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If you are reading this before you purchase a stamp and thinking about what kind of design to submit for a custom stamp, remember that some designs are easier to use than others. If you have a lot of little text letters or other details, your stamp will require more skill and experience to use. You may want to consider a more bold simple design that will be easier to use, especially for your first stamp. We can cut very complex stamps, but that does not mean they are easy to use. Like most clay methods, skill and experience affect the results. Experienced potters do amazing work with very complex stamps, but I would not recommend everyone start there. The old saying "less is more" definitely applies to stamp designs for easy fun results.
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You might wish to watch this video demo from Bear Hands Art Factory, showing stamping technique on the bottom of various size and shape pieces. Note that she is using one of our clay stamps along with corn starch for release agent. The fixture is a Stamp-Eaze If you are stamping the side of a vessel with a logo that would be a different process. Usually stamped flat medallions of clay on a table for support are then attached to the vessel using score and slip technique. |
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Stamping clay is like all other techniques in art, it takes practice to get the feel for when to stamp, how hard to press, when other tools are needed in addition to the stamp itself. Practice on some scrap pieces before you go to mark your best work. Everyone wants to go right into the studio and try out the new stamp on a piece of clay, but there is nothing more frustrating than making a poor mark on an excellent piece of work you already put a lot of time into. And let the clay get to the correct firmness for best results, there is a time element in use of stamps with water based clays. Like most skills with clay art work, practice is the best way to achieve cool results. If you are not getting the results you want after some trial and error then some of the following techniques might help. The variables in what works with clay stamping are the clay itself, the location of the mark on the piece, and the size and surface area of the stamp tool you are using.
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If you are working with water based clay, let it dry a little before you stamp. In my studio this often means overnight (under loose cover), but your studio may be different. Our wood surface and Signature Writer (R) Surface has about 1/8" depth and if you are careful not to press extra deep you should be able to get a nice mark without picking up the background of the stamp base. If you do pickup a mark from the edge of the tool, just smooth it away with your finger. If you are stamping directly onto the work as shown here you might need to roll the stamp from left to right around the curve of the pot to get the best results. This works well for small stamps. If the size of the stamp is too large to press directly onto the work, you might need to use a medallion of clay that is stamped first and then attached.
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Many potter's want to stamp the bottom center of thier wheel thrown work. This can also be one of the hardest places to get a complex mark to work. The piece is usually a little concave on the bottom, and even if flat, once you start to press in the stamp tool the bottom will move down and more in the center than the edges. This can lead to a problem where the center of the mark is not as deep as the outside. It is a common problem, and something the stamp itself can only go a small way to avoid. If requested we can sometimes make the center elements of a design slightly higher in the middle of the stamp than the outside edge. But the more effective 3 solitons are as follows:
1. support the clay from inside as you stamp it.
2. keep your mark small & simple (3/4" / 17mm or less)
3. mark in a different location.
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Once your stamp size reaches about 2", you probably want to use the medallion technique. That means first stamp a flat medallion of clay, then attach attaching the medallion of clay to your piece with slip and score method. This has one added advantage when you glaze the piece in that you can wipe this raised area clear of glaze to define the space for the mark. You can of course mark directly on the work OR you can mark slab pieces before you hand build them. But for most production of mugs for example, the medallion technique prevents distortion problems when attempting to press a large image directly onto a piece Some stamps get so large you might want to use a press to get the best mark, as your whole body weight might not be enough to press a 3" or 4" size stamp into the clay without too much effort. |
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Release Agents:
Our stamps surfaces will release from clay well if all conditions are right, but what if they are not? To avoid problems it is always beneficial to use some kind of release agent on either the stamp itself or the clay surface. There are many to choose from and partly this depends which type of tool surface you are using and what type of clay. For wood surface stamps, if you apply a very thin coating of vegetable oil on the stamp surface this will help achieve a good stamp mark even if the clay is a little too wet. I apply using a small 5mm size paint brush, and be sure to coat down into the small areas of the design. The vegetable oil works well on both wood stamps and our premium Signature Writer (R) Stamps. If you are having trouble with clay sticking in the detail areas of your stamp try using a release agent, it almost always solves the problem. You might have to re-coat the stamp after every so many marks. |
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Our customer's have told us the best release agent to use on your stamps might be WD-40. This works especially well on larger logo stamps for mugs, etc. Spray on the stamp surface before you mark the clay. Re-coat the surface as needed. A spray oil like this is highly recommended if you are using a press to stamp the clay. The oil helps the stamp release from the clay even when several hundred pounds of pressure are applied.
1. helps small details release from the stamp
2. lets you stamp clay that is too wet
3. also helps clay that is too dry
4. required when using a press
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I have been using corn starch on larger slabs of clay recently, using a paint brush to "powder" the stamp or roller and then I blow off the excess powder before I mark the clay. Or another nice trick is to make a small powder bag from 2 white cotton socks, one inside the other. You just need the toe parts, put some corn starch inside the double layer socks and tie them shut. The powder bag created will apply a nice even coating of corn starch on larger surfaces or the sides of pots to be stamp marked or rolled with texture. Takes a little practice to get the right amount of powder but works well. In this example I am using our 4" textured clay roller to make a field of design on the slab of clay before I cut it to shape. You can see all our texture rollers if you click here.
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Other release agents people use are talc powder, WD-40, corn starch powder, fine kaolin clay, and vegetable oil to aid in separation of the stamp from the ceramic clays. For polymer clay or precious metal clay (PMC) there are special release agents used for the those clays and they work best with our Signature Writer (R) Surface stamps. Wood stamps are not recommended for PMC. For very large stamps (4-5") many people use a hand press because more pressure is needed to make a good mark in clay. |
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Using a press:
Hand presses are nice, if you have access to one. The one shown here is a Palmgren 1 ton arbor press. As stamps get bigger, say more than 3" size a press like this or some other way to leverage your weight becomes needed to press the stamp evenly and deeply into the clay. We have some big guys in the shop and even with their full weight you just can not push as deep or even as a press can achieve with larger stamps and much less effort. We still use the knob or handle as shown here and it acts like a pivot to keep the stamp level while it presses into the clay. We build up a flat table to support our clay piece out of wood as shown in the photo. A smaller 1/2 ton press will probably work also for a little less cost. WD-40 spray oil is recommended for release.
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Using a support inside:
As discussed above, stamping center bottom on your work might be one of the most common desired locations and hardest to do. The larger the stamp, and the more surface area, the more you will need some kind of support fixture inside the pot while you make your mark. Shown here is the Stamp-Ease fixture, which we distribute for Bear Hands Art Factory. But you can make your own support using a simple dowel and attaching a sponge or disk of wood to the end. You just need something to support the clay in that middle bottom area, where the clay is weakest, during that 3 seconds while you press the stamp into the clay. Without the support some stamps just will not work. With support, a very complex stamp will work. If you wish to mark your work in this location, take a little time to find, buy, or make a support fixture and you will have a much more satisfying experience.
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Summary information:
- Best release agent for custom stamps - WD-40
- Good release agent for wood stamps - Vegetable Oil
- Corn starch on slabs of clay for wood rollers
- Support clay using Stamp-Ease or other fixture
- Arbor Press - we use 1 ton Palmgren for large stamps
- Less is more - simple designs are easier to use in clay
- Clean your stamp with tooth brush and cold water
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Video demo from Bear Hands Art Factory, showing stamping technique on the bottom of his pottery using a support fixture. The fixture is called Stamp-Eaze but you could also make something like this in your studio. This video demonstrates how best to stamp center bottom on pottery. The smaller your stamp, the less you will need support like this.
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Supporting the inside of a wheel thrown piece is key to success with marking the center area. Support inside when you stamp ensures all of the mark imprints to the same depth and you get clean crisp marks without distortion. The bigger the stamp, the more you need this support inside for good results.
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To care for your stamp
- Do treat with vegitable oil to prevent clay sticking
- Do clean with a little cold water and soft tooth brush
- Do press strait in or with slight rocking motion for best results
- After clay is dry it is OK to use a needle tool to pick out clay
- Do keep the stamp out of the slop bucket or sink
- Do NOT let the stamp soak in hot water
- Do NOT put in a dish washer
- Do NOT use solvents to clean
- Do NOT drop on concrete floors
- Do NOT let your dog near it, they will have new chew toy!
If clay does stick, clean it out with cold water and a soft toothbrush. A needle tool can be used, but be careful not to apply too much pressure.
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