Dextrin

Notes

Dextrin is a water-soluble carbohydrate derived from starch (usually corn or potato) and is used in ceramic slurries, glazes, and engobes as a temporary binder, thickener, and suspension aid. It is also used as a binder in ceramic bodies. Unlike glycerine, which remains liquid, dextrin forms a hard, brittle film when dry, making it useful for specific ceramic applications.

In ceramic slurries dextrin:
1. Is a binder, holding ceramic particles together before firing, adding green strength and dry hardness.
3. Is a suspension aid, preventing the settling of heavier particles.
4. Is an adhesion promoter, helps slurries stick to surface (especially vertical).
5. Burns out cleanly, decomposing at ~350–500°F (175–260°C) without residue.

Common Uses of Dextrin in Ceramics

Casting Slips: Helps maintain slip viscosity and reduces cracking in dried molds. Typical Addition: 0.5–2% (by dry weight of clay).

Engobes & Slip Decoration: Improves brushability and adhesion on leather-hard or dry clay on high ball clay mixes. Typical Addition: 2–5% (of dry mix). Water: Adjust for creamy consistency.

Sprayable Glazes & Underglazes: Acts as a binder to help glaze adhere when sprayed. Typical Addition: 0.5–1.5% (avoids clogging nozzles).

Pressing Aids: Mixed with dry clay powder to improve compactability.

Dextrin is used in adhesives, thickening agents, paper sizing, textiles, printing inks, substitutes for lactose, felt manufacture, and in pyrotechnics. You can make your own dextrin using instructions found on youtube.com. To find a commercial source, google the phrase "dextrin data sheet".

Related Information

Links

Oxide	Analysis	Formula	Tolerance

Typecodes	Additives for Ceramic Bodies Materials that are added to bodies to impart physical working properties and usually burn away during firing. Binders enable bodies with very low or zero clay content to have plasticity and dry hardness, they can give powders flow properties during pressing and impart rheological properties to clay slurries. Among potters however, it is common for bodies to have zero additives.
URLs	http://en.wikipedia.org/wiki/Dextrin Dextrin at Wikipedia
Articles	Binders for Ceramic Bodies An overview of the major types of organic and inorganic binders used in various different ceramic industries.
Materials	CMC Gum CMC gum is indispensable for many types of ceramic glazes. It is a glue and is mainly used to slow drying and improve adhesion and dry hardness.

By Tony Hansen
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