素材
Release Agent / Shelf Primer
Japanese: 離型剤
A material applied to the surfaces of shelves and molds to prevent glass from adhering. Typical examples include kaolin-based products (such as Bullseye Shelf Primer and HOTLINE) and BN (boron nitride) spray. The standard procedure is to apply three coats in three directions and allow the surface to dry for 24 hours.
Learn More
A release agent (also known as a shelf primer) is a material applied to the surface of shelf boards or molds to prevent glass from adhering to them during firing (Treatise §16.2, Chikaoka 2021, p. 156). It is also known as kiln wash. Main types: (1) Kaolin-based (HOTLINE SHELF PRIMER, Bullseye Shelf Primer, etc.)—diluted 1:5 with water before use; intended for bisque-fired ceramic molds and shelf boards; white powder-based; (2) BN (boron nitride) spray—intended for stainless steel molds and silver-plated products; stable at high temperatures; forms a thin film that leaves few mold marks. Note that kiln paper is also a method for release, but it is a different material.
Chikooka (2021, p. 156) application procedure (HOTLINE SHELF PRIMER): Dilute 1:5 with water → Apply multiple coats with a brush in three directions—parallel, perpendicular, and diagonal → Allow to dry for at least 24 hours → Smooth the surface by hand (lightly stroking it). Reapply only to the peeled areas each time; repaint the entire surface only once every few dozen applications. If the primer needs to be completely removed, physically remove it with sandpaper before reapplying. Improper application of the release agent (unevenness, peeling, or insufficient drying) is a direct cause of glass shelf adhesion (welding to the shelf), so it is important to check the condition of the release paper after each operation and to monitor it regularly.
Related Concepts
Release paper (kiln paper) · Kiln wash · Shelves (application to a four-zone design) · Slumping · Kiln casting · Kiln calibration
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.