Firing a bottle with an enamel label, tutorial

Once you start putting glass bottles in your kiln you will quickly learn these techniques.  When you are just starting out you will want to look online for this information but you probably won't find it written in many articles.  So today we thought we'd share some of our own Harrach Glass,  glass bottle firing techniques with our readers.

Basically what you will need to remember is that the part of the bottle that is laying on your kiln shelf will look dull after being fired.  So if you want an enameled label to look shiny, make sure it is facing upwards on your kiln shelf or in a mold.

Next, if the bottle not only has an enameled label on the top side, but also has writing on the bottom side that you want to preserve (even though it will look dull), you need to lay the bottle on shelf paper instead of laying it on a primed shelf or mold.  Usually the enamel writing or image will stick to shelf primer but it doesn't stick to shelf paper.  It is also advised to use shelf paper that doesn't have a texture since that will show after fusing.  Just lay shelf paper on the mold you intend to use and the enamel will not stick.

Always use devitrification spray on your bottles.  We just wipe it on to the entire bottle, by hand!  Click here to see the our link to homemade Devit Spray, that works every time!  You don't need to let the spray dry before turning on your kiln either.

Firing contours

When you are looking for kiln firing schedules, you will always find these three different types of schedules in books or online.  Most glass manufacturers have their own temperature ranges to follow to achieve these three contours, so it's best to check with each individual manufacturer.  Don't forget to take firing notes to keep track of what works best for you and your kiln.  

Now when you are new to fusing, you might be confused as to the difference between tack fusing, contour fusing and full fusing.  We thought we'd write a little about these three different techniques today.

Tack Fuse 1350º- 1370º

Contour Fuse 1400º-1450º

Full Fuse 1460º- 1480º

The tack fuse contour comes in handy when making pendants or other glass art where you want multiple layers to look as though they are only laying on top of others.  It can look nice when done with dichroic glass tack fused on top of a non dichroic base glass.  Also when you need to lightly fuse multiple elements together, without melting down (and melting together) the entire piece, you will want to use a tack fuse schedule.  If you have a piece that will need many firings and you want all pieces to keep their original shape when completed, it helps to tack fuse the pieces until the last firing.  Remember, the thicker the piece you want to fuse, the slower you need to heat up the piece until you get to the final heat desired!

The contour fuse is a more rounded off version of the tack fuse.  The edges are not squared like what happens when tack fusing.  

A full fuse completely melts down multiple layers of glass so that the piece looks flat and seamless.  When making pieces like dishes and bowls, etc. that have multiple design elements placed side by side, typically laying on top of one piece of base glass, you should full fuse the piece first before slumping into the mold you intend to use.

Finally, a little info about slumping glass into or over a mold.  It is possible to slump and fuse a piece at the same time.  If a piece has a lot of design elements, some of which could possibly move when slumping, it is best to fuse first before slumping.  To slump you will need to heat your kiln up to between 1200 and 1300 degrees Fahrenheit.

Firing schedules for thick pieces of glass

It is very important to get the correct firing temperature for your glass projects so that you don't open your kiln, thinking your project is completed, only to discover a broken disaster!  In our own glass studio, we have discovered, the hard way, that we have to slow down our firing schedule when fusing our glass bottles together.  You will find that you not only need to slow down the heating up process, but also the cooling down part too.

We found these great tables below, made by System 96 glass.

*Please note: the schedules below are guidelines only, not strict rules. Times and temperatures may be adjusted based on the nature of your project. To use these schedules for slumping, set the target temperature in the "variable" step to 1235 - 1250 depending on your desired results.

1/2 -inch Thick Step Rate(per hour) Target Temp. Hold(minutes) 1 100 300 15 2 250 1050 10 3 *variable 1500 desired effect 4 as fast as possible 950 90 5 100 800 10 6 300 100 0

*This rate varies based on what you want to accomplish. For instance, heat faster to fire polish, slower to minimize air bubbles.

1 -inch Thick Step Rate (per hour) Target Temp. Hold(minutes) 1 100 300 15 2 200 600 15 3 300 1050 15 4 *variable 1500 desired effect 5 as fast as possible 950 120 6 30 800 15 7 50 700 10 8 250 100 0

*This rate varies based on what you want to accomplish. For instance, heat faster to fire polish, slower to minimize air bubbles.

1.5 -inch Thick Step Rate (per hour) Target Temp. Hold(minutes) 1 100 300 25 2 200 600 25 3 300 1050 20 4 *variable 1500 desired effect 5 as fast as possible 950 180 6 12 800 15 7 24 700 10 8 120 100 0

*This rate varies based on what you want to accomplish. For instance, heat faster to fire polish, slower to minimize air bubbles.

2 -inch Thick Step Rate (per hour) Target Temp. Hold(minutes) 1 100 300 40 2 200 600 40 3 300 1050 30 4 *variable 1500 desired effect 5 as fast as possible 950 240 6 8 800 30 7 16 700 30 8 65 100 0

Using a steel floral former mold

We really loved these pictures of a glass piece in various stages of slumping that the Clearwater Glass Studio posted on their webpage!  Please check out their webpage for more great tutorials. Click here to view their webpage!

Initial kiln setup. A glass square is first fully fused and cooled, and any coldworking of the edge that is needed is done at this time, It is then placed in the kiln for slumping. In this example the glass is 1/4" thick, and placed shiny side up.

(This is actually a different piece then in the photos below.)

You have to watch carefully while you do this. Find a temperature where the glass just starts to droop, such as 1050F and hold for 15 min. Keep adding temperature in 50 F increments, until you see movement. Then, hold it there, and keep checking until it has folded to the degree you want.

The specific temperature needed will depend on the type of glass, the color, the size and thickness, distance from the elements, and the particular kiln.

I don't remember what temperature I used in thistutorial, but with Bullseye glass, I'd start at 1050-1100F.

Note how glass slumps and folds during the heating process

Make sure to stop the slumping process before the tips of the glass touch the kiln shelf or they will flatten out and lose their gloss.

Example of a finished vase.

Making Wine Bottle Cheese Plates in Your Kiln.

Slumping is HOT!

After enjoying a little fruit of the vine....The first thing you'll want to do is remove the label from your bottle; for stubborn ones Goo-Gone works well.

Next be sure to wash and dry your bottle completely. Moisture is the enemy. It can cause the bottle to explode in your kiln, making a very big mess.

Bottles with painted labels are ok (actually - they are trey cool ;) but I suggest using a thin sheet of fiber paper under the part where the label comes in contact with the molds surface, otherwise the bottle might get stuck and ruin your mold. YUCK! see the picture below.

Devitrification spray can be applied to the bottles to prevent a hazy or a scummy appearance on the glass after it's fired. (I don't bother with this).

If you would like to hang your bottle for decorative purposes; take a piece of 20 gage copper wire (or fine silver) shape in a U and insert it in the bottle top before slumping.

Use a clay mold that has been pre treated with glass separator. Separator should be reapplied between firings and dried completely, as needed. Check the tiny vent holes, in the mold - under the glass, to be sure that they are not plugged with the separator.

My Firing Schedule for med. to lg. bottle:

•1. 600 Degrees Per Hour to 1000 Degrees Fahrenheit, soak (hold temp constant) for 10 minutes

•2. It is only safe to peek* into the kiln from 1000 degrees and up- otherwise you will shock your glass and it will crack.

*Please protect your hands and arms with heavy kiln gloves and your face and eyes with tinted safety glasses!

•3. Heat AFAP (as fast as possible), to 1375 to 1425 DF, (depending on the size and thickness of your bottle)

•4. Soak (hold temp constant) for 5-15 minutes or until the bottle is slumped to perfection.

•5. Watch it closely during this time it can move rather fast!

•6. Allow the Kiln to cool until the temperature falls to 1000 DF.

•7. Soak for 10 minutes at 1000 DF.

•8. Annealing Stage; slow cool at 180 DPH to 800 DF.

•9. Next turn off the kiln and let it cool naturally to room temperature; don't peek*! (see #2 above)

After you remove your project from the kiln; be sure to vacuum any spall that comes off the copper wire to avoid contaminating your next project.

You may want to adjust the temperature and/or soak time according to the size and thickness of your bottle.

Practice is the best teacher and sometimes an error is the result of what will be some of your favorite pieces.

Most importantly, have Fun!

Bottles from my Kiln

Snowman Cheese Ball

Belvedere Bottle

Bottle stuck to the mold...YUCK!

Hot Glass in the Kiln

This interesting tutorial was written by:

shetrick on HubPages

While Sue Hetrick received most of her formal training in art from HACC, Central Pa’s Community College; she continues to learn from her own experimentation. Her ceramic pieces are crafted to be functional works of whimsy. The same can be said for her glass fused and slumped pieces, which tend to be her favored creations. The addition of wire wrapping make the glass pieces uniquely her own. Whether ceramic or glass, Sue crafts works of art that incorporate fun into function.

A few of our glass recycling experiments

Large recycled jar.... now it's a candy jar by Harrach Glass

Another large recycled jar by Harrach Glass, the perfect size for holding M & M's?

Paper weight by Harrach Glass, once was a smaller glass jar

As you can see we've been having fun lately slumping glass jars in our kiln.  Now we have a growing wine bottle and glass jar collection in our studio waiting for the kiln.  

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!