Slip To Mix
3.30 qt
Dry Clay Yield
22.6 oz
Cycle
34 min
Slip Batch Needed
3.30
quarts
Retained Slip
31.4 oz
Dry Clay Yield
22.6 oz
Reclaim Slip
74.2 oz
Retention Ratio
33%
Cycle time: ~34 min per round (including fill, drain, cleanup).
Inputs
Result
Fill = 24 × 4 × 1.1 = 105.6 oz (3.30 qt). Retention = 0.3 + (14−8) × 0.0045 = 32.7%. Retained = 96 × 0.327 = 31.4 oz. Dry = 31.4 × 0.72 = 22.6 oz.
Inputs
Result
Fill = 12 × 8 × 1.1 = 105.6 oz (3.30 qt). Solid casting retains 100%: 12 × 8 = 96 oz. Dry = 96 × 0.75 = 72 oz. Cycle = 20 + 35 = 55 min.
Mix enough slip to fill every mold completely plus 10% overfill for handling loss. For 4 molds at 24 oz each, you need about 3.3 quarts of slip. Hollow casting reclaims most of the excess; solid casting retains it all.
| Casting Type | Retention | Reclaim |
|---|---|---|
| Hollow (thin) | 22–27% | 73–78% |
| Hollow (standard) | 28–35% | 65–72% |
| Hollow (thick) | 36–45% | 55–64% |
| Solid | 100% | 0% |
Longer drain times build thicker walls. Each extra minute adds about 0.45% retention because more clay solids collect against the plaster mold surface before the excess is poured out.
Dry yield is the retained slip multiplied by the solids factor of your clay body. Stoneware slip has about 72% solids, earthenware about 68%, and porcelain about 75%.
| Clay Body | Solids Factor | Dry Yield (from 30 oz retained) |
|---|---|---|
| Earthenware | 68% | 20.4 oz |
| Stoneware | 72% | 21.6 oz |
| Porcelain | 75% | 22.5 oz |
A full cycle includes fill time, drain time, and setup/cleanup. Hollow casting adds about 20 minutes of overhead; solid casting adds about 35 minutes because the slip must set completely in the mold.
New molds need 2–3 conditioning casts before they absorb at a consistent rate. The first cast often drains too fast, producing thin, uneven walls.
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Read our guide
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Last Updated: Mar 11, 2026
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