Peephole Plug

Useful plug in kiln firing to close kiln hole to raise temperature or doing reduction firing. This kiln plug is normally used in Excel kilns or other electrical and gas kilns. During initial firing remove all plugs to ventilate expel vapor impurities seen through peep holes as a haze. Thereafter after 20 minutes insert all plugs except the top most to raise temperature until maturity temperature and kiln shutdown. Plug the last peep hole for slow gradual cooling overnight before opening kiln. This avoid thermal cracking of ceramics caused by rapid cooling.