Frequently Asked Questions
Through the years, these are the questions our customers ask us most often. We hope you find these useful! If you don't see an answer to your question here, visit our Articles or MSDS sheets. Of course, we're always available to be reached by phone or email to answer any questions you have.
The Basics: Bisque
What is bisque?
The earliest ceramic bisque was pottery simply created from clay and hardened in a fire pit. Ceramics evolved to use glaze or glass like minerals to produce a more colorful, impervious surface. Ceramics include industrial, domestic use, building products and artistic pieces. The word "ceramics" comes from the Greek word keramikos meaning "of pottery" or "for pottery". The term ''bisque'' is of French origin and literally means "Twice baked" Ceramic bisque is not twice baked, only until after the second glaze firing. So the use of this terminology is interesting, since ceramic bisque really is baked only once.
For more information about bisque, click here.
What is clay?
Clay is a fine substance of dirt in which you can find at the bottom of a stream or river where they have bound to each other. Generally found along rivers or streams where the dirt is falling from the mountains or hills into the river. The Egyptians and Sumerians, generally can find a lot of clay because of their location near river valleys. The cool thing about clay is if dried in the sun you can make it soft again by letting it absorb water for one to two weeks. Though once clay has been fired or baked in a kiln you can no longer bring clay back to its original form.
What is pottery?
Pottery is usually deemed containers that are made from clay. Pottery derived from the Old English word ''potain'', which means ''to push''. As you can see it is easy to see the process behind the name as a potter pushes the pottery as the throw the clay on the wheel.
For more information on pottery, click here.
What is a kiln?
A kiln is a heating oven used to convert ceramics and glass at high temperatures. A kiln preserves history, as far back as ancient China when they made porcelain which is now priceless. Clay can be fired in a kiln to last for centuries and permanently decorated with glazes for desired aesthetic. A kiln is also capable of fusing pieces of glass to form original pieces you can display for others to see. You may also slump or drape to create a plate, bowl, lamp shade, or even cigar dish. Kiln is capable of hardening, heating, melting and fusing. The possibilities are endless.
To shop our selection of kilns and accessories, click here
Best Practices: Bisque
How should I fire your pottery?
Our bisque is low-fire earthenware. Therefore, it should be painted and fired to cone 05 or cone 06 in a ceramic kiln. For durability and food safety, we recommend three full coats of glaze on all areas of the bisque. Many choose to dip in a clear dipping glaze after painting to insure beautiful shine.
What are witness cones?
Pyrometric witness cones are used to measure the effects of both time and firing temperature inside a kiln. We recommend using cones in every firing to make sure your kiln is firing correctly.
To learn more about witness cones, click here.
How quickly can I cool my kiln?
Patience is key. Opening the kiln is always exciting. Too often people will try to open it too soon, which may lead to issues down the road. Wait until the kiln has cooled below 100 degrees before opening your lid.
As you unload the kiln, make notes in your firing log regarding how the cones looked, how the kiln was loaded, how the bisque fired and how long the firing took. This will help you make adjustments on your next firing.
How should I prepare my pottery for painting?
We recommend lightly wiping the ware with a damp or dry sponge. This will quickly remove any dust that has settled on the surface. Avoid touching the ceramic bisque with lotions, creams, or other oily products.
Technical Questions: Bisque
How do I clean up a mistake on my unfired pottery?
There are several ways to fix a mistake. If the paint is wet, you can either wipe the area with a damp sponge or cotton swab. If the paint is dry, carefully scratch off the area you wish to remove with a wooden skewer, the tapered end of a brush, or a clay tool. If you wish to completely start over, avoid running the bisque under water to remove paint. Instead, carefully wipe away the paint with a damp sponge.
How do I fix a mistake on my fired pottery?
There are several ways to fix a design mistake on fired ceramic bisque. If it is a glaze issue, please visit that section of the FAQ area for more information. To remove something that should not be there, we recommend lightly sanding the area with a sanding tool. Lightly touch up the sanded area with glaze and refire in your kiln. To add something you missed, like a name on an auction piece, simply paint on top of the area you wish to add to and refire.
What products should not come in contact with my pottery?
Oil and excessive amounts of water should be kept at a distance from your pottery. Both will resist the glaze and the water will keep the underglaze from absorbing into the bisque.
How do I remove stilt marks?
Stilt marks can be removed by gently sanding the marks off with a stilt stone SST-100. Be careful not to scratch the glaze. Use a circular motion to sand the sharp or rough spots off. You can find stilt stones here.
What is shivering?
Shivering takes place when the paint and glaze chips or flakes off after being fired in the kiln. Thermal shock is a direct result shivering in most cases. Thermal shock is when the cool down process happens too quickly. Shivering can also be a quality issue from the bisque or underglaze used. Old or low-quality underglaze or also a bad batch of bisque from your bisque supplier can cause shivering when removing from the kiln.
What is crazing?
Crazing is when the overglaze starts to crack over a period of time. It happens from heat exposure and use over time. For a more in-depth explanation, click here.
How do I prevent crazing?
To prevent, you can hand wash pieces and avoid placing in the dishwasher and microwave. To fix crazing you can refire the piece as well at cone 06.
Why is my glaze resisting the pottery?
There are several possible reasons for this. The natural oils from your hands may have transferred to the bisque. Also cleaning products will create hard spots that will resist the glaze as well.
Something fell on my pottery during firing. How do I fix this?
If something has fallen on your pottery during glazing, you should most likely be able to do some repair work to fix it. If a piece of the kiln brick or a chunk of bisque fell on your pottery you can use a stilt stone SST-100 and gently sand it off using a circular motion. If the piece that fell on your pottery is big and a bit more stubborn, you can sand it off. Once you have sanded down the area, reapply some glaze and re fire.
How do I attach Tots and Add Ons?
For flat items such as plates, tiles and plaques, simply position the add on where you want it on the piece and fire. For pieces such as vases and figurines, we suggest firing the tot or add on separately, and attaching it after both pieces are fired, with E6000 glue. Tape should be used to hold the glued on piece in place for 24 hours.
The Basics: Paints and Glazes
Click here for a quick definition of Ceramic Glaze!
What lines of paint do you offer?
We offer Duncan and Colorobbia. You can find all of our paints here.
What is the difference between glaze and underglaze?
Underglaze, or paint, requires a clear glaze to seal before placing in the kiln if three full coats of paint have not been applied. Dipping glaze is the final product you put on a piece before being fired to create all over shine. There are glazes that are paints as well - like Duncan Crystals, etc. that you paint on the bisque and do not require a clear glaze.
Do I have to dip my ceramics in glaze?
An alternative to dipping glaze is a brush on glaze. Also, you can paint with three solid coats of paint before firing in the kiln. Anything that is not painted with three solid coats all over won't be food safe, and you must be sure to use three solid coats of paint and no less.
Are your glazes and paints toxic?
We do not sell toxic glazes or paints.
Is there lead in your glaze?
Our glazes do not contain lead.
How do I clean glaze off of clothes?
A good wash will remove glaze from dark colored clothing and will stain some light-colored clothing. Use an apron when painting and dipping to avoid this. Using our Leatherbak Splash Shield when dipping can protect your clothes and kiln room from being exposed to glaze.
How do I use specialty glazes?
Each line of specialty glaze will have a slightly different set of instructions. For full details, click here
Can I mix paints?
You can mix paints from the same line. For example you can mix Concepts with Concepts or Cover-Coats with Cover-coats, but you can not mix Concepts with Crystal glazes or Cover-coats with Concepts.
Does paint stain?
Most paint does not stain. However, we do recommend running the piece of clothing under water should you spill it on your clothes.
Best Practices: Paints and Glazes
How should I set up my dipping area?
You will want to have a space dedicated to dipping. You will need to have a dipping vat, large storage bin or medium sized trash can with a lid that snaps closed to keep your dipping glaze in. Metal wire shelving with Glaze Drying Mats are ideal for storing.
How can I dry my paint between coats?
If painting multiple items you can paint in sequences, paint the first coat for all and by the
time you get to the first item it should be dry.
How many coats should I use?
It is recommended that you use three solid coats of paint on bisque.
What if my paint becomes dry or thick?
You can shake your paint if it has settled, though if your paint has dried or is extremely thick please inform your supplier.
Can I place glazed pieces directly on my kiln shelf?
No, it will fuse to the shelf.
How and why should I strain my glaze?
Use a strainer and wait for glaze to flow through. You should strain your glaze to keep clean and remove any residue from previous pieces that have been glazed. Be sure to strain the glaze each time new glaze is added to remove any foreign matter.
How do I mix my glaze?
Click here to watch a short video on glazing, or follow these step by step instructions:
Mix the glaze using a plastic or stainless steel paint mixer (others may rust and affect the glaze) with a drill to stir initially for 10 minutes. You should also mix the glaze in the same manner before each glazing session for 2 to 4 minutes.
Mix from the bottom up (in layers). Water is at the bottom of the bucket instead of having a water head. Mixing brings the water up through the glaze.
Rinse mixer with water after use.
After the initial mixing, add 4 ounces of distilled water to a 3.5 gallon bucket so that you may check the viscosity. Add 8 ounces to 7 gallons of glaze. After the first viscosity check, add 2 to 4 ounces of water at a time while mixing the glaze. Stop to check the viscosity after 2 minutes of mixing. Remember, a little bit of water goes a long way with this glaze. This is a solid (gel) glaze and it should be kept solid to function properly.
Use a wire whisk to mix the glaze every 10 minutes during a glazing session.
Pinholes on glazed piece will heal during firing.
This glaze is not transparent when dipped. You will not see the color/design through the glaze after dipping.
Should I sand glazed pieces before they are fired?
No, use a pot scraper to move glaze (dry or wet) from the edges of the dipping tank. This may fall back into the tank as it will reconstitute during mixing. If glaze is too thick, looks matte or cloudy or has bubbles, simply re-fire piece. The excess glaze will fire away.Use a palette knife to gently level off any drips that may occur. Finger sanding is not needed so you can avoid creating excess dust.
How do I clean my glaze bucket?
Save your glaze, do not throw away good liquid glaze. Glaze does not go bad, so pour your good glaze into a separate container and scrape the side of the glaze bucket to get out any harden glaze and spray down with water to remove all excess glaze. Once all glaze is removed place pervious glaze in the bucket and add more glaze if needed. Do not forget to take the steps needed to check the viscosity of your glaze.
Technical Questions: Paints and Glazes
My dipping glaze seems very thick. How do I fix this?
Check the viscosity of your glaze and whisk in small amounts of distilled water while still measuring each time until you reach your desired viscosity.
My dipping glaze seems very thin. How do I fix this?
Some glaze may thicken over time. If not, try adding another bucket of glaze to properly mix the two glazes together. If problem continues, please contact supplier.
How do I check my glaze viscosity?
Checking your viscosity is very important! You need just a few things. A viscosity cup is most important! You will also need a gallon of distilled water which you can find at your local grocery store. Click here for step by step instructions on how to check the viscosity.
Viscosity Cup Item# VC100 has twice the volume than the typical viscosity cup. When measuring clear glaze for viscosity use a stop watch or timer to calculate how many seconds it takes for the cup to empty or for there to be a break in the stream. Start the timer immediately after lifting the viscosity cup out of the clear glaze. Take that number and divide it by 2 to get the accurate viscosity reading.
How do I eliminate glaze overlap?
Begin with glaze that has been mixed and is at the proper viscosity. Glaze one half of the bisque and allow it to dry; once dry dip the other side and try to avoid as much overlap as possible. If overlap occurs, use a fan brush to soften the the glaze line on the bisque.
What is the difference between half glazing and using dipping tongs?
Half glazing is glazing one half, letting it dry and then glazing the other half. When using dipping tongs you dip the entire piece into the bucket and no double dipping is required. It comes down to personal preference!
What are oolites?
Oolites are little pebbles of calcium carbonate. These pebbles form naturally and it is unclear their reasoning for formation. Though during warmer temperatures and vibration while glazing seems to be factors. Oolites can be removed by straining glaze.
What if my glaze appears dull or cloudy?
If glaze is too thick, looks matte or cloudy or has bubbles, simply re-fire piece. The excess glaze will fire away.
How do I prevent sprinkles, crystals, shimmers, fairy dust, etc. from getting on my other pieces?
Dip these piece in a separate glaze container in order to prevent these particles from transferring onto other pieces.
My stilts are stuck in my pottery piece. How do I fix this?
Pull the stilts out, but note that this is a sign that your glaze is too thick.
Something fell on my pottery during firing. How do I fix this?
If the object can be pulled from the bisque and the mark is small you can sand it down and add a spot of glaze to the mark and fire again.
Crafts, Acrylics, Mosaics and More
What are acrylic paints?
Acrylic paint are essentially gel-like to runny liquids made of a mixture of plastic and pigment. They dry true so the crafter will have an idea of the finished design and tend to resist water. You can view all of the acrylics we offer by clicking here.
Are acrylic paints food safe?
The acrylic paints are non-toxic, but have not been approved for contact with food. We recommend them for use on decorative pieces.
What can I paint with acrylics?
Canvases, wood, clothing, paper, and craft bisque are a few of the many items you can paint with acrylics.
Do acrylics stain?
Yes acrylic paints will stain your clothes. So it is always great to have aprons available for your customers and campers.
How do I seal my acrylic paint?
We have to sprays available to seal your acrylic paint. There is the Clear Matte Spray that produces a smooth, even, flat-matte finish on non-fired acrylic and translucent colors. Also Bisque Imports has a Super Glass Sealer Spray which is a final spray coating that produces a smooth, hard surfaces and used to brighten colors and protect finishes of the objects decorated with non-fired color products. Click here to view our sealer sprays.
What happens if I fire acrylic paints?
You should never put craft bisque or bisque item with acrylic paint in the kiln as it will resist and burn off of the bisque.
How long do acrylics take to dry?
Acrylics when applied correctly take minutes to dry as it is not a long movable paint you must paint with it a quick manner.
Are acrylics safe for children to use?
Acrylic paints are non-toxic but are not meant for food container items. These paints are great for children to use and offers them great versatility as they can use it on many different items.
What are mosaics?
Mosaics are a form of art where one places small piece of tile and glass together to create a pattern called tesserae. For several mosaic tutorials, click here.
What are tesserae?
Tesserae is an individual tile formed into a shape that is used in creating a mosaic.
What are mosaic tiles?
Mosaic tiles are tumbled pieces of glass with smooth backings that come in a variety of colors from glitters and foils to gold-veined and liquid. Check out Bisque Import's large assortment of every mosaic you would need. We offer a great variety of mosaic tiles to choose from, which you can view by clicking here.
What is grout?
Grout is sanded or non-sanded cement that is used to fill the space between tiles or tesserae in order to support them and protect the substrate. You can find our grout here.
What is the difference between the different mosaic tiles?
The difference in the mosaic tiles available here at Bisque Imports the sizes available and styles used to create the mosaic tile designs.
What glue should I use for mosaics?
For general mosaics use Weldbond a non-toxic, weatherproof, virtually odorless, dries clear and cleans up with water. You can find Weldbond here.
What glue should I use for photo mosaics?
For photo mosaics use Aleene's Glass & Bead Glue it is a quick-setting adhesive for use on glass, beads, mirrors, ceramics, and more. You can find it by clicking here.
Are mosaics food safe?
Mosaics are not food safe.
Are mosaics weather resistant?
Mosaics when grouted and glued with Weldbond are weather resistant.
Can I change the color of my grout?
Yes, the color of your grout may be changed by mixing with a small amount of diluted acrylic paints or painting over the grout once it has dried. Click here to watch our grout coloring video.
How should I clean my mosaic after I grout?
Wait thirty minutes for the grout to harden once it has been placed onto the mosaic base and wipe off any excess grout. Once the grout has completely dried you can wipe off with a wet paper towel in order to remove any excess grout on the tiles.
How do I clean grout off of tables?
Place a tarp or plastic wrap on your table before beginning to grouting process to avoid getting grout on your tables.
What are some different mosaic techniques?
You can use full tiles to fill your base or use wheel mosaic nippers to cut tiles to desired size then use tile pieces to fill your base. Also you can use clear tiles to create a photo mosaic. For more ideas, visit our mosaic resources section by clicking here.
How do I finish the sides of my mosaic?
When grouting your mosaic you have one of two options. Rub the grout on the sides in order to finish the piece or once the piece is dry you can paint the sides with acrylic paint that coordinates with the colors chosen in your mosaic.
What is warm glass?
Warm glass is kiln-fired glass. This can include fusing, slumping, draping, casting, and other techniques. This is not stained glass which is not fired and it cold glass or blown glass which is done in a furnace at higher temperatures. For a more in-depth explanation, click here.
What is glass fusing?
Glass fusing is the technique used to join glass pieces together by partly melting the glass at high temperature. The heating is done in an electric kiln. Click here for more information.
What is COE?
COE is the Coefficient of Expansion. All glass need to have the same COE in order to prevent cracking as it expands and shrinks. The lower the COE is requires a higher temperature to melt the glass. COE 96 is offer at Bisque Imports in our Warm Glass Department.
Can I use any type of glass?
When using glass you can only use one COE for all glass in that project. Using multiple COEs will cause cracking due to different reactions at various temperatures while being fired in a kiln.
What is shelf paper?
Shelf paper is fiber paper and works just like wax paper does while baking cookies. Shelf paper is used to protect the project from the kiln shelf so it does not fuse to the shelf. You can find our shelf paper by clicking here.
What is slumping?
Slumping is a technique used in order to take a glass project from its flat form and give it dimension. You can slump glass in a bowl, plate, tray and other ceramic molds in order to receive desires shape. Always make sure to use glass separator in order to prevent glass from fusing to the mold. Click here for more information.
What are slump molds?
Slump molds are ceramic pieces in the form of a bowl, plate, kitchenware or serving ware and other shapes. In order to slump a piece into the desired form of the piece you are able to place a fused piece or raw glass on the mold.
What is draping?
Draping is similar to glass slumping as you are creating a desired look from a square or circle piece. By draping you place the glass piece on the drape and the piece is pulled down around the drape to achieve a unique pieces every time. With draping you can make light pendants, bowls, lamp shades, cigar trays, vases and more the possibilities are endless.
Do I need a separate kiln for glass?
No you do not need a separate kiln for glass all you need to do is make sure you kiln has an electric control panel in order to set firing schedules.
How do I fire warm glass?
Firing warm glass in a kiln with a electric panel at your desired firing schedule will fuse the glass to your liking. There are three different types of firing full fuse, contour, and tac. Full fuse is when the glass is melted together and has a smooth surface. During a contour the glass is fused together with smooth edges but leaves dimension on the piece. Tac is simply the glass completely fused together with sharp edges and still its in original state.
Do I need separate kiln shelves for glass?
No you can use your same kiln shelves you simply need to place shelve (fiber) paper on the shelve in order to keep your glass from fusing to the shelf.
How do I cut glass?
You can cut your glass with a glass cutting system or tools in order to get a desired shape. It is suggested that you purchase as many pre-cut shapes as possible in order to prevent a waste of glass and save time when making a glass project.
What tools do I need to get started?
Running Pliers, Breaker/Grozer, Pistol Grip Glass Cutter, Wheel Mosaic Nipper, are all tools you need in order to start cutting glass.
How much glass do I need to get started?
The amount of glass you purchase for your studio depends on your customer base and the area and which you are placing your glass. Refer to these studios to show you the variety of ways to display your glass. If you are interested in starting warm glass at your studio, call us today and we will be happy to provide you with everything you need! We also have Warm Glass Starting Kits - which are a great way to jumpstart your warm glass program.
How can I track customer glass pieces?
Silver Sharpie doesn't burn off in the kiln - so you can write their initials on the fire paper as you place the project in the kiln. Or you can write descriptions before you fire the projects.
How do I charge for glass?
When pricing your glass offerings, be sure to cover your costs for all supplies used and the fuse firing. If you are going to slump a piece, be sure that the mold is primed prior to beginning the glass fusing process allows adequate time for the mold primer to dry. Following is a list of suggested retail prices for your reference. Slumping requires a second firing and customers are often charged a slumping fee of $6. Click here to view our Glass Pricing Article.
Should I offer glass on a walk in basis?
Yes glass if they have taken a beginners class or has worked with warm glass in the past.
How many layers should a glass project be?
Most projects are two layers thick. You may choose to add a few accents on top as a third accent layer. Remember that the more glass, the heavier the project is and could causing cracking or bubbles.
Should I allow my customers to cut glass?
Yes, but make sure your staff is prepared to provide proper training. We recommend only allowing adults to cut with the proper tools, gloves and protective eye wear.
How do I make kid friendly glass?
Take any scrap glass you have cut the down into small pieces and full fuse all the glass on fiber paper and there goes a large assortment of kid friendly glass for your young vibrant customers.
How quickly can I cool my glass?
We suggest that you let glass cool down in the kiln to room temperature in order to prevent thermal shock and cracking throughout the piece.
Should I use my kiln vent during firing?
It is suggested to not use a kiln vent while fusing glass, as this may stir up the fire paper during the firing.
How often should I prime my molds?
When using glass separator you need to prime after 20 firings. When using boron nitride spray after 4-7 firings you need to prime your molds again. If they seem to be sticking more than usually add some more primer.
What primer should I use for bisque molds?
Glass separator or Primo Primer. For fusing pod and frit casting molds, we recommend Boron Nitride Spray. You can view our Primo Primer by clicking here, and our Boron Nitride Spray by clicking here.
What primer should I use for stainless steel molds?
The only primer you should use on your molds is Boron Nitride spray. You can find it here.
How much glass should I be using?
The glass you use will determine on the project you are making and the amount of people replicating the project.
How thick should I build my glass?
Glass always likes to be a quarter of an inch thick so keep that in mind when making your glass project.
How close can I fire glass in the kiln?
Glass should at least be one inch apart for another glass piece in the kiln.
What should I do with my scrap glass?
Come up with new innovative ways to make glass projects for customers to replicate. Also scrap glass can be used to make kid friendly glass and organized for customers to use when making a glass project but using a different color than you have chosen for your piece.
What type of glue should I use on my glass projects?
GlassTac or Klyr-Fire glue are the recommended glues to use on your glass projects.
Why am I getting bubbles in my glass pieces?
Bubbles form when air is trapped between kiln shelf and glass and is trying to escape through the glass.
Why is my glass cracking?
Cracking happens during thermal shock or your project was uneven and the glass was too heavy in one place for the entire piece.
Why is my piece stuck to the mold, and how can I get it off?
Always make sure you spray or paint three layers of primer onto your mold before slumping or draping. If you have done this you can flip your mold over on stilts and hold at 500 degrees for 30 minutes which will loosen up the fused piece from the mold.
Why are there dark spots on my project?
Dark spots form from using too much glue or hairspray on your project.
How do I adjust my firing schedules?
It is not recommended that you change your firing schedules. Contact us with any questions before changing a segment.