Best Slip Casting Supplies: Casting Slip, Deflocculants and Molds
Updated How we research
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.
The short version
We compared 7 picks. Our scores range from 7.2 to 8.1 out of 10.
- Best overall:AMACO No. 15-S 1 Gallon Casting Slip. Highest overall score in this guide at 8.1/10.
- Also great value:Darvan 811 Deflocculant for Slip Casting, 1 Pint. Value score of 8/10, overall 7.8/10.
- Solid build:RT Vanderbilt DARVAN 7-N Dispersing Agent. Build and materials score of 9/10, overall 7.5/10.
- Feature-rich:Double Cavity Plaster Mold for Espresso Cups. Features score of 8/10, overall 7.8/10.
Scores are our editorial assessment, not customer ratings. How we score
As an Amazon Associate we earn from qualifying purchases. This does not change our picks. Affiliate disclosure
AMACO No. 15-S 1 Gallon Casting Slip
AMACO No. 15-S 1 Gallon casting slip, a ready-to-pour liquid clay for slip casting in plaster molds.
SIO-2 Aneto White Porcelain Casting Slip, 3.5L
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.
- 1.AMACO No. 15-S 1 Gallon Casting Slip8.1/10See on AmazonCheck price
- 2.SIO-2 Aneto White Porcelain Casting Slip, 3.5L7.9/10See on AmazonCheck price
- 3.Darvan 811 Deflocculant for Slip Casting, 1 Pint7.8/10See on AmazonCheck price
- 4.Double Cavity Plaster Mold for Espresso Cups7.8/10See on AmazonCheck price
- 5.RT Vanderbilt DARVAN 7-N Dispersing Agent7.5/10See on AmazonCheck price
- 6.Solidland Sodium Silicate for Pottery, 8.5 fl oz7.2/10See on AmazonCheck price
- 7.REFSAN Rio Plaster Slip Casting Mug Mold, 7.4 oz7.2/10See on AmazonCheck price
| # | Product | Our score | Price | |
|---|---|---|---|---|
| 1 | AMACO No. 15-S 1 Gallon Casting Slip | 8.1/10 | See on Amazon | Check price |
| 2 | SIO-2 Aneto White Porcelain Casting Slip, 3.5L | 7.9/10 | See on Amazon | Check price |
| 3 | Darvan 811 Deflocculant for Slip Casting, 1 Pint | 7.8/10 | See on Amazon | Check price |
| 4 | Double Cavity Plaster Mold for Espresso Cups | 7.8/10 | See on Amazon | Check price |
| 5 | RT Vanderbilt DARVAN 7-N Dispersing Agent | 7.5/10 | See on Amazon | Check price |
| 6 | Solidland Sodium Silicate for Pottery, 8.5 fl oz | 7.2/10 | See on Amazon | Check price |
| 7 | REFSAN Rio Plaster Slip Casting Mug Mold, 7.4 oz | 7.2/10 | See on Amazon | Check price |
AMACO No. 15-S 1 Gallon casting slip, a ready-to-pour liquid clay for slip casting in plaster molds.
Fit for the job 9/10 · Features and specs 7/10 · Build and materials 8/10 · Value 8/10
- + 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
- - Plaster molds are needed and are not included
- - Slip settles over time and must be stirred well before pouring
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.
Fit for the job 9/10 · Features and specs 7/10 · Build and materials 8/10 · Value 7/10
- + 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
- - 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
Darvan 811 deflocculant in a 1 Pint bottle from Ceramic Supply USA, an additive for mixing fluid, low-water casting slip.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 8/10 · Value 8/10
- + 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
- - 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
A twin double cavity 3-Piece plaster mold for slip casting 2.6 oz espresso cups in ceramic or porcelain clay.
Fit for the job 8/10 · Features and specs 8/10 · Build and materials 7/10 · Value 8/10
- + 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
- - Espresso size is too small for everyday mugs or tea cups
- - Two cavities mean more drying time before the mold can be reused
RT Vanderbilt's DARVAN 7-N premium liquid dispersing agent, a deflocculant for stable ceramic casting slips and glazes.
Fit for the job 8/10 · Features and specs 6/10 · Build and materials 9/10 · Value 7/10
- + 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
- - Check the bottle size against how much slip you process
- - Industrial-style packaging offers little guidance for beginners
SOLIDLAND's 8.5 FL.OZ sodium silicate solution at 40% concentration, a water glass for slip casting and pottery uses.
Fit for the job 7/10 · Features and specs 7/10 · Build and materials 7/10 · Value 8/10
- + 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
- - Sodium silicate can gradually glaze and seal plaster mold surfaces
- - Small 8.5 FL.OZ bottle suits testing more than big slip batches
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.
Fit for the job 8/10 · Features and specs 7/10 · Build and materials 6/10 · Value 7/10
- + 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.
- - 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.
Before you buy: trade-offs we flagged
No pick is perfect. These are the main compromises we noted for the top products in this guide, so you can check they will not matter for you.
- Plaster molds are needed and are not included (AMACO No. 15-S 1 Gallon Casting Slip)
- 3.5 liters is a little under one US gallon, so larger molds or production runs need several containers (SIO-2 Aneto White Porcelain Casting Slip, 3.5L)
- Dosing takes testing, and too much can make slip thicken again (Darvan 811 Deflocculant for Slip Casting, 1 Pint)
- Espresso size is too small for everyday mugs or tea cups (Double Cavity Plaster Mold for Espresso Cups)
- Check the bottle size against how much slip you process (RT Vanderbilt DARVAN 7-N Dispersing Agent)
- Sodium silicate can gradually glaze and seal plaster mold surfaces (Solidland Sodium Silicate for Pottery, 8.5 fl oz)
Frequently asked questions
›What is the best choice among slip casting supplies: casting slip, deflocculants and molds?
AMACO No. 15-S 1 Gallon Casting Slip is our top overall pick. AMACO No. 15-S 1 Gallon casting slip, a ready-to-pour liquid clay for slip casting in plaster molds. It earns our score of 8.1/10, based on fit for the job, features, build and value.
›What is a good budget option?
SIO-2 Aneto White Porcelain Casting Slip, 3.5L is the strongest low-cost pick in this guide. 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.
›How much should I expect to spend?
Picks in this guide span See on Amazon price bands (roughly: $ = under $30, $$ = $30 to $100, $$$ = over $100). We never display exact prices because they change constantly, so the buttons above always show Amazon's current price.
›How were these products chosen?
We shortlist products that fit the job this guide solves and compare their published specifications, such as size, capacity, materials and what is included. Each pick gets an editorial score out of 10 for fit, features, build and value, and we write the pros and cons from those details. Our score is not an Amazon customer rating. We earn a commission if you buy through our links, which never affects the ranking.
Pottery Nest independently selects every product; we may earn a commission from links above.
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