again. The shelf needs to be protected with either a wash, or fiber paper.
Care and Maintenance: When you first make your purchase, keep all the packaging material. If the unit needs to be sent back for repairs or replacement, you will be happy that you kept the original box and packaging materials. You first need to prepare the kiln and shelf for firing. Then you will be ready for a first firing of a fused glass project.
Use the shelf and posts. Having your items on these shelves allows air to circulate around your item and makes it easier to remove the shelf from the kiln. Place the shelf at least one inch below the thermocouple when firing.
Use protection on your oven and shelf. The unit needs to be coated with a wash. When coating the unit, it doesn't matter which wash you apply, just be sure to mix it about twice as thick as you would if you were using it to coat the shelves. Avoid getting any wash on the elements . Reapply the wash every few years. The shelf can be protected with either a wash or fiber paper.
Repairing coils might seem like a tedious task. See how simply this can be done without having to send your unit out for repair.
Periodically check and clean your thermocouple. This can be done using a damp cloth before firing your piece. Also check the position each time you start to fire. Try to avoid hitting the thermocouple with the kiln shelf, as it can be broken and damaged.
Check for any dust on the floor of your unit. Vacuum if necessary. Dust can react with the color elements in your glass and result in foggy or burnt colors.
For a small and inexpensive oven, try purchasing one that you can fire in the microwave . These are very limited in use and applications.
This is an excellent tutorial that even a non-stained glass artist can use! So next time you find a wonderful stained glass window but you are hesitant to buy it because of a hair-line fracture in a pane or multiple panes, at least now you can try to repair it yourself! If done correctly, the epoxy will fill in the crack so that it will not be easily visible, plus it will strengthen the broken pane of glass as well.
Use specially formulated glass epoxy to repair cracks in stained glass.
Cracks in stained glasswindows are sometimes difficult to repair without professional conservation procedures; however, for a stained glass window installed in a window frame and possessing only minor cracking, it is possible to repair the crack, at least temporarily, without dismantling the window. Using an epoxy commonly used by historical building restoration companies, the crack can be sufficiently repaired. According to the Building Conservation Directory, it is important to keep in mind that the epoxy used to repair the crack will break down in the sunlight over a long period of time.
Materials Needed:
Hxtal NYL-1 epoxy, or another UV light-resistant glass restoration epoxy
2 glass medicine droppers
Glass mixing container
Glass mixing rod
Self-adhesive forehead thermometer strip
Hair dryer
Toothpick or orange stick
Cotton rag
Razor blade
Instructions:
1
Mix the two parts, part A and part B, of the liquid epoxy by using glass droppers to add one part B to three parts A in a glass mixing container. Use a glass mixing rod to stir the two parts together. According to Talas, Hxtal NYL-1 is the only epoxy that won't discolor when exposed to UV light.
2
Stick a self-adhesive forehead thermometer strip onto the glasswindow near the crack so you can see the temperature of the glass.
3
Hold a hair dryer, set on a low heat setting, about 2 feet from the window glass. Heat the crack and the surrounding area to about 120 degrees Fahrenheit. Don't heat the glass quickly or let it get to a hotter temperature than 120 F. Gradually warm the glass.
4
Drop the epoxy into the crack using a glass dropper. If your window can be removed or can open at a tilt, this will simplify your repair, as you can drop the epoxy directly into the crack. If your window is installed upright, push the dropper as close to the crack on the surface of the glass as possible. Hold a toothpick or orange stick, a stick with tapered ends, beneath the crack and as you drop the epoxy, guide the adhesive into the crack with the toothpick or stick. Talas reports that the epoxy will soak into the crack very fast and will make finer cracks completely disappear.
5
Wipe away excess epoxy with a rag. Allow the repaired stained glass to sit undisturbed for at least 1 week. According to Talas, at a temperature of 75 degrees Fahrenheit the epoxy will reach about 90 percent of its bonding strength.
6
Scrape any excess dried epoxy from the glass with a razor blade after 12 hours have passed. Do not use any sort of cleaning product. After 24 hours, the epoxy can't be removed easily.
According to Hxtal, Hxtal NYL-1 is the leading epoxy used for glass repair and conservation. The British Museum uses this epoxy for repairs on priceless objects. This epoxy is clear and will not yellow. Hxtal epoxy is available at glass restoration companies and possibly at home improvement stores.
Most kilns come with a stock equipped manually controlled infinite switch and a pyrometer with a thermocouple. The thermocouple is attached to one end of the unit with a cable. This is one continuous unit, to monitor your kiln.
by Cheryl Collins
. These are fantastic for fusing at home as they run on your household current.
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