Hadar's Blog

This is long due, but I have finally been able to do what many of you have asked for: create a Compatibility Chart reflecting which metal clays can be fired in one piece, in one firing, and at what schedule. The chart also shows which metals can be fired together in more than one firing. Please download the file from the right-hand pane of the blog.

This chart goes hand in hand with the file “Firing Schedules for Hadar’s Clay™ – Quick Reference Table”. This file has just been updated and includes firing schedules for Quick-fire copper, bronze, White Bronze, steel, and Pearl Grey Steel.

The expanded instruction manuals for all of these clays have also been updated. The Instruction Manual for Hadar’s Clay™ – Quick-fire Copper and Quick-fire Bronze in particular, includes instructions on how to make the firing box, what carbon to use, how to position the pieces and the box in the kiln, etc.

I hope you find it helpful.

One important update is how to fire together copper and White Bronze, or copper, bronze, and White Bronze. This does not require a special kind of copper powder and can be done with the existing Quick-fire copper.

I am still trying to shorten this firing schedule, but what works so far is firing the mixed metal together, repeating the firing schedule for White Bronze (i.e., firing twice in succession according to that schedule), with two hours hold time in each firing instead of three.

Sometimes the copper and the White Bronze react and create a third bronze color, as you can see in the photo. This may eliminate the need to include bronze in order to achieve the three colors in one piece.

The combination of copper and White Bronze has a beautiful effect when it is applied in caning and mokume-gane techniques. These are techniques that I am exploring at present and have already presented in my workshops in Europe. They are also the topic of many workshops scheduled for this year and next.

Pearl Grey Steel is now available for sale from my online store.

The instruction manual is posted in the right-hand pane of this blog, along with the other manuals, as well as on the product page within the online store, linked above.

How is Pearl Grey Steel different from the regular steel clay?

The Pearl Grey Steel metal powder is silver-gray in color. It is very pliable and soft, and does not become grainy after being stored in the refrigerator, even after many weeks. It also leaves your hands clean.

The firing is done in one phase. The firing temperature is the same, but the ramp is slower. The firing requires holding at 1000°F/538°C for between 30 minutes and 1 hour before continuing to the sintering temperature. Firing time is less than 4 hours.

The fired clay lends itself to sanding and smoothing, which results in a pearl-gray color. Like White Bronze, it is not flexible and should not be bent or hammered.

Pearl Grey Steel is compatible with copper, bronze, and White Bronze. It can be fired with copper in the same piece. Sometimes a bronze-color halo is created at the border between the two metals, as shown in the photo above.

To combine Pearl Grey Steel with bronze and White Bronze, the steel has to be fired first.

To see more photos of Pearl Grey Steel jewelry, please see this posting.

I hope you enjoy it.

The file “Hadar’s Travel-teaching Schedule,” available on the right-hand pane of this blog, has been updated.

First, a correction: The workshop in Rochester, NY, is actually two workshops, back-to-back: September 30-October 1, and October 1-2. The workshops take place at Studio 34 Creative Arts Center and Gallyer. You can take one or both workshops, since there is a lot of material to be covered. Recently developed techniques of “caning” and “mokume-gane” in metal clay will be presented. If you read this posting through, you can see photos of pieces made using these techniques.

A workshop has been added to this year’s schedule, on November 15-16 at Amado Territory Ranch, 30 miles south of Tucson, Arizona. Please contact www.exPRESSiveArtsStudio.com. This workshop will be entirely dedicated to “caning” and “mokume-gane” techniques, and on applying them to hollow forms. Some firing may be done for demonstration, but the class will focus on learning as many of these techniques as possible. Students will be expected to arrange for their own firing after the workshop. At this workshop I hope to meet up once again with students who took my workshop in Phoenix. The Amado Territory Ranch workshop is, in a way, a further step toward more advanced techniques.

So is a very similar advanced workshop that will take place in Los Angeles in February 2011, probably on Presidents’ Day weekend. It will take place again with the Local PMC Guild chapter. I will post the dates and contact information soon.

Another such advanced workshop will take place at Brighton Beads, Brighton, MI, on June 15-16, 2011. Immediately after this workshop, on June 18-19, I will be teaching In Saint Joseph, MI, at Krasl Art Center. This workshop will focus on making hollow forms and, for people who take the class at Brighton Beads, the application of caning and “mokume-gane” designs to hollow forms.

About the Structure of the New Workshops

In the course of nearly a year of intense travel-teaching I have been firing in many types of kilns. I won’t bore you with the details, but I have learned that no kiln is predictable and there is no way to guarantee firing results without testing individual kilns. These workshops are usually big, and many kilns are required. Based on all of this, I’ve decided that for workshops that are added now and in the future, I will fire only for demonstration purposes, and will dedicate most of the time to teaching more techniques and making more pieces. You can fire your pieces, or have them fired for you, after the workshop. This will make it possible for me to devote my attention to you rather than to loading, watching, and unloading kilns.

Unless I am asked to make changes, workshops that have already been scheduled will be conducted as advertised.

“Caning” and “Mokume-gane”

Why the quotation marks? Because the techniques I apply produce a similar effect to those of caning and mokume-gane as they are used in metalsmithing, polymer clay, and glass millefiori, but are not necessarily produced using the same methods as in those mediums. I must thank here Jen Tattam for planting the idea for these techniques in my head while experimenting at a workshop in Australia.

Two photos of these techniques were included in a previous posting. Those were made with three metals – copper, bronze, and White Bronze. Here are some more with copper and bronze:

It may be too early to get all excited, but this experiment has worked a few times now. I was surprised enough to discover that bronze and white bronze can be fired at the same time. I wasn’t too excited, though, since the contrast is not so sharp, and patina doesn’t make it any sharper.

So, I tried to fire all three metals together, copper, bronze, and White Bronze, with very little hope. I could not believe that copper could sinter at such a low temperature. Here are my results:

The center panels in these earrings are a combination of copper and White Bronze only.

This one is a two-sided hollow form (lentil).

The firing temperature is the same as for White Bronze. I am not sure yet how long the firing should be, what the size and thickness limitations are, and how way the metals should be combined. I am almost sure the latter is an important factor.

The funny thing is that a test piece, all copper, sintered just fine.

My first book The Handbook of Metal Clay: Textures and Forms is now out of print. This book has been well received, and sold out pretty fast. It received good reviews — one reviewer even asked me never to stop printing it. However, instead of re-printing it as is, I’ve decided to revise and update it, to accommodate the changes that have taken place in the past 3 years.

I would love to include work that you have done that was inspired by the projects in this book. If you are interested, please send or email me high-resolution photos. As with my second and third book, I can’t promise that the photos will be included; it depends on the quality of the photo and the space available. The artwork can be in other metal clays, not just silver.

There is no deadline. I will publish the book as soon as soon as I finish revising, so please please don’t wait too long.

My travel-teaching schedule has been updated. You can download it from the right-hand pane of this blog. New workshops have been added in 2011 in Pittsburgh, PA, Cleveland, OH, and Brighton and St. Joseph, MI.

I have just come back from a workshop in Texas and am preparing for a 3-week teaching trip to Europe. I will be teaching in the UK, France, and Norway. The store will stay open during this time and you will be well taken care of.

The rest of this year I will be teaching in Seattle, WA (August), The Netherlands (September), and Rochester, NY (October).

The participants of the workshop in the UK, hosted by Tracey Spurgin in East Yorkshire, will have the first chance (except for my local students) to experiment with Pearl-grey steel clay, which I hope to release after my return from Europe. This is a new type of steel clay, gray in the state of clay and pearl-gray in the state of metal. Unlike my traditional steel clay, it lasts a long time when stored in the refrigerator and does not turn grainy. It is as creamy and soft as the rest of my clays. After firing, it can be easily sanded smooth and brought to a matte finish. In reaction to patina it turns dark blue instead of hematite-black. It is compatible with all my other clays, and can be fired in combination with copper. The sintering temperature is 1750°F/955°C in a top loader, 1830°F/1000°C in a front loader.

Here are some photos:

The metals in the earrings above are (from top to bottom): Pearl-grey steel, bronze, regular steel, copper, and White Bronze.

Same metals here. The center bead is patinated blue.

Hollow rock earrings.

The earrings above are solid, but very light. They were not made with the same technique as published in my article "Mixed Metal Clay Earrings" in the last issue of The Jewelry Artist.

This pendant was fired with a gold nugget.

This is the same pendant with Birchwood Casey Super Blue patina (see instruction manual for steel clay).

The pieces in the three photos above were fired with no bronze in them. Where did the bronze come from? I am not sure, but I am very, very happy.

The pieces in the three photos above take advantage of the magnetic nature of steel. They are actually magnetic clasps.

After firing White Bronze almost every day since it launched, I have arrived at a new schedule that works for both thin and thick pieces. It involved a little surprise, but I’ll save that for later.

Here is the new schedule:

Ramp at full speed to: 500°F/260°C; No hold.
Ramp at 400°F/222°C to:
      1160°F/626°C (top loader kiln);
      1250°F/676°C (front loader kiln)
Hold for 3:00 hours

If you don’t want to deal with 2 ramps, use the following, simplified but longer schedule:

Ramp at 400°F/222°C per hour to:
      1160°F/626°C (top loader kiln)
      1250°F/676°C (front loader kiln)
Hold for 3:00 hours

Total firing time is 4:00 to 4:30 hours.

You will find programming instructions on page 4 of the White Bronze instruction manual. All of the manuals – for Quick-fire clays, for White Bronze alone, and the Quick reference guide – have been updated as of 5/4/2010. Please download the new versions.

The manual for steel clay will be updated with the upcoming launch of Pearl Grey Steel.

Now to the surprise. I had a little piece of Quick-fire bronze that needed re-firing. Having nothing to lose, I decided to add it to a batch of white bronze. The repair worked! I then fired pieces of bronze with White Bronze, using the above schedule for White Bronze, and all the bronze pieces fully sintered, although the firing temperature was lower by 300 degrees than what is required for bronze. It seems that at least in this case, slow ramping and longer hold time compensated for the lower temperature.

Furthermore, I included in this batch a mixed piece of bronze and White Bronze. Here it is, as it came out of the kiln:

And here it is after sanding and buffing:

Why is this good news? First, if you have just a few pieces of bronze and White Bronze, there is no need for separate firings.

Second, contrary to what I thought before, in order to combine bronze with White Bronze, it is not necessary to fire the bronze first; they can be fired together following the White Bronze schedule.

So, if you want to mix copper, bronze, and White Bronze in the same piece, you have two options:

1. Fire the copper first, then add bronze and White Bronze and fire again;
2. Fire the copper and bronze first, then add White Bronze and fire again.

I am currently testing combinations of copper and steel. Copper and steel, too, can be fired in the same batch with the same firing schedule. There is no need for separate firings.

Pearl Grey Steel and copper can be combined in the same piece, and the results are amazing!

I actually call this bracelet “The Sintering Bracelet” – not only because it has undergone sintering, but also because it graphically depicts the sintering process.

This posting has three parts: the tiles, the back of the tiles, and assembling the bracelet. This is an improvement on a bracelet project that is featured on my DVD, “Workshop at Textures Studio”. It is made out of White Bronze clay.

The Tiles

Use any design that appeals to you. Here is a pretty one taken from a rubber stamp.

Here is my sintering bracelet:

In the first tile from the left, the circles represent the particles of the metal powder in their “green” state. The spaces between them are filled with binder.

In the second tile from the left, the particles are getting closer to each other.

In the third tile from the left, the particles lose their spherical shape and fuse into each other.

In the fourth tile (the middle one), the metal is fully sintered. The particles got as close as they could to each other without reaching the melting point of the metal, and there are spherical pores between them.

The rest of the tiles show how the spaces between the particles change their shape. Starting from the right side of the bracelet:

The first tile from the right shows the shape of one pore between four spherical particles that hardly touch each other.

The second tile from the right shows the shape of the pore after the particles have fused a little.

The third tile from the left shows the spherical shape of the pore when the metal is fully sintered, as in the center tile.

The Back of the Tiles

1. Turn the tiles over and arrange them side by side. Mark two parallel lines along the whole row of tiles. Start from the smallest tile and adjust the rest accordingly.

2. Using a round miniature file, file a groove in each line.

3. Roll a layer of clay 2 cards thick. Pleace a tile on top of it and cut it on both sides to determine its width. Don’t cut the length yet.

4. Cut Angel Hair spaghetti into small pieces and place them in the grooves. The grooves help to hold them in place.

5. Wet the back of the tile.

6. Lay the strip that you cut in step 4 on the back of the tile. Make sure it adheres to the back at every spot. You can do this by rolling a straw over the layer, especially between the spaghetti straws.

7. Cut away the excess from the strip at the top and bottom of the tile. Dry. When the tiles are half dry, pull the spaghetti straws out by twisting them gently. Continue drying.

8. Seal all gaps between the two layers. Dry, and sand smooth.

This is a side view of the tile:

9. Fire the bracelet.

Assembling the Bracelet

This bracelet can be assembled using only Stretch Magic. For a different method of assembly please see instructions here.

Following the question I asked in my last posting, about firing at high altitudes, here is what I understand. The warming pans and the kilns were not overheating. The temperatures were correct. However, at higher altitudes, for plastic to melt, for water to boil, and for metal clay to sinter, lower temperatures are required.

Because of lower air pressure, the liquids in the clay evaporate faster than at sea level, and the gases trapped in it expand and escape faster.

So the higher the altitude is above sea level, the lower the sintering temperature will be, and the lower the altitude, the higher the sintering temperature.

Thanks to Gail, Kim, Peggy and Mary for their input.

Here is a project combining copper, bronze, and White Bronze clay. This project is hard to do with silver clay because of the reaction between silver and bronze.

This is a hollow form, constructed using the instructions for making a rock (see my first book, p. 69).

1. Choose a rock and cover it with a 2-card layer of bronze clay. Dry.

2. Cut the bronze layer in half and pull out the rock. Put the two halves back together and dry.

3. Cover the bronze hollow form with a layer of copper clay, 3 cards thick. Don’t dry yet.

4. Using a tube, cut a hole in the copper layer. Use a knife to cut a strip off the copper layer, continuing all around the rock. Now dry the rock.

5. Fill the round hole with bronze clay. Just “smoosh” it tight into the hole to make sure it touches the base bronze layer. It’s not important if you fill too much. Dry.

6. Use a sponge sanding pad to sand off the excess bronze, until the shape of the hole re-appears.

7. Position the rock the way you want it to hang. Drill a hole through the top third of it.

8. Fill the rock almost full with carbon. Fire it according to the instructions for your clay.

9. Clean the strip part using a radial disc or any other buffing/brushing tool. Fill it with White Bronze the same way you filled the hole. Dry.

10. Sand the excess White Bronze until the shape of the strip re-appears.

11. Fire the rock following the firing schedule for White Bronze.

12. Sand the whole rock smooth and flush.

13. Paint the rock with Baldwin’s patina to highlight the contrast between the metals. It will react with the copper, but not with the bronze and White Bronze. Wash the rock in warm water.

This is a question that I am often asked. The answer is that there is no absolute correct temperature. It depends on too many variables.

Some of these variables are: the type of kiln (brick or muffle), the location of the door and the heating elements, the size of the kiln, the age of the kiln, the carbon you use, the amount of carbon you use, the number of times you have used it, the box you fire in (steel, fiber blanket, ceramic, ceramic cloth, lava cloth, fiberglass cloth, etc.), the number of times you have fired in the same box, and finally, the altitude.

There is a simple way to figure out the right firing temperature for your kiln, which is trial and error.

Use bronze clay to make some test pieces, 3, 6, and 16 cards thick. If you have a muffle front loader kiln, fire them at 1550°F/843°C. If you have a brick kiln, fire at 1470°F/799°C. You can refer to my instruction manual for other conditions, such as box, carbon, and length of firing.

Take note of the firing conditions in which you did your test: carbon, box, etc.

After firing check the pieces. If they look curved, blistered, swollen, or somewhat textured, it means that this temperature is too high. Lower the temperature by 20°F (10°C) and repeat the test. Continue testing until you get smooth, strong test pieces.

To check sintering, use slight pressure to try to bend the thinner piece with your fingers. If it breaks, it means the temperature was too low. Raise the temperature by 20°F (10°C) and repeat the test.

A thicker piece may not break easily, even if it is not fully sintered. To check thicker pieces, sand the surface with course sandpaper. If the piece is not sintered, you will immediately see a non-metallic mass under the surface. Again, raise the temperature by 20°F (10°C) and repeat the firing until you get a strong, fully sintered piece.

Once you have found the correct temperature, try as much as possible to stick to the firing conditions you noted prior to your testing.

Next, look at the different schedules for the other clays, and adjust them accordingly. Now you have a customized firing schedule for your kiln.

Conditions may change, of course, so it is a good idea to test sintering after every firing. Buff or sand a hidden spot of the fired piece to see if there is non-metallic matter under the surface. If there is, you haven’t lost the piece. Just re-fire, or repair and re-fire.

I have just come back from teaching a workshop in Grand Junction, Colorado. It’s high desert, 4,700 feet above sea level. Two things happened that I had never encountered before.

First, the same candle warmers that I use in my studio (at sea level) were a lot hotter. They melted plastic, while at sea level I can dry a piece with a straw in it with no problem. Also, some of the kilns were firing too hot.

This seems somehow counter-intuitive, since from what I understand, because of lower air pressure, the higher the altitude, the longer it takes to heat; cooking rice takes longer, and baking bread requires adding dry ingredients.

Since this question may be relevant to metal clay users who live in high altitudes, I would appreciate any input on the subject that I can post on this blog.

The other thing that happened, was that Baldwin’s patina darkened the copper a lot more than I am used to seeing. This may be related to the composition of the air at higher altitudes, so again, if you happen to know the reason, I would love to hear it and let other people know.