Hadar’s Blog

One-fire Flex Rose Bronze and One-fire Flex White Bronze are now available on our online store.

One-fire Flex White Bronze, 6 cards thick, cut with an embossing folder and fired over a pre-fired circle of One-fire Rose Bronze.

One-fire Flex Rose Bronze circle, cut into a spiral, either by hand or with the Silhouette machine.

One-fire Flex Rose Bronze, experiments with folding and cutting paper techniques.

One-fire Rose Bronze, projects using the Silhouette machine.

My book, The Handbook of Metal Clay: Textures and Forms, is sold out. Again. I’ve decided to release the second, revised and expanded edition of the book as a CD, which is now available on my online store.

The CD is an exact replica of the second edition of the book. The projects are presented in PDF format, as are the title pages, Table of Contents, and Index. As a reminder, the third chapter of the book is about flexible clay, and all the projects included in this chapter can be done with our new One-fire Flex Clays.

Because of high demand for One-fire Flex White Satin, we are changing our release schedule and launching it right now. One-fire Flex White Satin Clay is now available on my online store.

As a reminder, White Satin is silver-color, high-fire clay, and fires in one phase only. It is strong, malleable, and does not contain any allergenic ingredients. It can be fired on its own and in combination with One-fire Copper, Dark Champagne Bronze, Low-shrinkage Steel XT and Pearl Grey Steel.

Here are some things I’ve done so far with One-fire White Satin Flex.

These earrings were made with an embossing folder. They are only 2 cards thick and survived aggressive hammering. Fired at 1680°F (brick) / 1730°F (muffle).

FYI, embossing folders work well with 6-cards thick flexible sheets!

This is an overlay of White Satin Flex on One-fire White Satin (not Flex, but could be). This was made with an embossing folder as well. The backing layer was blackened with gun patina. The piece was fired at 1680°F (brick) / 1730°F (muffle). This would work with a backing of Low-shrinkage Steel XT, Flex or not Flex.

This image of a sliced walnut was made with White Satin Flex, cut with the Silhouette machine, 4-cards thick. Fired at 1680°F (brick) / 1730°F (muffle).

And this walnut slice is textured, but not cut with the Silhouette machine.

White Satin Flex, made with an embossing folder, on top of One-fire Dark Champagne Bronze. Fired at 1750°F (brick) / 1800°F (muffle).

White Satin Flex, cut with the Silhouette machine, on top of One-fire Copper. Fired at 1750°F (brick) / 1800°F (muffle).

This one is all one solid layer which was not cut with the Silhouette machine, although the Silhouette machine “helped.” This technique is still being tested.

The following are experiments that I made with mixed metals. The first is just a funny shape, textured White Satin Flex, made with the experimental technique I mentioned above.

The second is a married metal piece, White Satin Flex and Copper Flex.

Because of the different shrinkage rates of White Satin and copper, some distortion occurred, but I was able to fix it with just a hammer. In the third piece I reversed the order, and placed the White Satin in the center.

This time some cracks occurred, since the White Satin shrank more and tried to stretch to the dimensions of the copper. However, repair was easy. This piece was cut with an embossing folder.

If you want to learn more about this married metal technique, you can read about it in my blog posting entitled “Married Metal – Free Project.” I will soon prepare a document showing what combinations of metal are possible and at what firing schedule.

It has come to my attention that some of you have been continuing to look for the instruction manuals, which I had removed from the right panel of this blog. All the instruction manuals can now be found directly on the product pages of my online store — the page for each Hadar’s Clay product includes a link to the instruction manual that applies to that product. For your convenience, though, I have now re-linked them from the right panel of the blog.

A new document has been uploaded and is linked here as well. It contains programming instructions for the One-fire Clays (including One-fire Flex Clays). The instructions are step-by-step, with photos. On the right side of each photo you will find an explanation of what that step means. At the end of the document is the full firing schedule for all the One-fire Clays in a single page, so you can print it out separately.

For those of you who are new to the One-fire Clays and to metal clay in general, I’d like to explain the rationale behind the firing schedule.

First Ramp

The kiln ramps at 1800°F. That means that it heats at a speed of 1800 degrees (Fahrenheit) per hour. (Bear in mind, it will not reach 1800 degrees; this is just the speed at which it will reach the desired temperature). In many kilns, 1800°F is the full speed.

First Hold temperature

When the kiln reaches 1000°F in a brick kiln, or 1100°F in a muffle kiln, it needs to stay at this temperature for a while. This is the temperature at which the binder burns, and it is the same for all clays! If the kiln were to keep heating rather than holding at this temperature, the binder would not be able to burn anymore because the reduction process would already have already began.

Reduction? That means that as the temperature rises above 1000°F (brick)/1100°F (muffle), less oxygen is now present in the kiln. With not enough oxygen, the binder cannot burn off. If the binder has not burned off yet, it will not burn at all, and that will end in poor sintering results. Failure to burn the binder is the most common cause for poor sintering. Some metals, bronze for example, will sinter well and be strong even if their final firing temperature is much lower than prescribed, but only if the binder has burnt off completely.

First Hold time

Hold time depends on how much binder you need to burn. The more pieces present in the kiln, or the larger they are, the longer you need to hold. Personally, I never had to hold more than two hours, and I do fire large pieces. For one small piece I would hold 0:30 minutes. For an average piece or just 2-3 pieces I would hold 1:00 hour.

Second Ramp

This ramp speed is the same as the first one. All we need now is to get to the sintering temperature.

Second hold Hold temperature

Now that that the binder is gone, the clay starts sintering. That means that the particles of the metal powder are getting closer and closer to each other until they cannot get any closer. This temperature is different from one clay to another and for each combination of clays. For some clays, like copper, if they are fired at a lower temperature than prescribed, they may still sinter, but will not be as strong as they can be. You can read more about this process in my blog posting entitled “The Sintering Project“.

Second Hold time

The second hold time is always 2:00 hours.

Questions:

Why do clays other than One-fire (like Quick-fire) not require hold time? The reason is that these clays are fired twice anyway, with a cooling phase between firings. That gives the binder enough time to burn off. These clays, by the way, will not sinter without cooling between the two firings, no matter how long you hold at 1000°F (brick)/1100°F (muffle).

Why is the the temperature different for brick and muffle kilns? Muffle kilns (usually front loading, white walls, with hidden heating elements), fire 50°F lower than brick kilns, probably due to a difference in heat distribution. In those kilns it is also recommended to elevate the firing vessel as far as an inch from the top of the chamber. It this spot the actual temperature in the kiln is the closest to what the controller displays.

Why not ramp slower than 1800°F per hour instead of holding at 1000°F (brick)/1100°F (muffle)? The binder needs a certain amount of time at 1000°F (brick)/1100°F (muffle). If you slow-ramp, you give it more time at temperatures lower than 1000°F (brick)/1100°F (muffle), a temperature not high enough for it to burn off, and very little time at 1000/1100°F, the temperature it actually needs.

I hope this shed some light on the process. Please feel free to ask for clarifications.

Four types of One-fire Flex Clay are now available on my Online Store: One-fire Flex Copper, Brilliant Bronze, Dark Champagne Bronze, and Low-shrinkage Steel XT. More types of One-fire Flex Clay will be available down the road.

Be sure to read the instruction manual, go over the projects, and watch the video “How Flexible is One-fire Flex Clay?“.

One great application of One-fire Flex Clay is carving and engraving. When handling thick pieces the clay is not flexible but very soft and lends itself tp both engraving and structural carving. Cuts like butter! The engraving was easy and fast. Here are two extruded pieces:

As promised in my last posting: “What Other Things Can Be Done with One-fire Flex Clay?“, I’ve prepared projects for some of the pieces featured in the posting.

The Instruction Manual for One-fire Clays now includes two pages dedicated to One-fire Flex (pp. 7-8). Please download this updated version.

Also, here is a little video showing how flexible the new One-fire Flex clay is:

This question has been asked quite frequently. Indeed, many things can be done with the One-fire Flex clay without using the Silhouette machine. I’ve been working with it quite a bit using punches, trimming scissors, embossing folders, and mostly – simple hand tools for etching, cutting and texturing. I re-made some pieces I’ve made in the past and discovered new, easier techniques for making them. Here is what I’ve done in the past week. Still working, more to come! Projects will be posted with the launch of the new clay!

While developing the new line of One-fire Flex Clays, we decided to simplify the user interface for both our online store and our blog. The clays are now organized in groups according to their type and firing schedules. The instruction manuals are now down to three short ones: one for One-fire Clays (including the new line of Flex clays), a second for Quick-fire Clays (including Traditional/Flex clays), and a third for cold inlay powders. Each product on the store includes a description with a direct link to its respective instruction manual.

While re-organizing the store we also changed some of the products’ names. This, too, is meant to simplify things. The changes are in the One-fire category only: all clays that use a one-phase firing schedule now start with the name “One-fire” instead of “Friendly.” For your convenience, we have also created a table that lists the products whose names have changed, showing the old names and the the new ones. Please refer to the document entitled “Map of Hadar’s Clay™ Products” to see the changes and the table. (This document is also available on the right-hand pane of this blog.)

Click here to find out.

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Meet One-fire Flex Low-shrinkage Steel XT:

Why do we need this one, since we already have Pearl Grey Steel?

Pearl Grey Steel shrinks much more than other clays. Here is how much it shrinks compared to copper:

This makes it hard to fire it with other clays, since the difference in shrinkage will cause the whole piece to warp. Hammering flat is not an option since Pearl Grey Steel is very hard.

Low-shrinkage Steel XT (both One-fire and One-fire Flex) shrinks very little, which makes it a good candidate for combining with other metals.

Below is the same piece with the bird blackened with patina (I sure got a lot of mileage out of this bird punch).

The piece came out a tiny bit warped. Since Low-shrinkage Steel XT is not as hard as Pearl Grey Steel, it hammered flat easily with a blow of a plastic hammer, no cracking.

This brings the number of the One-fire Flex Clays to a total of nine. They will be released in groups, one group at a time. The first group will include Dark Champagne, Brilliant Bronze, Copper, and Low-shrinkage Steel XT.