# Best Slip Casting Supplies: Casting Slip, Deflocculants and Molds Source: https://potterynest.com/best/best-casting-slip Updated: 2026-10-30 Publisher: Pottery Nest. Our score is an editorial rating out of 10 (fit 35%, features 25%, build 20%, value 20%), not a customer rating. Method: https://potterynest.com/how-we-research#our-score Slip casting depends on three things working together: a slip that flows and drains cleanly, a deflocculant that keeps thick slip fluid without extra water, and plaster molds that draw moisture out evenly. When one is missing, casts crack, stick or come out with uneven walls. This guide covers all three. AMACO No. 15-S and SIO-2 Aneto porcelain (cone 6 to 8) are ready-to-pour slips. Darvan 811, Darvan 7-N and sodium silicate are liquid deflocculants for thinning slip. A 3-piece mug mold and a double cavity espresso cup mold finish the set. Check the firing range against your kiln first, then each product's stated use. ## Picks ### 1. AMACO No. 15-S 1 Gallon Casting Slip Our score: 8.1/10 (Fit for the job 9/10 · Features and specs 7/10 · Build and materials 8/10 · Value 8/10) AMACO No. 15-S 1 Gallon casting slip, a ready-to-pour liquid clay for slip casting in plaster molds. Pros: - Ready-to-pour slip saves mixing powder and deflocculant yourself - 1 Gallon container fills several small to medium molds - AMACO slip is widely used in schools and ceramic hobby shops Cons: - Plaster molds are needed and are not included - Slip settles over time and must be stirred well before pouring Details: https://potterynest.com/product/B0044S9G86 ### 2. SIO-2 Aneto White High Fire Porcelain Slip, 3.5L (Cone 6-8) Translucent Liquid Pottery Clay for Casting Our score: 7.9/10 (Fit for the job 9/10 · Features and specs 7/10 · Build and materials 8/10 · Value 7/10) SIO-2's Aneto White porcelain casting slip in a 3.5 liter container, firing at Cone 6-8 (1230 to 1270 C). A translucent white liquid porcelain ready to pour into plaster molds. Pros: - Ready-mixed porcelain slip described as smooth, stable and at the right consistency for casting in molds - Cone 6-8 firing range (1230 to 1270 C) suits the mid to high fire electric kilns common in home studios - Made in Spain by Ceramica Collet, in production since 1874, with ACMI AP non-toxic certification Cons: - 3.5 liters is a little under one US gallon, so larger molds or production runs need several containers - Listing gives no shrinkage, specific gravity or recommended casting time for the slip Details: https://potterynest.com/product/B0GT9X7491 ### 3. Darvan 811 Deflocculant - Ceramic Additive for Slip Casting & Pottery, 1 Pint, Ceramic Supply USA Our score: 7.8/10 (Fit for the job 8/10 · Features and specs 7/10 · Build and materials 8/10 · Value 8/10) Darvan 811 deflocculant in a 1 Pint bottle from Ceramic Supply USA, an additive for mixing fluid, low-water casting slip. Pros: - Darvan 811 thins slip with less water, reducing shrinkage and mold wear - 1 Pint bottle lasts a long time since only small doses are needed - Useful for potters who mix their own casting slip from clay or powder Cons: - Dosing takes testing, and too much can make slip thicken again - Not a slip itself, so you still need clay or dry materials to mix Details: https://potterynest.com/product/B0F2P65WWF ### 4. Twin Double Cavity Plaster Mold for Slip Casting Espresso Cups, 3-Piece Pottery Mold for Ceramic and Porcelain Clay, 2.6 oz Our score: 7.8/10 (Fit for the job 8/10 · Features and specs 8/10 · Build and materials 7/10 · Value 8/10) A twin double cavity 3-Piece plaster mold for slip casting 2.6 oz espresso cups in ceramic or porcelain clay. Pros: - Double cavity casts two espresso cups per pour to save time - 3-Piece mold captures a clean form for matching cup sets - Small 2.6 oz cups use little slip per cast Cons: - Espresso size is too small for everyday mugs or tea cups - Two cavities mean more drying time before the mold can be reused Details: https://potterynest.com/product/B0BJFLDLL7 ### 5. RT Vanderbilt DARVAN 7-N Premium Liquid Slip & Glaze Dispersing Agent - Deflocculant for Stable Ceramic Casting Slips & Glazes Our score: 7.5/10 (Fit for the job 8/10 · Features and specs 6/10 · Build and materials 9/10 · Value 7/10) RT Vanderbilt's DARVAN 7-N premium liquid dispersing agent, a deflocculant for stable ceramic casting slips and glazes. Pros: - Made by RT Vanderbilt, the original manufacturer of the Darvan line - 7-N formula helps slips stay stable over longer storage - Doubles as a glaze dispersant to reduce settling in buckets Cons: - Check the bottle size against how much slip you process - Industrial-style packaging offers little guidance for beginners Details: https://potterynest.com/product/B07X13KL43 ### 6. SOLIDLAND Sodium Silicate Solution for Pottery & Ceramics - 8.5 FL.OZ - Water Glass for Glazing, Slip Casting, Deflocculant - 40% Concentration Our score: 7.2/10 (Fit for the job 7/10 · Features and specs 7/10 · Build and materials 7/10 · Value 8/10) SOLIDLAND's 8.5 FL.OZ sodium silicate solution at 40% concentration, a water glass for slip casting and pottery uses. Pros: - Sodium silicate is a low-cost classic deflocculant for casting slip - 40% concentration is clearly stated, which helps with dosing - Also useful for crackle texture effects on thrown pieces Cons: - Sodium silicate can gradually glaze and seal plaster mold surfaces - Small 8.5 FL.OZ bottle suits testing more than big slip batches Details: https://potterynest.com/product/B0GVPD8SF8 ### 7. Rio Plaster Mold for Slip Casting Mug, 3-Piece Pottery Mold for Ceramic and Porcelain Clay, 7.4 oz Coffee Cup Our score: 7.2/10 (Fit for the job 8/10 · Features and specs 7/10 · Build and materials 6/10 · Value 7/10) REFSAN Rio three-piece plaster mold for slip casting a 7.4 oz coffee cup with a handle. From the same brand as the mold it replaces, for ceramic or porcelain slip. Pros: - Three-piece interlocking design holds the liquid clay and is described as pulling apart cleanly for demolding. - Makes a finished bisque coffee cup of 7.4 oz, 3.54 inches tall with a 2.75 inch rim, though some shrinkage is expected. - Listed lifespan is about 100 uses with gentle sponging and full air drying between pours. Cons: - Only for liquid clay slip: the listing says not to use it with concrete, resin, extra plaster or stone powder. - Makes one cup shape at one small size, so it suits a mug line rather than varied forms. Details: https://potterynest.com/product/B0CGRDTYLT As an Amazon Associate I earn from qualifying purchases.