Kiln wash your kiln!

This is a MUST DO maintenance tip for anyone that is melting glass in a kiln, or annealing lampwork beads as well.  Make sure that you have thoroughly kiln washed the interior sides of your kiln also the floor of the kiln, kiln lid, and any kiln posts and shelves that will be inside your kiln when firing!  The reason for this is to keep any molten glass from permanently adhering to your kiln and perhaps ruining it!  Without kiln wash, molten glass will permanently stick to your firebrick and kiln shelves.  And when that happens, you will have to remove all firebrick that has been contaminated with melted glass since subsequent firings will make that glass only melt deeper and further into the firebrick.

I just mix up Primo Primer Kiln Wash in a little plastic bucket and paint it on my kiln with a Hake brush.  It can last many firings!  My kiln shelf is done the same way but occasionally I have to scrape the old kiln wash off it and then reapply.  I put about three coats on the shelf, waiting for the kiln wash to completely dry between coats.  When applying to the kiln walls and lid, be sure to keep the wash off of the elements.  

Below is a picture of what I found inside my kiln this morning.  As you can see, the top green bottle rolled off of my kiln shelf and ended up on the kiln floor and partially up the wall.  Since I had all firebrick and kiln furniture kiln washed, I could just pick up the bottle without it sticking anywhere!

 YEA!

Preparing a kiln shelf for fusing glass, video

This video shows Erwin Timmers, the co-founder and co-director of the Washington Glass School where he teaches glass, lighting, sculpture, and metal work.  The video is great reference material for new glass artists wanting to fuse glass in a kiln!  

Click HERE to view this video.

How to use glass casting molds, tutorial

This tutorial came from GlassCampus.com and is full of excellent information.   Check out their website for many more informative tutorials!


Using Casting Molds

PREPARING THE MOLD
Carefully clean the mold to remove any dust and
scrub out any remaining kiln wash from previous
firings.  Single-use kilnwash like “Hotline” is
preferable to multiple-use kilnwash like “Bullseye”
because it’s easier to scrub out.  An old used
toothbrush is an effective tool for removing kilnwash
or a bristle brush on a Dremel will speed up the job.
Prepare the mold with 3 or more coats of thin kiln
wash.  More thin applications are better then few
thick coatings.  Be careful to not apply so much kiln
wash that you fill in all the detail in the mold.  Don’t
just coat the inside part of the mold that will be filled
with glass, but also coat the top upper surface.  Any
small pieces of glass that are left on that surface
will become permanently embedded into the mold if
you don’t.

FILLING THE MOLD
The glass level will drop as it melts into the mold.
Take care to be sure you  have enough to fully fill
the mold.  The smaller the pieces of glass you use,
the less it will sink.  On average, the finished
casting will be about half the depth of the loose
filled mold.  Because the glass level drops, you may
prefer to fill part of the mold with a pieces of glass
stood vertically to provide the extra glass needed to
fully fill your mold.

FRIT & POWDER
Glass powder and very fine frit doesn’t stay
transparent but will turn slightly opaque making the
finished casting looking more like alabaster then
glass.  Some attractive special effects can be
achieved by putting small amount of glass powder
in the details of the casting and filling with larger
pieces of a different colour.

FIRING SCHEDULE FOR CASTING (COE 96)
1. 800 dph to 1475°F hold 20 min
2. FAP to 960°F hold 30 min
3. 600 dph to 300°F OFF

FINISHING THE CASTING
Your casting will have some spikes along the
edges.  You can cold finish to remove them – either
by hand or with a grinder or wet belt sander.  The
casting will also have some texture from the mold.
You can remove the texture and smooth off the
scratches from cold finishing by turning the casting
over and returning it to the kiln to fire polish.

FIRING SCHEDULE for FIRE POLISH
      1    500 dph to 1000°F hold 20 min
     2  1500 dph to 1300°F hold 5 min
     3    FAP to 960°F hold 60 min
     4    500 dph to 200°F OFF min

The above firing schedules are for COE 96 glass.
For COE 90 add 20°F to all top temperatures.
For float glass add 50°F.

Video showing how to apply Boron Nitride Spray to a mold

This is a great video made by Colour de Verre Molds showing how to use MR-97 Boron Nitride Spray on one of their molds.  The spray is a great way to prime molds for firing without having to use kiln wash.  It is easy to use on steel molds, too!

Watch the video here!

Preparing steel molds for glass fusing

We recently bought a few new steel molds for the studio and needed to get them primed so that they'd be ready for fusing.  Just in case you are new to fusing with steel molds, you will discover that kiln wash will NOT stick to a steel mold without heat and perhaps, as I have come to find out,  a little luck as well!  

Unfortunately we forgot how to get kiln wash to stick nicely to new steel molds, since we hadn't bought any new steel molds in a long time.  A lot of glass artists use Boron Nitride spray on their molds but we already have Primo Primer on hand, so that is what we used.  We didn't apply the shelf primer on the molds while in the oven.  Instead we removed the molds (one at a time), painted, then put them back in the oven to heat up and also dry.  A lot of glass artists put their molds in their kilns to heat up but our kiln is large and it is fairly inconvenient to heat them that way.  We have also heard of other artists placing their steel molds on top of their kilns while they are running, but our kiln is very efficient and not enough heat escapes the lid to be able to heat the molds to an adequate temperature.

Above: New steel molds in the kitchen oven, heating up before applying kiln wash.  We prefired the molds in our kiln to 500 degrees and cleaned them.  We didn't use sand paper or Brillo pads on these but we see that a lot of glass artists suggest using them to rough up the surface allowing the primer to stick more easily.

Above: Kiln wash mixed in bucket with hake brush ready to use on the steel molds.

Above: Picture showing partially painted molds.  The mold on the left wasn't hot enough to allow the primer to stick on the lower section.  

As of today, I still haven't gotten my kiln wash (Primo Primer) to stick the way it should on the molds!  I lowered the oven temperature to 200 degrees but that didn't help.  I also used sand paper and roughed up the lower section of the smaller mold where the wash wouldn't stick at all but it still didn't work!  Right now I've been working on these for three days, without luck!  

As soon as I figure out what works for these molds, I'll update my post.  Perhaps I'll buy some Boron Nitride spray after I try this a few more times.

So far some suggestions have been to use sand paper or a sand blaster to rough up the metal.  Another is to heat mold in sections with a heat gun and apply primer.  Another idea, mix my primer thicker.  Also some say they spray it on with an airbrush (I don't have an airbrush).  Others say wash it first with rubbing alcohol.

Ok so this afternoon I worked on the molds again.  I washed and removed all the old kiln wash off the molds.  I then used a little electric sander and sanded the surface area on the molds and once done I cleaned them with rubbing alcohol.  I then set my oven to 225 degrees and put the molds in.  I mixed up my primer so that it was fairly thin.  Once a mold was heated, I removed it and then quickly painted on a very thin layer of primer with my hake brush.  After that I put the mold back in the oven and set the timer for 5 minutes.  When the timer buzzed after 5 minutes I put another thin coat of kiln wash on the mold and then put it back in the oven.  I repeated these steps, with all molds until they appeared to have enough primer coating to work when fusing.  Finally, it worked!

Above: Molds with kiln wash properly applied and now ready for fusing!  The mold on the left is a floral former, the one on the right is a pendant light mold.

How to remove kiln wash from glass

Trying to remove baked on kiln wash from the underside of a glass piece can be one of the most frustrating experiences for the warm glass artist.  In the worst cases, it doesn't respond to elbow grease, it requires nasty chemicals, and it leaves an ugly stain behind. 

But there's no need to despair, there are several ways to remove the baked on primer.  Part one of this two-part tip deals with less aggressive, relatively simple and safe, methods of attacking the baked on kiln wash beast.

1.  Vinegar.  Soaking the glass in distilled white vinegar (a mild acid) for two to three hours will often help the kiln wash come off with a minimum of scrubbing.

2.  Acid Etch or a similar etching product -- although this will leave a matte finish (not unattractive, by the way), a simple soak for ten to fifteen minutes will usually remove the kiln wash completely.

3.  Old fashioned elbow grease -- either after soaking in water or vinegar, or just by itself.  A good scrub with wet/dry sandpaper, Fabricut (open weave sand paper), or a similar product can work well. 

This information was found on Warm Tips.  Check out this web page for a lot of excellent warm glass hints and tips!

Our bottle slumping notes

Bottle slumping (and melting them flat) is one of the most inexpensive and fun kiln projects available for glass artists!  Typically an artist will have to buy glass from either a retail store or wholesaler to make their hot glass project.  With bottles and jars, an artist only needs to find a source for the free glass.  They can find an excellent source through friends and even themselves.   Once a free glass source is secured, the only costs involved come from the expense of shelf paper, molds, kiln wash, and devitrification spray.

We have decided that there are two types of wine bottles (and glass jars).  One type has a flat bottom while the other has a conical bottom.  When slumping a plain, non painted bottle or jar, it really doesn't matter how the bottom looks when finished.  When slumping a painted bottle or jar with a flat bottom, more care must be taken so as not to allow the bottom to completely fold over the painted area, thus obscuring part of the image.  To do this, a bottle or jar should be only partially slumped, so it must be watched, sometimes minute by minute,  at the very end of the kiln firing process to make sure that the slump is stopped before the bottom of the bottle folds over completely.  Another way to completely melt a bottle or jar with a flat bottom is to lay the bottle with the front side laying on the kiln shelf (with shelf paper underneath).  Once melted flat, the bottom of the bottle will be melted flat onto the back of the bottle.  Unfortunately the front side of the bottle will not not have a glossy finish if done this way.  So if a glossy finish is wanted on the front of the bottle, it will have to be re-fired with the front side of the bottle facing up, this time.  We have found that when firing a bottle or jar for a second time in our kilns, we must slow down our firing schedule or the bottle will break.  The schedule not only needs to be slowed down during the heating process, but also during the cooling process as well.

Bottles with a conical bottom are quite easy to melt since when completely melted, the cone shape easily flattens out inside of the bottle so it is not visible on the outside of the bottle.  These bottles work great in wine bottle molds and melted flat on a kiln shelf.

We advise glass artists to always use shelf paper.  We like Bullseye thin fire shelf paper, it doesn't have a texture that can mar a glass surface.  It is easy for a bottle to end up with permanent kiln wash marks or stains when a bottle is laid on a kiln shelf or in a mold without any shelf paper as a buffer.

It is also important to use some sort of devit spray on bottles and jars.  Although some artists seem to like the look of devitrification,  most don't.  We like to use the borax soap mixture on our bottles and jars.  It really works and it's easy to make, click on this link to go to our Borax devitrification spray information page!

Blue and clear bottles and jars seem to get devitrification easier than green and brown bottles.  For that reason, if you don't want devitrification, you have to speed up the time on your kiln schedule from 1300 degrees to the hottest temperature desired.  The less amount of time spent in the that temperature range, the less chance of getting devitrification on your glass.

How to put kiln wash on a stainless steel mold.

Some molds, notably those made of stainless steel, do not always respond to the room temperature brushing or spraying techniques that are used with ceramic and other items. As a result, you need to heat the stainless steel mold in order to get the kiln wash to stick.

To do this, place the stainless steel item inside the kiln. Leave the lid or door of the kiln open slightly, just in case any fumes build up and need to be vented. Then heat the kiln to a temperature of about 500 degrees F. Control the kiln so that this takes about half an hour. Taking longer is perfectly acceptable.

While the kiln is firing, prepare your kiln wash materials. You'll need some kiln wash and either a soft, wide brush or a sprayer or airbrush. Lay the items you will need on a surface that won't catch fire if something hot is placed on it. 

You may use either a brush or a sprayer, but be aware that using a sprayer or airbrush on stainless steel molds will result in a smoother finish than using a brush. In addition, some artists also use a mask when mixing and spraying kiln wash. This keeps you from accidentally breathing in kiln wash particles, which can be harmful if inhaled.

Once the temperature in the kiln reaches 500 degrees, turn off the kiln. Put on your gloves, reach inside the kiln, and carefully remove the stainless steel item. Place it on the nonflammable surface, next to the kiln wash.

Spraying on kiln wash is a simple matter of applying a thin, even coat of kiln wash on the outside surface of the mold. The kiln wash will sizzle as it goes on. That's the sound of the water in the mixture evaporating and leaving the protective powder behind.

If you've decided to apply your kiln wash with a brush, make certain you've selected a brush that will resist the heat of the stainless steel. Foam brushes (and some haike brushes) will not work, but most good quality paint brushes can withstand the heat.

Quickly use the brush to apply the kiln wash. Cover all areas that might come into contact with the glass. As with a spray application, the kiln wash will sizzle as it goes on. Once the stainless steel item is covered with kiln wash, allow it to dry completely and return to room temperature.   If you wish, you can return the mold to the still warm kiln to help it dry more quickly, or you can just let it air dry.

One application is often sufficient to cover the stainless steel item. If not, simply reheat and coat again. You may want to sand lightly between coats. Once the item is dry and room temperature cool, check to make sure that none of the air holes at the bottom have been filled with kiln wash and are in need of opening.

Some people rough up the surface of the mold prior to applying kiln wash to help it stick better. If you decide to do this, use very fine steel wool (000 works well) and make certain you wash the mold well before applying the kiln wash.

When you finish, the mold should be smooth to the touch, with no visible gaps or bumps. The kiln wash application should last for several firings, but if it flakes away, starts to look thin, or discolors slightly, you should reapply the kiln wash. For best results, lightly sand the mold with very fine steel wool before reapplying.

Many thanks to the Warm Glass website for posting this important information.  Click here to read the Warm Glass website!

Preparing a kiln for glass

by Glass Fusing Made Easy
http://www.glass-fusing-made-easy.com/


Before you begin any project you must go through the preparing stages. The first time you fire the kiln it must be made ready for this and any future firings. This action only needs to be done once, as the kiln wash will last for a few years.

Other items that must go through a preparation stage would be the kiln shelf and any molds that you might be wanting to use. These items need to have kiln wash applied more often than the kiln. When you see that the wash is beginning to flake or wear off then scrap off the old wash and start with a new coating.

Preparing Kiln

Preparing your kiln for its first firing takes a little time. The floor and lid need protection. This protection is to prevent glass from sticking to this surface if it should come in contact with it during any firing. First vacuum the kiln, to remove loose dirt or dust from the floor. Be sure you don't bump the thermocouple or mess up the fire wall bricks. The fire wall bricks are soft and they make up the floor, sides and top of your kiln.

Now that your kiln is clean, you will need to apply kiln wash to the floor. If any pieces of glass should happen to fall on the floor of your kiln, you don't want it to become stuck and damage the fire bricks. You can make your own homemade kiln wash.

Be sure to read and follow the manufacturer's directions in mixing and applying the wash. When mixing kiln wash, be sure to wear a mask, because the dry powder can be harmful if inhaled. Mix in a glass jar with an air tight lid. You won't be using it all, and it can be shaken up and used later. This mixture can be poured into a bowl for easier application, being sure to shake or mix before pouring. It should be watery in consistency.

Use a haik brush, wide paint brush, or foam paint brush if surface is cool to the touch. The haik brush is soft and leaves a smoother finish.

Go in one direction only. Then apply another layer in a 90 degree angle from the previous application. You need to apply about five to six coats in this manner.

Plug in your kiln and heat it to approximately 500 degrees. This will evaporate the water in the kiln wash. Be sure that you vent the kiln lid with a kiln post or fire brick. Shut the kiln off and unplug. It will cool off and the kiln wash will be a powdery substance.

Check to see that you have a covered smooth layer. You can use an old pair of pantyhose to smooth the layer.

You could use a sprayer, but there is a chance of spraying kiln wash on the kiln elements. To eliminate this problem use a haik brush. 

Preparing Kiln Shelf

Preparing your kiln shelf is easy. You can protect your shelf with kiln wash, fiber paper, thin shelf paper, or lava cloth. You only need to use one type of protection.

Apply kiln wash to your kiln shelf, just as you did for the inside of the kiln. Be sure not to open your lid to wide, or you might crack the shelf.

Fiber paper can be cut with scissors to the size and shape of the shelf. You need to pre-fire this fiber to approximately 1200 degrees. This pre-firing will burn the binder out of the fabric. Be sure to vent your kiln during the process. It will give off a sweet smell and even some smoke. The smoke is not harmful, but can be a little distasteful. Once pre-fired, it is now ready and can be used in your fusing projects. Allow the paper to cool before removing. It can be used over and over again, unless ripped or soiled.

Thin shelf paper is a one time single firing paper. It is designed to protect your shelf for a single firing only. It can easily be cut with scissors to fit the size of your shelf. There is no pre-firing of this paper. When you are through firing, this paper will be nothing but ash on your shelf. Use caution when removing it, and wear your dust mask.

Lava cloth is great for adding a unique texture to your glass. It does not stick to glass, kiln shelves, kiln brick, or fiber board. It will also last through many firings, but can be very expensive.

Preparing Molds

You will need to apply kiln wash to your mold before using. Apply just as you did for the kiln and kiln shelf.

Check the holes in the mold. They should be open for air to escape during slumping. If these air holes have been filled with wash, just poke the wash out of the hole with a wire or any other sharp object.

A little tip: molds can be heated in your home oven for drying.

Firing on the bottom of your kiln

by Glass Fusing Made Easy
http://www.glass-fusing-made-easy.com/


Firing on the kiln bottom, is sometimes necessary in smaller kilns. You might find the need to put something inside the kiln, but there is not enough room with the shelf inside. This is a common thing with the smaller kilns.

Newer kilns usually have an improved uniformity of heat distribution throughout the kiln. This guide is only meant as a starting point. You will need to rely on your own experience and that of others who have tried this process. 

Inside the kiln the hot air needs to move and circulate. As the kiln is heating up, warm air circulates through the kiln. The heated elements radiate direct heat onto the glass. As the hot air moves through the kiln it transfers heat around and under the glass. There might be some advantage to heat circulating beneath your mold, so be sure to place it on prepared kiln posts.

You will need to protect the bottom of the kiln. Use Kiln wash, fire blanket, fiber board or fiber paper to protect kiln bottom. You should always coat the firebrick bottom of your kiln with kiln wash, even if you are firing the glass on a shelf.

If using a shelf out of ½” fiber board, place it on the bottom of the kiln. Be sure to take it out when not being used to keep it from getting smashed or dented. Always check to see that your foundation is flat and level, and use a conservative firing schedule.

When and if you feel the need to fire a piece on the kiln bottom, I hope this information will come in handy and assist you in this process. As always take notes and refer to them when doing future firings.

Excellent video by CHRISTIANES GLASKUNST, hot glass art

This is such a fun video to watch!
http://www.youtube.com/watch?v=lS2lhRIAQ

* 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.

Kiln Secrets, getting to know the types of units, and what to purchase

by Glass Fusing Made Easy

http://www.glass-fusing-made-easy.com/

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.

Kiln slumping wine bottles and other glass bottles for glass art

I found a lot of info online about kiln slumping bottles, so to try something different today, I posted two excellent articles that I found.  Have you ever wondered about labels? Do you want to learn how to remove labels from your bottles or do you want to know how to keep labels on bottles when firing?  Well, I have also found some info on those subjects and posted it below.

Tutorial 1.

Warmglass.com http://www.warmglass.com/Bottles.htm  says:

Slumping bottles in a kiln is not difficult.  It does, however, require a knowledge of basic kiln-forming principles and an understanding of both thermal shock, annealing, and devitrification.  If you are not familiar with these terms, then spending a few moments with the Warm Glass tutorial will help familiarize you with the process of heating glass in a kiln.

The basic process for slumping a bottle in a kiln is as follows:1.  Clean the bottle thoroughly and allow it to dry.  Some people also apply a devit spray to the bottle to help prevent devitrification.  This is recommended for most blue and amber bottles and is also helpful for other colors as well.
2.  Cover your kiln shelf with either fiber paper or kiln wash.
3.  Lay the bottle in the kiln on it side.  It's not essential, but some people place a piece of wire in the neck to form a wire loop which can be used to hang the bottle after slumping. (20 gauge twisted copper works well.)
4.   Fire the kiln to 1100F and soak for 10 minutes.  The rate of temperature increase should be from around 500 degrees per hour.  Some people fire as fast as 800 degrees per hour, but be aware that the faster you fire the more likely the bottle is to crack from thermal shock.  The purpose of the 10 minute soak is to allow the temperature of the glass to equalize and to all reach 1100F.
5.  Fire the kiln at 250 degrees per hour to 1300F, then fire as fast as your kiln will go to 1475F.  Hold the temperature constant at 1475F until the bottle has slumped to the degree you want.  Usually this takes around 10 minutes.
6.  Cool the kiln to 1100F as fast as possible.  You may need to flash vent the kiln to speed cooling and to help prevent devitrification, but some people slump bottles with flash venting.
7.  Anneal.  Some people accomplish this by simply letting the closed kiln cool naturally.  This approach will work if your kiln cools slowly enough through the annealing range (for bottles, roughly 1050F to 850F).  You would want to cool at a rate of 150 degrees per hour or slower.  If your kiln has a controller, a proper anneal soak is highly recommended:  soak at 1030F for 20-30 min then 100 dph to around 850.
8.  Cool to room temperature.  Most kilns will cool at a slow enough rate to avoid thermal shocking the bottles by cooling too fast.

Tutorial 2.
http://www.bigceramicstore.com/information/Tip92.htm says:


Bottle slumping is becoming quite popular, probably because you don't have to buy special glass, you just re-use wine and beer bottles.  (Make sure you recruit your friends to help you drink all that alcohol!  We know how it feels to look at a really cool Grey Goose vodka bottle and think "How long will it take me to empty that?"  Given how addicting this is, we wouldn't want to be responsible for any irresponsible drinking!)

Basic requirements:
You will need a kiln that is able to fire to approximately 1500 degrees For higher.  Any ceramic kiln or glass kiln can be used for this, as long as the bottles fit.  Unfortunately the long shape of bottles make them hard to fit in many kilns.  So we designed the Trio Kiln specifically to fit all our bottle slumping molds.

You need some type of separator between glass and what it sits on.  (The shelf or mold,)  Options are glass separator, Mold-EZ or Primo Primer, which are brushed on, or thin-fire or fiber paper.

You will need glass bottles, such as wine bottles, beer bottles, soda bottles, etc.  Wine bottles make nice trays and dishes, beer and soda bottles make great spoon rests.

Molds are an option that can be used to shape slumped bottles into dishes and spoon rests, or you can simply slump bottles flat, directly on the shelf to make trays.


With all slumping, there are general principles that need to be followed:

Bottles must be clean and dry.  All label residue must be removed.  Some people will use isopropyl alcohol to clean any fingerprints from the glass as well.  The best label removal process I have used to date is filling the bottles with very hot water, and placing them in a bucket filled with very hot water and powdered oxy-clean.  Let that soak a couple hours to over-night. Most labels drop off or can be scraped off with a plastic scraper.  I often use those handy fake credit-cards that come in the mail.  Ah, yet more recycling!


Bottles need to be placed on a surface that has been kiln washed or shelf paper such as thin-fire paper can be used.  This is to prevent the glass from fusing to the shelf.  When using kiln wash, be sure the surface is very smooth.  Any brush strokes, bumps, etc. will show up in the glass.  Even seams between sheets of thin-fire paper will show.
If slumping bottles with "painted" labels such as Corona bottles or Belvedere bottles, those labels remain on the bottle even after slumping.  The trick is to have the bottle remain in place during the firing.  Otherwise, the label looks off-center.  I have used small pieces of thin-fire paper to prop a bottle that wants to roll.  Granted these can be seen on the back of the glass, but in my mind that is better than tossing a bottle because the label looks funny.
If using a mold, it should be covered with a thick coat of kiln wash or glass separator.  We offer a variety of mold shapes for slumping bottles. You can also make your own shapes using your own bisque.   I often use smaller triangle shelf posts wrapped in thin-fire paper to create an elevated neck on beer bottles for spoon rests.  They are small enough to allow the top of the bottle to touch the shelf after slumping. Sometimes glass will get de-vitrify, or get cloudy.  This seems very dependent on the glass the specific bottle was made from.  But we have found that cleaning the bottle really well helps avoid it.  We also have Super Spray, a de-vitrification spray which can be used.

One other thing to consider before firing is whether you plan to hang the tray or spoon rest.  I have found high temp. wire works well and does not break down.  Copper and brass wires will break down a bit, sometimes leaving unattractive flecks in the neck of the bottle.  Simply cut a piece of wire, shape, and place in the opening of the bottle. As the neck slumps, it will permanently fuse the wire into place.  If I want the wire to be gold, I just paint it later.

Decorating your slumped bottles can be a lot of fun too.  You are the artist!  Anything is possible.  You can paint on them with Hues2Fuse non-toxic glass paints prior to firing.  You can fire the bottles on texture molds.  Some people incorporate other pieces of glass, such as marbles, although this can be tricky.  And many people use wire (such as copper) to decorate them after firing.
FIRING PROFILES
As you research slumping bottles, you will learn there are many different firing profiles out there.  Some profiles are provided specifically from the kiln manufacturers, others are a blend of several firing profiles from other artists.  My own profile is a combination of both.  I use a 7cu. electronic controlled kiln and primarily flatten bottles for cheese trays and spoon rests.  The slumping profile that came from the manufacturer did not seem to adequately slump all of the bottles.  Whether the uneven slumping was due the location in the kiln, the type of glass, the size of bottle, the variety of bottles in a single load, or the number of shelves I loaded, I cannot be certain.  Aside from still trying to eradicate a few small bubbles trapped in the body of the bottle, I have had pretty good success.  Generally the firing takes approximately 9 hrs.

Segment	Rate	degrees F	Hold
1	500	500	12 min
2	500	750	12 min
3	600	1100	10 min
4	200	1300	20 min
5	250	1475	10 min	takes roughly 4.5 hrs to this point
6	9999	1100	1 hr
7	500	970	30 min	annealing occurs between 800-1000 deg.
8	120	750	20
Let kiln cool naturally.

To give you an idea about different firing profiles, we have also been using this profile for wine bottles, with success, in the Trio Kiln.

Segment	Rate	degrees F	Hold
1	500	1100	10 min
2	250	1300	0 min
3	300	1425	10 min	at first we had this at 1475 but the edges of the bottle were sharp
Let kiln cool naturally.

This profile does not even have an annealing phase, but we have found it seems to work fine.  If you choose to use this profile, you may consider adding an annealing phase at the end.

Keep in mind these are guidelines, as every kiln will fire a little differently.  It will take a few firings in your own kiln to obtain the results you desire.  Be sure to keep a log so that once you have a successful load, you can duplicate it.  And most importantly have fun with it.

Wishing you the best of luck! - Kris
copyright 2010 BigCeramicStore.com

Check out BigCeramicStore.com to purchase a variety of bottle molds and supplies!


Tutorial 3.

SAVE THAT LABEL!

by http://www.beekmanwine.com/prevtopr.htm

We all know how frustrating it can be trying to remove some labels from wine bottles. Removing labels used to be quite simple, but new glues have been developed to prevent labels from coming off in restaurant wine buckets. These glues make it difficult to remove the labels at all, but one of the following methods will almost always work.


Several different glues are used today and you can’t tell which one was used by looking at the label. No single technique works every time on every label, but there are some relatively safe bets. First try to peel the label off starting in a corner. If you are lucky and the winery used the new “peel and stick” type of label, the label will come right off (However, it will immediately stick to anything it comes in contact with!). Most times you will not be so lucky.


The Blow-drier Method - Some of the new glues are unaffected by water, but will melt enough to slide the label off the bottle after “toasting” the label with a blow-drier for about 5 minutes. A heat gun will work faster.


The Tape Method - This method separates the layer of the label with the image on it from the layer with the glue. 

We sell a product called Labeloff Label Saver ($8.95) which works 98% of the time. It's a package of clear plastic sheets with an aggresive glue on one side. You must follow the instructions carefully.
Or you can contact the manufacturer directly:
Pentad Group, Inc.
106 Pentad Plaza
1446 N.W. 2nd Ave.
Boca Raton, FL  33432
(561) 362-8678
e-mail: labelsaver@aol.com

You can also do it yourself. Go to any office supply store and buy a roll of clear 3” wide strapping (packing) tape.
1. Cut off two strips of tape that are about 4” wider than the label.
2. Fill the bottle with VERY hot water (trying not to get the label wet). Wipe the bottle dry.
3. Put a strip of paper about 1/2” wide across the sticky side of both ends of the tape so the ends won’t stick to the bottle.
4. Working from one side of the bottle to the other, attach the tape to the bottle so that it just extends (about 1/4”) above the label. Bring the tape across the label, using some type of straight edge to smooth it out as you go.
5. Once you have the first strip in place, if it doesn’t fully cover the label, attach the second strip right under the first.
6. Use the back of a spoon to rub hard all over the label.
7. Starting at one edge, slowly start to peel off the tape.
8. Once the label is removed, trim the edges with a scissors.

The Soaking Method - this is becoming less effective as fewer water-soluble glues are being used.
Equipment: 1 tall Igloo water jug (the picnic kind), tall enough to hold a bottle, Ivory Detergent, paper towels, wax paper, a single edged razor blade, a heavy book, a cork, and a glass of wine.
1. Fill the jug with warm water and 2-3 drops of Ivory Detergent.
2. Fill the wine bottle itself with VERY hot water and immerse it in the jug.
3. After about 30 minutes, the label should either be floating in the jug or loosely clinging to the bottle. If not, continue the soak for 2 hours or overnight.
4. If the label still isn’t off, take the bottle out of the jug and fill it again with very warm water. Cram an old cork into the top and dry the bottle well. Get the label as dry as possible.
5. Lay the bottle on a towel to steady it. Use the single edged razor blade to scrape the label off. Start working from the left side of the label, following the curve of the bottle, to about the middle of the label. Then start from the right side of the label and cut back to the center. Work back and forth until the label is off.
6. Put the label between towels to blot of as much moisture as possible. Be careful! Some of the new glues are of the “peel and stick” variety and will stick to anything. If you find one of these, press the label down on some plain white paper and trim around the label.
7. Place the label on a piece of waxed paper with paper towels on top of it and weight it down with a heavy book until the label dries.
8. The glass of wine? You know what that’s for!


Joel’s Method - Forget the darned label and buy another bottle! 

Tutorial 4.

You can fire some labels, by Harrach glass

If you have a bottle that has a baked on enamel paint for the label the enamel will stay on the bottle as seen in the photo. Some enamels will change color or fade. If the bottle has etching the etching will soften. Some bottles get a soft haze that can not be helped.

Kiln-pressed glass (a process that makes kiln glass look like it was mouth blown) no photos available

Are you tired of typical, two and three layer fully fused glass art?

Have you have ever wished you could create the watercolor-like effects that are typical in blown glass – but seem impossible to achieve in fused glass?

If so, this unusual and original glass fusing tutorial is for you.

The technique is one we call “kiln-pressed glass” and it is something we’ve developed at Helios over the past year.  We doubt we’re the first to do what we describe, but we’ve never seen it discussed elsewhere and we are pretty sure that nobody else has documented and shared the technique before now.

Kiln-pressed glass is so full of potential that we want to share it so that we can see what others are able to create with it.   Here’s just one example of what’s possible.   It is the piece that we create with the tutorial:

To help you fully appreciate kiln-pressed glass, we’ll start with a brief review of how glass melts and why it is difficult to create thin fused glass objects.

Surface Tension

All liquids have surface tension – the attraction between molecules that, on the surface of a liquid, causes the liquid to behave as if it had a thin skin.  Surface tension, for example, is why water drops on a slick surface will “bead” up.

Surface tension strength is different for different liquids.  Mercury, for example, has very strong surface tension.  Acetone, in contrast, is very weak. The strength of the surface tension of glass at 1500° F is somewhere between the two.  The strength of the surface tension determines the natural height of the liquid when allowed to spread.

For glass at 1500° F, that height is about ¼ inch (6 mm) – which is the same height as two standard layers of glass.  Understanding how this impacts the results when fusing is one of the most important lessons a fused glass artists can learn:

• If your project has less glass than in two complete layers (for example, a single layer with only a few design elements), the edges of the base glass will begin to pull up as the glass tries to achieve the ¼ inch thickness.
• If your project has close to two complete layers (for example a single layer of  glass with a complete second layer of design elements), the glass will flatten when fully fused – but will maintain its overall shape.
• If you have more than two layers of glass, the glass will spread when fully fused (unless you contain it with dams)

Here’s a simple illustration showing the above three examples:

But what if you want a fully fused design – but you want it to be a single layer thick?

One solution is to fuse the thick project and then grind it down with coldworking equipment, such as a reciprocating lapidary grinder like this one:

That approach requires expensive equipment, a lot of time, and you end up wasting a lot of material by grinding it away.

With kiln-pressed glass, you probably already have everything you need, the work is all done in the kiln, and there is no wasted glass.

Curious how it works?  Just click the “Overcoming Surface Tension” link below and we’ll get started!

Overcoming Surface Tension

The basic idea behind kiln-pressed glass is that we can defeat the surface tension and create thin glass by squeezing it from above using weights.  The basic setup looks like this:

As shown, the glass is placed between two kiln shelves and weights are placed on top.  Small fiber strips placed in the corners act as spacers to prevent the glass from being pressed too thinly.

The concept is surprisingly simple but the results can be spectacular.

Setting Up the Glass

The setup for our project is includes a lot of clear glass and some strategically placed transparent colors.  One of the best parts about kiln-pressed glass is that transparent colors that often seem too dark to be useful in typical fused glass projects dilute to wonderful hues in kiln pressed glass.

When stacking your pieces of glass, make sure that there are three or more equal high points.  This ensures that the top kiln shelf is level when placed on the glass.

Although not required, the base piece of glass makes it easy to build your piece and move to the kiln.  It will also help you to achieve the smoothest possible surface after firing.  In this example, the base is about 6 inches across.

Place your setup on a freshly primed (kiln washed) shelf as shown:

Note the fiber paper strips that have been placed near the edge of the shelf.  The height of the fiber paper (once fired) will determine the thickness of your final piece.

We are now ready for the top shelf and weights.

Setting Up the Weights

Coat your second shelf with shelf primer and place it (primer down) on top of your glass as shown:

Make sure that the shelf is either below the thermocouple (the small metal rod that sticks out of the wall of your kiln) or, if it is above the thermocouple, that there is no chance of it hitting the thermocouple as the glass melts and the shelf moves down.

If you have stacked the glass as described, with there being at least three, equally tall stacks, the shelf should be level.

Now place your weights on top of the shelf.  Old pieces of kiln shelf, high density fire bricks and kiln furniture are all suitable.  Do not use stones!  Stones can contain water that expands when heated, causing the stone to explode.

Here’s our top shelf loaded with weights:

We are ready to go!

Close the kiln and fire as explained on the next page.

Firing

Here is our firing schedule for our kiln-pressed glass:

Segment	Ramp	Target	Hold
1	300° F / hr	1225° F	3 hours
2	FULL	1500° F	1.5 hours
3	FULL	900° F	2 hours
4	100° F / hr	700° F	none

The long hold at 1225° F allows the glass to compress, eliminating much of the trapped air and helping the shelf to stay level as it drops.

The long (90 minute) fuse ensures that the glass is fully pressed so that the shelf rests on the fiber spacers.

Our annealing (from 900° F to 700° F) is fairly aggressive – that’s because our glass is exceptionally thin so there is little reason to be worried about heat differentials.

After 700° F, we can let the kiln cool naturally.  Thanks to all the extra mass provided by the weights, cooling will be very slow.  You can vent the kiln at 500° F and open it fully at 300° F without worrying about thermal shocking the glass (again – because it is so thin).  At 200° F, remove all the weights and shelf to allow the piece to finish cooling.  Be careful when taking out the weights – they will often be hotter than the ambient temperature of the kiln.

With the weights and top shelf removed, you should see something like this:

Congratulations!  You’ve completed your first kiln-pressed glass or follow this next step for more effect!

Adding More Glass

We don’t have to stop with a single pressing.  With additional glass and pressings the results can get pretty spectacular.

Here’s our setup for the second pressing.  Note that we have sandblasted the surface of our first results to ensure we’ve removed any residual kiln wash.

Here’s a close-up:

In addition to more color, we’ve also made careful choices about adding some clear pieces to the mix.  The clear glass will cause the color glass to spread more, thinning it out, and diluting the color.  Using clear glass this way can provide wonderfully subtle color variation and create vibrant watercolor effects.

We repeat the same setup and firing schedule as with our first pressing, slump the piece over a handkerchief mold for the results shown on the next page.

Finished Project and Tips

Kiln-pressed glass has endless possibilities and produces work unlike most of what is being created by fused glass artists today. 

To help you on your way, here are some tips:

Glass reactions (the color changes that occur when certain glasses are fused together) tend to be intense in kiln-pressed glass.  You can avoid this by placing clear glass between the reactive colors.  You can see this in the finished piece above – reds, yellows, greens and blues all overlap without creating browns that would typically occur when mixing these colors.

As mentioned in the article above, many of the transparent colors available today are very saturated and appear almost black without a light behind them.  When thinned during in a kiln-pressed glass project, these same colors often produce gorgeous hues.

Pay attention to how glass spreads when pressed – usually from the center out to the edge.  With practice, you can be increasingly deliberate with your design.

Use a scale to determine how much glass you are going to press.  If you use too much glass, it will squeeze out from under the top shelf.  One square inch of a single layer of fusible glass weighs about 0.2 ounces (5.5 grams).  You can use this value to determine how much glass is needed for a given size – or, you can simply use our Pot Drop Calculator to do the work for you.

Thank you Helios Glass for sharing this great tutorial for Kiln-pressed glass on Fusedglass.org http://fusedglass.org/learn/project_tutorials/kiln_pressed_glass_finished_piece_and_tips  We can't wait to try it!