Damaged refractory castables are difficult to patch, because the dry material sucks water out of the patching material. The patching material has to be very sticky and must resist losing its liquid. we have some materials specially designed for patching.

Kerapatch Stainless is highly refractory material for hot patching which develops extreme strength. Supplied wet in buckets.

Phospatch is extremely sticky and can be poured into shuttering or smeared on. Supplied as powder and liquid kits.

Hollocast is an insulating patch material.

Keratuff are also insulating patching materials.

Crown patch is for glass kilns.

Fibre Plaster is a magic material for patching.

Alpatch is “cold setting” abrasion resistant material.

Fibre Plaster

Description: Aluminosilicate ceramic fibre in plaster form, supplied wet ready to use. Very easily applied to any surface


High temperature insulation

Heat shields

Burner cores


Thermal shock protection

Furnace hoods

Preheater lids

Ladle lids

High gas flow areas of fibre lined furnaces

Repair of cracks and joints

Protection of equipment

Protection of electrical cables

Upgrading of linings for thermal efficiency or faster cycle times

Repair of broken element holding lips

Sealing of kiln and furnace doors

Lightweight doors


Very low thermal conductivity: 0.2W/mK.

Electrically insulating

Very low density: 1.3g/cm³ wet, 0.7g/cm³ fired.

Low shrinkage: normally 12% but all taken up in the thickness of the layer, therefore no cracks.

Extreme thermal shock resistance.

Very low thermal mass.

High reflectivity.

Low permeability compared to fibre blanket or modules.

High reflectivity.

Rapid commissioning.

Excellent adhesion to all surfaces.

Minimal anchoring required.

Chemical composition:

aluminosilicate  55%
Fe2O3 < 0.1%
Alkalis  0.27%
Volatiles  45%


Installation: Fibre Plaster is supplied wet in well sealed plastic 10kg buckets. The wet density is normally 1.1g/cm³.

It can easily be thinned down with water or it ordered stiffer for tamping applications

Onto brick: Blow dust off and trowel on. Insulating firebrick or very porous surfaces; Rub a thin layer on very firmly before building up the profile.

Cables: No preparation required.

Ceramic fibre: Over fresh fibre, softening by water dilution usually helps.

Onto steel: Expanded metal, Mentex 72 or similar. Cut and bend a few strands backwards and tack them onto the steel so that the expanded metal sheet is about 5mm off the steel surface. Squeeze some Fibre Plaster through the mesh and then plaster over it to the desired thickness. Free standing structures; Use expanded metal as a skeleton.

Door seals: Plaster a narrow strip onto one surface, cover with fibre paper and close the door to press the Fibre Plaster into the exact thickness required.

Kerapatch Stainless

Description: Kerapatch stainless is a phosphate bonded chrome-alumina plastic material. Compared to conventional phosphate bonded chrome-aluminas, Kerapatch stainless has appreciably lower shrinkage, which results in superior structural integrity. It is supplied in soft plastic consistency, ready to use, in plastic buckets.

1. Induction furnace repairs.
2. Metal splash shields.
3. Abrasion resistant linings.
4. Sliding gate maintenance.
5. Long-life ladles and teapot ladles.
6. Runners and launders.
7. Water-cooled plate protection.

Composition: The aggregate is fused chrome alumina: a high purity synthetic alpha alumina polycrystalline aggregate with good temperature and chemical stability. The matrix is tabular alumina which has good bonding properties and thermal shock resistance. The phosphate binder develops high strength at 100ºC. A complex series of dehydration reactions follow, culminating in a very strong anhydrous bond at 400ºC. The ceramic bond develops from 1000ºC, and rapidly above 1200ºC. Before the phosphate becomes pyroplastic, the chrome-alumina bond is well developed. Consequently it has very high strength over the whole temperature range from 100ºC to 1800ºC.

Metal Protection: A sheet of expanded metal, heavy duty, such as Mentex 72, is bent and tacked onto the steel substrate such that it is positioned 10 to 15mm above the surface. The material is then pressed into this continuous anchorage and hammered tight. The thickness is typically 25mm. This system is used in the following applications:

1. The outsides of steel shells or structures which sometimes come into contact with pouring steel or ferroalloys. Eg.: Launder casings, especially upper edges. AOD hoods. Ladles with hoods. Bases of steel structures especially where silicon spillage is possible. Spincaster cover ends.
2. Where occasional metal flow is expected yet there is insufficient space to apply conventional refractories: Eg.: Tundish overflows. Continuous caster emergency launders. Teapot ladle spouts. Handheld purging lances.
3. Abrasion resistant linings where geometry is too complex for tiles. eg.: nozzles. 4. Abrasion resistant linings where the temperature fluctuation destroys tiles, Eg.: burner quarls, coke discharge chutes.

Where mechanical stresses are great, another system is used; Hexmetal reinforcing. The sheet of honeycomb metal is welded onto stainless steel plate and the keraplas packed into it. Each cell of the honeycomb is independently anchored, and the structure can withstand severe expansion and contraction and mechanical abuse. This system can be used on water-cooled copper panels etc.

Chemical analysis:

Al2 O3 82.0%
Cr 2O3 7.2%
Fe2 O3 1.7%
SiO2 4.0%
TiO2 0.02%
CaO 1.5%
MgO 0.2%
Na2 O 0.3%
K2 O 1.0%
P2 O5 3.4%
Total 101.5%

Packaging: 25kg plastic buckets, ready to install.

See also: Keramor chrome alumina mortars Refractory paint, green. Keraplas; Similar material with green chromic oxide. Alumina castables; Keratab and Rubycast. Injectable Rubyject.


Cellular insulation plasters are called Keratuff, as they are reinforced with fine water dispersible drawn zirconia-ceramic fibres.

Keratuff 1is similar to asbestos cement in strength and resilience.

Keratuff 2 has high insulation properties.


A patching material for hot surfaces and surfaces difficult to bond to. Phospatch is virtually impervious. It is totally silica free and immune to thermite reactions. It is very sticky and sets in 10 minutes.

Chemical analysis:

Al2O3    88%
CaO       4,5%
P2O5      7%


Maximum service temperature: 1780°C

Density: 2.6g/cm3

Max. particle size: 3mm

Mechanical properties: Phospatch has an exothermic setting reaction and expands slightly while setting. It sets in 10 minutes, and grips onto nearly all surfaces, even copper. Phospatch is not brittle; a hammer blow will make a slight dent rather than shatter it. Test cubes on cold crushing strength deform without breaking. The impervious structure gives immunity to chemical attack except on the surface. Strength increases with temperature, but the malleability changes to a more brittle rigid ceramic structure.


Protection of waffle coolers from molten metal  contact.

Patching of launders, flues, any hot repairs of furnaces.

Patching of surface contact line in aluminium furnaces to prevent thermite reaction.

Colour: Pure white.

Mixing: Mix 100 weight parts powder to 22 weight parts liquid gives a gives a good workability, but can be used from pourable to rammable without any problem. A lot of gas is evolved during mixing. Do not make large batches, as the exothermic reaction is self accelerating. Setting can be retarded by refrigerating the liquid binder.

Patches and castings can be heated up 20 minutes after  mixing.


5kg box repair kit, with mixing bowl and gloves.

10kg combined weight packs.

25kg packs, combined weight of powder and liquid.

25kg plastic bags of powder and 45kg polycans of liquid.

Shelf life: 3 years.

Development no. 39107

Claimer: This information had better be correct, because Dave Onderstall stakes his reputation on it.