Two weeks ago a new feature was added to the Hadar’s Clay™ Users Discussion Forum. I am adding this feature to the blog and will also post it on my Facebook page. The Users Discussion Forum is a wonderful tool for sharing information, discussing issues, and showing your work. As of today there are currently 935 members. You are welcome to join.
Here is the new feature: Every week, on Sunday, a multiple-choice question is posted. The posted questions may range from beginners’ level to accredited teachers level. Some of them may sound obvious; some may sound complicated. The suggested answers to each question may be incorrect, partially correct, or reasonably correct. However, there is only one correct answer, which is the best answer.
You don’t have to post your answer. These questions are meant for you to test yourself and clarify issues regarding the nature and use of Hadar’s Clay and other brands of base metal clay. I will post the answers halfway through the week, so you can compare your answer to mine. Then, if questions arise, you can post them on the Users Discussion Forum, on this blog, or on my Facebook page, or you can email them to me and I will post and answer them without disclosing your identity. You are welcome to discuss the questions and the answers. You are also welcome to email me questions that you would like to see discussed.
Here are the two questions and answers that have already been posted on the Support Forum. The third question will be posted this coming Sunday.
First question: Can you fire Hadar’s Clay with a torch?
3. Yes, but you need to do it for at least one hour.
4. Torch-firing Hadar’s clay is not recommended.
5. Only One-fire Copper can be fired with a torch.
6. You can fire base metal clay with a torch, but then you need to re-fire in carbon.
7. You can fire base metal clay with a torch only if you manage to cover the whole piece with the flame so it is not exposed to oxygen.
The best answer is #4.
Second question: True or false: Pieces cannot sinter under carbon because the binder has no oxygen to burn out.
2. Not true: there is always enough oxygen under the carbon for the binder to burn out.
3. It depends on how much carbon there is on top of the pieces.
4. It depends on the type of carbon.
5. Above a temperature of 1000°F (brick)/1100°F (muffle) there there may not be enough oxygen in the carbon for the binder to burn off.
6. It depends on the total amount of carbon per number of pieces.
7. It depends on how many times the carbon has been used.
The best answer is #5.
[UPDATE: By popular demand, in addition to the intensive described below, I have added another intensive on March 11-15, 2016. You can sign up for the March intensive directly on my Online Store.]
Since my January intensive is full, I have scheduled another one for January 2-6. This 5-day intensive takes place at my studio in Berkeley, California. In this workshop no commercial or pre-made textures and forms will be used; you will be making your own molds and textures for constructing unusual forms and decorating your creations. Different techniques for color and inlay will be included if time allows.
The full cost of the intensive is $500 plus materials. You can sign up here. Upon signing up I will email you the exact address, a list of tools to bring, and places to stay. You can ship your tools to my studio ahead of time.
This workshop is intermediate to advanced and recommended to people with experience with Hadar’s Clay.
Feel free to email me with specific questions at: firstname.lastname@example.org.
Here are a few photos representative of what we will be doing at this workshop. The samples include drawer knobs, salt and pepper shakers, push pins, mini pots, door knocker and switch plate covers but you can use these techniques to make jewelry objects.
Hand-made texture, color and inlay:
Hand-made texture and color:
Forms made with a new mold material:
Salt and pepper shakers:
Switch plate covers:
One-fire Flex Pearl Grey Steel is now available on our online store. This completes the release process of the One-fire Flex Clays, which include One-fire Flex Copper, Brilliant Bronze, Dark Champagne Bronze, Rose Bronze, White Bronze, Low-shrinkage Steel XT, White Satin, and Pearl Grey Steel.
Please download the Instruction Manual for One-fire Clays by clicking on the link in this sentence, or directly from the right-hand panel of my blog. The instructions for One-fire Flex clays are on pp. 7-8.
One-fire Flex Pearl Grey Steel works best in combination with other metals (One-fire Bronze or Brilliant Bronze and one-fire Copper) for color effects (caning, mokume-gane, and gradients). The photos below show One-fire Flex Pearl Grey Steel as part of a gradient surface, fired at mid-fire schedule.
The following photos show One-fire Flex Pearl Grey Steel fired in a stripe pattern with One-fire Copper and Brilliant Bronze at mid-fire schedule.
One-fire Flex Pearl Grey Steel can also be fired on its own at 1750°F but will be too hard to bend and drill. To fire steel on its own it is recommended to use Low-shrinkage Steel XT.
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.
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.
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.
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.
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!