素材
Kiln Paper / Shelf Paper
Japanese: 離型紙
Fireproof paper laid on the shelf. Prevents glass from adhering to the shelf. Disposable; it turns to ash and decomposes after firing. Used as an alternative to or supplement for a release agent (kiln wash).
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Release paper (Kiln Paper / Shelf Paper) is a fire-resistant fiber-based paper laid on shelf boards; it serves as a release agent to prevent glass from fusing to the shelf boards during firing (Treatise §6.3, Chikaoka 2021, p. 156). The fiber material is typically ceramic fiber (alumina-silica fiber); after firing, it remains as a light layer of ash adhering to the back of the glass but can be removed by washing with water. It is recommended to use a new sheet each time (Chikaoka 2021, p. 169, Q&A), as reuse carries the risk of poor release or surface contamination. It is used in nearly all situations where glass is fired on a shelf, such as fusing, slumping, and fire polishing.
An important characteristic of release paper is that, when heated, the organic binder components (found in most products) may burn, potentially creating a localized reducing atmosphere. In particular, during the firing of lead-based glass (such as Gaffer Casting Crystal), this localized reducing atmosphere carries the risk of inducing lead-crystal blackening. Furthermore, while the thickness of the release paper (approximately 1–3 mm) does not affect the calculation of effective thickness, its insulating properties slightly delay heat transfer from the shelf to the glass. On the other hand, when placing release paper in a slump mold (for sagging, etc.), it is important to lay it flat, as wrinkles in the paper may be transferred to the back of the piece.
Related Concepts
Release agent (kiln wash) · Lead crystal blackening · Slumping · Fire polish · Effective thickness · Four zones
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.