Ceramic Mold Making Techniques

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ceramic mold making techniques

tips for making plaster molds and slip casting clay

Plaster molds make it possible for you to repeat complicated patterns and create forms not possible to efficiently construct using any other pottery technique. For thousands of years, potters used bisqued clay for molds but the major drawback was that they could not get a lot of detail. With the discovery of plaster in the 17th century, potters immediately saw the advantages and plaster has been the choice for ceramic molds ever since.

10 Steps to Perfect Plaster by Bill Jones

Before you can make a ceramic mold you need to know a little about plaster. Plaster can sometimes be a finicky material but if you follow these ten essential guidelines, you’ll be on your way to making successful plaster molds for slip casting. How to Make a Simple Plaster Press Mold by Gary Carlos

A press mold is the simplest mold to make and this step-by-step process by master tile maker Gary Carlos is easy to follow. He guides you through making a basic ceramic mold and making a plaster cavity mold. How to Make Plaster Molds for Double-Walled Vessels by Hiroe Hanazono

Double-walled vessels are difficult to make – especially when you want the fantastic forms Hiroe Hanazono creates. Hiroe always had a great passion for food and her voluminous serving pieces certainly reflect that. She demonstrates how to make the model and the plaster molds for a delicious ice cream bowl and topping server. How to Make Casting Slip from Your Clay Body by Paul Andrew Wandless

You can buy pre-made slip for slip casting in all firing ranges, which is a really practical thing to do in many situations. The disadvantage is that whatever you cast will not match you regular clay body. Paul Wandless shows you how to make casting slip from your regular clay to eliminate this problem.

hether you need a drying bat, a simple hump mold, or you’re making a complex slip mold, Water to Plaster Mixing Chart you’ll need to mix plaster. Getting the plaster 1 quart. . . . 2 lbs . 14 oz . (1,293 grams) right requires a bit more than just “dumping 1¹/2 quarts. . . 4 lbs . 4 oz . (1,937 grams) Wand mixing.” Here are 10 ways to get the best results for your 2 quarts. . . . 5 lbs . 11 oz . (2,585 grams) next plaster project. 2¹/2 quarts. . . 7 lbs . 2 oz . (3,230 grams) Prepare your mold. A common mistake potters make is to 3 quarts. . . . 8 lbs . 9 oz . (3,878 grams) mix plaster only to realize everything’s not set up for pour- 3¹/2 quarts...... 10 lbs . (4,522 grams) 1 1 gallon. . . . 11 lbs . 6 oz . (5,171 grams) ing. Before casting, make sure your model is set, the mold boards 1¹/2 gallons. . 17 lbs . 2 oz . (7,756 grams) or cottles are secure, and all the surfaces you’re pouring onto are 2 gallons . . 22 lbs . 13 oz . (10,337 grams) coated with a parting agent such as mold soap. 2¹/2 gallons. 28 lbs . 8 oz . (12,923 grams) Prepare your work area. You will need a clean mixing con- 3 gallons . . . 34 lbs . 3 oz . (15,508 grams) 2tainer for the plaster, a scale for weighing the plaster, a mea- This table is based on USG® No . 1 Pottery Plaster mixed to a consistency suring cup for the water and a rinse bucket. Note: Plaster cannot of 73 (73 parts plaster to 100 parts water) recommended for most studio be permitted to go down the drain, because it will form a rock- applications . Excessive water yields a more porous but more brittle mold, and less water means a very dense, hard mold that will not absorb water . like mass. Even small amounts will accumulate over time. Line a rinse bucket with a plastic garbage bag and fill it with water for rinsing your hands and tools. Allow the plaster to settle for a day, soaking time is too short, it may contribute to pinholes; and if it then pour off the water and discard the bag. is too long, it will contribute to fast set times, early stiffening and Use fresh water. The mixing water you use should be at room gritty mold surfaces. temperature or 70°F (21°C). If the water is too warm, the 3 Mix the plaster. Small batches of plaster can be mixed by plaster will set too fast and vice versa. Use only clean, drinkable hand. Use a constant motion with your hand and you will tap water or distilled water. Metallic salts, such as aluminum sul- 8 notice a change in consistency from watery to a thick cream. fate, can accelerate the setting time, and soluble salts can cause Break down lumps with your fingers as you mix. Mix only for efflorescence on the mold surface. a minute or two being very careful not to agitate the mixture Use fresh plaster. Plaster is calcined, meaning chemically so much that air bubbles are incorporated into the mix. Mix- 4bound water has been driven off through heating. If the plas- ing time affects absorption rates—longer mixing times produce ter has been sitting around in a damp environment, it will have tighter and less-absorptive molds. lumps in it, in which case it is no longer usable. Pitch it. Use Pouring the plaster. After mixing, tap the bucket on a hard plaster that has been stored dry and is lump free. 9surface to release trapped air. Pour the plaster carefully. Weigh out materials. Do not guess about the amounts of plas- Wherever possible, pour plaster carefully into the deepest area so 5ter and water you’ll need. Once you start the mixing process, the slurry flows evenly across the surface of the mold. Once the you do not want to go back and adjust quantities. To determine mold is poured, tap the table with a rubber mallet to vibrate the the amount you need, estimate the volume in cubic inches then mold and release more air bubbles. divide by 231 to give gallons or by 58 to give quarts. Deduct Drying plaster. When plaster sets, it heats up because of 20% to allow for the volume of plaster, then refer to the table. 10 a chemical reaction. When it has cooled, it is safe to re- Add plaster to water. Slowly sift the plaster onto the surface move the cottles or forms—about 45 minutes to an hour after 6of the water. Do not dump the plaster or toss it in by hand- pouring. Molds must be dry before use. Drying molds properly fuls. Adding the plaster shouldn’t take more than 3 minutes. promotes good strength development, uniform absorption and Soak the plaster. Allow the plaster to soak for 1–2 minutes reduced efflorescence. Dry molds evenly. Don’t set them near a 7maximum. The soaking allows each plaster crystal to be kiln where one side is exposed to excessive heat or the relative completely surrounded by water and it removes air from the humidity is near zero. Place them on racks in a relatively dry mix. Small batches require less soaking than large batches. If the location away from drafts. n

Blue Streets, 2001, 23×23 inches, made from earthenware and using low-fire glazes.

fter college, and while working part-time for Blue Streets detail. a small slip-casting stu- A geometric pattern dio, I began to explore was first carved into a A plaster block. I pressed a career in art education. This ex- a tile with this pattern ploration led me to San Francisco’s and added the small vibrant mural community. Crafting house-like elements. a work that will hold up in the face A cavity mold was of extreme weather conditions and then made from the graffiti is of great concern to mural finished tile. painters. Many muralists have re- discovered that ceramic tile has always been an attractive, alternative Freeway, 2001, 11×17 medium to paint. inches, made from earthenware and With a background in both paint- using underglaze, ing and ceramics, in addition to stains, and glaze. For my interest in public art, working this piece the original in tile seemed like a natural pro- tile prototype was gression for me. I find it extremely made completely out satisfying to bring work out of of clay. the studio and into public spaces, where it can become a living part of the community. As my interest in tile grew, a col- Hive, 2000, individual league told me about the historic tiles are 4 inches wide, Moravian Pottery and Tile Works made from earthenware with oxides, glaze, and in Pennsylvania. Within weeks I grout. This hexagon- was on a plane to attend one of shaped tile has a shallow their 3-day workshops. In that short Y-shaped groove cut into time I learned many of the simple it for grout, making it techniques tile makers have used for appear as three separate centuries. In the years since, I have shapes, adding another element to the design.

found my own way of using tile to coated with sealer. Remember to explore a variety of themes in my always use a release agent, such as work. I hope this brief introduction oil soap, on a porous surface before to tile making allows you to dis- pouring plaster on it. cover some new possibilities in your Cut additional square pieces of own work as well. laminated board as templates for plaster molds. When determining Making a the size of your template, accommo- Basic Mold date for clay shrinkage in the final Start by making a good set of tile: if you’re using a clay body that adjustable mold boards (figure 1). shrinks 12% you’ll need a 4½-inch Cut four laminated boards (¾×5×12 mold for a 4-inch tile and a 6¾-inch inches is a good size). Attach a 90° mold for a 6-inch tile. Assemble framing bracket (available at hard- the mold boards snugly around the ware stores) flush to one edge of template (figure 2). The mold should each board. Caution: If you are not be level so check your work surface comfortable using power tools have with a level and adjust it with shims someone who is do this step for you. if necessary. Most home centers will cut wood to Fasten the boards together with your specifications. four spring clamps (figure 3) or Good plywood also works for C-clamps. If the boards are all mold boards, but use mold soap cut accurately at right angles, the on them. Try to get wood covered assembled form will keep plaster in Formica. Shelving sold in most from leaking without the need to home centers is only covered with seal the joints with clay. Since lami- thin contact paper. This will work, nated wood is nonporous, it also but after continuous use it will begin eliminates the need for a release to deteriorate around the edges. Try agent. Put a wad of clay at the a local cabinet shop for scraps or a base of each wall to keep the form home center for a damaged counter- secure (figure 6). top. If you can’t get laminated wood For most studio applications, I use for templates or a smooth work sur- #1 Pottery Plaster. Make sure the face to pour directly on, try Plexi- plaster is fresh (stored for no more glas, glass, or fine-grained plywood than 6 months) and completely free

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of moisture. Measure room-temper- 6). Shake the table (but not too ature water and plaster by weight much) to bring any air bubbles to (figure 4) in a ratio of 0.7 parts the surface, and to settle the plaster water to 1 part plaster. Use 1 lb out, making the top completely flat. water to 1.4 lb plaster for a 4½-inch Swirl some water in the dirty mixing square mold and 2.1 lb water to 3 lb container immediately and dump it plaster for a 6¾-inch square mold. into a waste bucket. Note: I’ve used decimals not ounces. Caution: Never pour plaster or Slowly sift the plaster into the plaster waste water down a drain. water (figure 5). Once all the plaster When plaster sets, it gives off is in, allow it to soak (slake) for one heat. After about 30 minutes it will minute without any agitation. Mix cool back down and you can then the plaster with a clean stick until it take the form apart (figure 7). If the becomes a heavy cream consistency boards stick give them a quick tap (a milkshake consistency is too away from the mold and they will thick). This should ideally take 2 to pop off. Tip: Pouring a few of these 3 minutes, but can happen any- plaster blanks is a good way to get where from 1 to 5 minutes. used to plaster before trying some- When the plaster has reached a thing more critical. proper consistency, pour it into the Clean up the edges on the top of form in a slow steady stream (figure the mold with a scraper (figure 8).

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Leave the other side (facing the grooves to about ¹/16 -inch (fig- template) untouched; it should ure 11). This is most easily done already be perfectly flat and free when the plaster is damp. If the of air bubbles. This is the side you plaster block is dry soak it in will carve. some water for a few seconds. Create a scale drawing of your im- You can press some clay onto age (figure 9). Remember that your the mold to check what it will look final product will be a mirror image like, but allow the mold to cure of this, so if you use any text it will and reach full strength (about two need to be written backwards. To weeks) before using it for produc- transfer the design, place your draw- tion. Cut a slab of clay slightly ing over the block and trace it with larger than the mold (figure 12). a slight amount of pressure (figure Roll the slab out so that it is a bit 10). This will leave a shallow mark thicker than the desired tile thick- in the plaster. ness (figure 13). Use a straight edge If you have trouble seeing the to smooth the surface of the slab. design, scribble some graphite or Place the mold on top of the clay charcoal onto a piece of paper and place a wooden block on top and smear it on the block. Use a of the mold. Hit the wooden block hook tool or a V-shaped linoleum a few times with a rubber mallet block carving tool to deepen the until the clay squeezes out on all

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four sides (figure 14). If your table is absorbent board and allow the tile to not sturdy, you may want to do this dry evenly. on the floor. Caution: It is possible to crack a mold in half (more common Making a Cavity Mold with cavity molds). To avoid this, use If you have a sculptural tile and want soft clay and make sure the wooden to minimize distortion around the edg- block and plaster mold are both flat es, or want a consistent tile thickness, and free of debris. you should make a cavity mold. Make Trim the excess clay with a knife an original tile out of clay, avoiding un- before removing the mold (figure dercuts. Rub some water on the bottom 15). To keep the corners square, of the tile to create a thin slip and stick place your thumb at the end of each it to a board allowing a 1½-inch border cut. If the tile does not come off around all sides (figure 17). right away, set it aside and allow Pour the plaster at least 1½ inches the plaster to do its work. Before over the top of the tile—any less and long, the clay will stiffen up and the mold may crack during pressing. release easily (figure 16). One of the To use the mold, cut a slab of clay the things tile makers struggle with is same size as the opening (figure 18). preventing tiles from warping. Try Cover the clay with canvas and use a not to bend a wet tile as plastic clay rubber mallet and a block of wood to retains a memory. Place it on an press the clay into the mold.

Works. Use a wooden straight edge to scrape off and level the back of the tile (figure 21). You may want to sign or stamp the back at this point. Give the clay some time to set. This may vary greatly depending on the weather and dampness of the mold (figure 22). A finished fired tile If you want to make several and the original mold. production molds of the same tile, create a durable master with mold making rubber (figure 23). To do this, seal a cavity mold with oil soap (Murphy’s). When the soap If you get serious about tile, has dried, mix the 2-part mold you may want to invest in a making rubber and fill the mold tile press (figure 19). There are to the brim. When the rubber has several types available. I prefer cured, glue it to a board and use this converted arbor press. It is it as you would a clay master. Re- compact and applies over 2 tons member, if you are pouring plaster of pressure. Cracking molds is on plaster, always seal the plaster sometimes unavoidable, but, if it original with oil soap. is a problem, switch to a plaster After setting, if the tile still sticks mix of 2 parts #1 Pottery Plaster in the mold, gently tap the mold and 1 part Ultracal. on all four sides and the open-face Use a wire cutter to slice off the side with your palm or a rubber excess clay (figure 20). This home- mallet. Or try shooting air be- made wire tool is based on one tween the clay and plaster with an used at Moravian Pottery and Tile air compressor. n

Double-walled vessels cast from original molds, sprayed glazes, fired to cone 6.

’ve always had a great passion given space. Architects and interior for food—cooking, eating, set- designers must consider how people ting the table, and sharing in and furniture fit into the overall Ithe full dining experience. It’s design of a space. They consider why I make functional pots. The purpose, and how the space will be pots I create consist of simple line used. Potters must consider these forms with muted glaze colors, and same issues—good pots consider the work’s minimal aesthetic doesn’t purpose, use and that which they compete with anyone’s domestic will eventually contain. surroundings, nor with the food it The minimal design of my forms eventually holds. create an ideal setting for the display I’m especially fascinated with of food. Simple forms allow for design that’s clean and almost severe beautiful relationships between the in its simplicity, and attracted to forms themselves and the elements modern interior design and architec- contained within them. ture because both practices work to My surfaces are also simple foils frame and contain the contents of a for the display of food. The repeti-

www.ceramicartsdaily.org | Copyright © 2010, Ceramic Publications Company | Ceramic Mold Making Techniques | 9 1 2 3 Finished wooden patterns sealed Molduct tubing attached to a wire Pouring slip into the pour holes with polyurethane and coated with frame that will be embedded into using funnels. mold release. the top section of the mold.

4 5 6 Draining excess slip. Squeezing slip into pour holes using Flip the mold to allow slip to fill an ear syringe to fill the pour holes. pour holes and finalize the casting.

tion of simple geometric shapes and carving out a pattern, generally lines goes beyond the idea of deco- made from MDF (medium density ration, becoming an element that fiberboard), from which I then blends into the form. The patterns create a plaster mold. Once I have that I create could serve as the de- settled upon a design, a meticulous sign of the forms of my pots. They scale drawing is made from which could also be rendered subtly in I then begin laying out the MDF low relief on the surface of my pots, pattern. Because there is roughly without interfering with the simplic- 20% shrinkage in the casting body, ity of the presentation I desire. I make the pattern larger than the final piece I’m aiming to produce Making the Pattern (see box). Many other artists create I use slip casting in the produc- their patterns out of plaster or clay, tion of my forms. It’s the technique but I’ve found that wood and MDF that best satisfies my intent to create better suit my needs. I can control immaculately executed and unusual these materials better, with the forms. Each new piece begins by edges of my forms sharper and the

www.ceramicartsdaily.org | Copyright © 2010, Ceramic Publications Company | Ceramic Mold Making Techniques | 10 7 8 9 Use compressed air to release the Remove the mold when the piece Tracing a pattern on the surface casting. is leather hard. using prism projector.

10 11 12 Carving the traced lines with a Filling the incised lines with a Scraping excess slip flush to the needle tool colored slip surface.

transitions fairer. Also, the durabil- identify the location of the plug ity and longevity of the original holes. My molds are typically made pattern is a definite bonus. in four pieces—the bottom, two The patterns are fabricated using sides and the top. Sometimes I primarily woodworking tools— embed molduct tubing that’s been band saw, table saw, sanders, attached to a metal frame into one router, and various hand tools of the plaster sections to facilitate including scrapers, rasps, files, and removal of the wet slip cast form chisels. A great deal of time is also from the mold (figure 2). The spent sanding and refining the pat- tubing creates a porous channel tern. The final step in preparing the so that compressed air can circu- pattern for mold making is to seal it late through the mold and help to with at least three layers of polyure- release the section from the cast- thane (figure 1). ing with minimal distortion. With double-walled forms, you need to Making the Mold make special considerations when First determine the number of it comes time to make the molds. sections the mold will have and Simple open molds are not possible

www.ceramicartsdaily.org | Copyright © 2010, Ceramic Publications Company | Ceramic Mold Making Techniques | 11 for I have to enclose the pattern en- prevents the piece from exploding in impacts their survival through tirely in plaster to achieve a double the kiln as the air contained within all stages of my entire making wall. This also necessitates creating the double walled form expands process, from casting through plug holes for pouring the slip into during the firing process. firing. This is particularly true the mold and then for draining it. To create a subtle decorative ele- for my double-walled plates. ment for the surface of this piece, I Should the interior walls of one of Casting the Piece decided to use mishima, a slip inlay these castings touch, the chances Pour casting slip into the mold technique. Using Adobe Illustrator, that piece will survive decreases and allow to set until you achieve I create geometric patterns which substantially. My failure rate the desired thickness (figure 3). I then project onto the cast form, goes up, with losses happening in Drain the slip from the mold and al- tracing them in pencil and finally the casting process itself and in low the piece to set up for awhile. carving out the lines with a needle both the bisque and glaze firings. After draining the slip (figure 4), tool (figures 9 and 10). Colored slip Therefore, I have to remain aware you’ll want to fill in the openings in is then pushed into the incised lines from the very beginning—in the your form left by the drain holes, using a brush (figure 11). Once the sketching and drafting phase— otherwise the finished piece will slip is dry, the surface is scraped how thick the walls will be and have holes in the bottom. Squeeze a flush with a metal rib (figure 12) re- how that affects the form. small amount of slip into the pour moving all excess slip from the form. Then, during the casting holes using an ear syringe (figure 5). What remains, is a clear and clean phase I must be diligent with Plug the holes to keep slip contained pattern with the colored slip remain- my casting times to ensure the within mold then flip the mold over ing in the incised lines. wall thickness is consistent and to allow slip to fill the pour holes accurate, always trying to pre- and finalize the casting (figure 6). Firing serve the integrity of the negative When it’s time to de-mold the After bisque firing to cone 06 space within the pot and prevent- piece, blow pressurized air into I spray all of my glazes and fire ing the walls from fusing. the molduct tubing and through them to a very hot cone 6. All of Being a designer, mold-maker, the plaster, forcing a separation the double-walled pieces are down- and manufacturer brings me from the slip cast form and the fired as well, a process by which great joy. I enjoy the challenge mold (figure 7). cooling is slowed through the of creating unusual, well-defined gradual lowering of the tempera- forms for use. The wooden Cleaning Up ture within the kiln. It allows for patterns that I create for mold and Decorating a more even cooling of the inside making and the slip casting Allow the slip cast form to and outside of the form, which process enable me to successfully become firm enough to work on produces less stress on the overall achieve my intent. I have never (leather hard) then remove it from form. Larger forms are glazed both had formal training in slip cast- the mold (figure 8). Use metal scrap- inside and outside to maintain a ing or in mold making. Working ers and sponges to clean the edges balance of surface tension. The use in diverse artist communities I’ve and any other irregularities that of both of these techniques has re- been exposed to a great variety appear on the surface of the form. duced the amount of loss I experi- of artists who have shared their Using a small drill bit, poke two ence in the creation of these double tricks and techniques. holes in the bottom of the form to walled forms. It’s through this sharing and allow air movement between the I’ve found that the shape and this collaboration of sorts that I inside and outside of the piece. This size of the forms I design greatly am able to do what I do. n

common studio challenge is trying to keep the Preparing the Slip number of different clay bodies you have on The process of slaking clay to make it into slip is a hand to a minimum. Throwing, handbuild- simple one. Step one is to have a 5-gallon bucket filled ing, casting, and surface design techniques A 60–75% with your bone-dry clay then add water until often require different clay bodies to suit the demands it’s a few inches below the rim (figure 1). Let it slake for of how your work is created. Sometimes the clay bodies 24 hours then mix it by hand a little with a stick (figure also need to be in different forms such as regular moist 2). Once you’ve mixed the slip for about 5 minutes, use clay, slip or casting slip. If I’m handbuilding with a a drill with a paint mixer attachment to mix it into a cone 6 clay body and want to add a slip-cast element to smooth slurry, which should be the consistency of thick it, I’d be hard pressed to find a commercial cone 6 cast- cream. Use the stirring stick to check the consistency ing slip with the exact same shrinkage and absorption and find any lumps of clay that didn’t slake down (fig- characteristics. A singular work made of multiple clay ure 3). Keep mixing until the lumps are gone. bodies can cause several problems. Disparate shrinkage rates, maturation points, iron content, etc., can all have a negative effect on the final outcome of the work when Measuring Specific Gravity using different bodies. When possible, it’s always best At this point, I normally fill a quart container with to stick with the same body. the slip to use as a joining or brushing slip. The rest I My sculptural work combines moist clay for general use for casting slip. You’ll need to measure the specific construction and casting slip for volumetric elements gravity of the slip to determine if the water to clay or for use with various image transfer techniques to ratio is correct before deflocculating it with liquid address the surface. My solution is to use the clay sodium silicate or Darvan. To determine specific grav- body I’m working with and turn it into the differ- ity, which is a comparison of the weight of 100 ml ent types of casting slips I need. This assures that all of water (which is 100 g and therefore has a specific the parts and surface treatments shrink the same, fire gravity of 1) with the weight of 100 ml of whatever to the same cone, and all the glazes work the same liquid or slip you are working with. First tare (zero on all the different parts. The great thing about this out) the weight of a graduated measuring container approach is its simplicity. All you need is a 5-gal- on a scale then fill it with 100 ml of slip and see how lon bucket, a drill with a paint mixer attachment, a much it weighs in grams. Once you know the weight, deflocculant, and the clay body you want to use as a you divide it by the weight of an equivalent volume of casting slip. water (100g). This works out, in essence, to moving

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www.ceramicartsdaily.org | Copyright © 2010, Ceramic Publications Company | Ceramic Mold Making Techniques | 13 the decimal point in your weight measurement to the left by two places to get the specific gravity. Example: 183 g = 1.83 specific gravity. In general, a specific gravity of 1.80 to 1.85 provides good balance of fluidity and strength for most casting purposes. This number can vary, though, depending on exactly what is being cast. I’ve used it as low as 1.74 for volumetric casting and as high as 1.90 for casting flat slabs. Different clay bodies have different optimal specific gravities that are determined by good old-fashioned trial and error. Spe- cific gravity is simply a tool for you to adjust your slip to meet the needs of your particular casting project. Once you find a number that works, write it down and stick with it for that clay body. If you have a specific gravity that is higher than 1.85 and you want to bring it down, add a little water (only a few drops at a time), to your slip, mix and re-test. If the specific gravity is lower than 1.80, let the slip sit 24 hours, skim the water off the top, remix, and measure the specific gravity again. also had the exact same success slaking down Deflocculating clay that started off as moist clay fresh out of the bag or as 3-day old bone dry clay. I keep a the Slip 5-gallon bucket around to throw all my scrap Once you have the correct specific gravity, clay into and when it gets about 65–75% full, you need to add a deflocculant to the slip to I turn it into casting slip. I also just slice up a make it more fluid so it can be poured. Typi- 25-pound bag of commercial clay into 1-inch cally just a few small drops of liquid sodium cubes and fill an empty bucket with them and silicate or Darvan is needed to achieve the use that to make my casting slip. I’m aware of appropriate fluidity. Clay bodies with high the different opinions regarding initial water iron content will require less deflocculant than content of the clay and its effect on the speed others. Use the drill to mix the deflocculant of water absorption/saturation while slaking. into the slip and use a ladle or pitcher to scoop In my personal experience, I’ve found if you let some of the slip out to see how it pours. The clay in any state of moisture slake for 24 hours, consistency of cream is what you’re going for it all mixes up just fine. I suggest you simply so be careful not to over-deflocculate the slip, slake your clay in the state of moisture that you which will cause slow uneven drying and soft typically have in the past. n spots in the finished piece. Just add a few drops at a time to achieve fluidity and remember a Paul Andrew Wandless is a studio artist, workshop little goes a long way with deflocculants. presenter, educator, and Vice President of the Pot- ters Council. He authored the book Image Transfer On Clay and co-authored Alternative Kilns and Firing Using What Works Techniques: Raku, Saggar, Pit & Barrel. His website is I’ve done this process with commercially www.studio3artcompany.com and he can be emailed at bought clay and with home made clay. I’ve [email protected].