7kg Tub of Batt / Kiln Wash (4kg Alumina Hydrate & 3kg Kaolin)
Separate packs of Alumina Hydrate and Kaolin Clay mixed to create Batt / Kiln Wash to protect your Kiln and it's surfaces. We provide this in a range of packs and quantities listed below with some including tubs for mixing (other tubs and sizes are available on other listings). We also sell a Batt / Kiln wash mix that utilises Zirconium Oxide in place of Aluminium Hydrate.
For comparison purposes - Typically if you purchase 'Alumina Batt/Kiln Wash' from elsewhere it will come pre-mixed in a pack and be either 50:50 or 40:60 Alumina Hydrate to Kaolin.
2kg batt wash mix - 1kg bag of Alumina Hydrate & 1kg Bag of Kaolin
2kg batt wash mix - 1kg bag of Alumina Hydrate & 1kg Bag of Kaolin - Includes 3 litre tub for mixing
3.5kg batt wash mix - 2kg bag of Alumina Hydrate & 1.5kg bag of Kaolin - Included 5 litre tub for mixing
4kg batt wash mix - 2kg bag of Alumina Hydrate & 2kg bag of Kaolin
7kg batt wash mix - 4kg bag of Alumina Hydrate & 3kg bag of Kaolin - Includes 10 litre tub for mixing
9kg batt wash mix - 5kg bag of Alumina Hydrate & 4kg bag of Kaolin
The principles of Kiln Wash’s:
A typical kiln wash is made up of Alumina Hydrate and Kaolin Clay. The idea is that because the Alumina Hydrate has a higher melting point than the temperature of the kiln any glaze that fall on to it can be easily removed because the thin layer of Alumina Hydrate prevented the glaze sticking to the shelf.
The Kaolin is present because on its’ own Alumina Hydrate is difficult to apply / brush on and becomes powdery when dry. To overcome this Kaolin is mixed in and, because it is clay and therefore sticky when wet it is easier to brush on.
Kaolin has a melting point of 1770°C and alumina oxide has a melting point of 2050°C, so it will not melt, even in a cone 10–13 Firing. These ingredients are called refractory because they are resistant to high temperatures.
A typical recipe is 50% Kaolin to 50% Alumina Hydrate. However some go to up to 60% Kaolin to 40% Alumina Hydrate, simply because Kaolin is the cheaper ingredient. However the issue with Kaolin is that it is both sticky and it shrinks. To overcome the first, the less Kaolin you use the better. To overcome the shrinkage you can if required Calcify the Kaolin by pre- firing it in a bisque bowl prior to use. Thus a better recipe can be 60% Alumina Hydrate, 20% Kaolin, 20% Calcified Kaolin. Any recipe you choose is based on your experience. We supply the ingredients separately so they can be mixed at your preferred ratio.