Refractory Paints and Coatings
Refractory paints have various functions, such as marking, anti corrosion, surface hardening, anti-wetting, electrical isolation, lubrication and release agents.
Refractory paints can be made in various colours for colour coding of ingots. Ingots can be marked with dabs of colour code to identify them and prevent missorting or misidentification. Our standard colours are white, black, brown, green, yellow ochre and red. The green paint is chrome oxide based and also used for anti-wetting. These paints delay oxidation of metals, but fail after a few months. A white oxidation resistant coating for steel called Oxycoat works a bit better, but does not air dry in humid conditions.
Oxidation protection paints for graphite are called Antiox.
Rigidiser is a colloidal silica paint for surface hardening of ceramic fibre modules, blanket and boards. We usually supply it with a blue dye so that you can guage the area and extent of penetration, but you can order it clear.
Non-Wetting Paint for Aluminium is a thick blue paint used for coating aluminium contact refractories, and some customers use it on tricky dies. Alusmear is used to coat steel and cast iron spoons, risers, automatic ladles, etc. to protect them from dissolving in aluminium. Mostly used with scrim.
Keracoat All is similar to Aluminium Non-Wetting Paint but silver and used on smoother surfaces.
Boron Nitride is used to coat aluminium refractories, particularly as lubrication for moving parts.
Electrical Paint is used mainly to coat iron-spotted or contaminated refractories in contact with electrical elements.It is non-conductive.
Electrically Conductive Paint is a black paint used mostly to start electroplating.
Graphite Paint is a friction free coating for sliding gates plates. 4808 is good, strong paint, others are made for ingot release e.t.c.
Graphite die coating is for die casting moulds we also make graphite rubbing blocks for dry lubrication and graphite grease. Graphite paint is a lubricant.
For fire protection we make Fire proof paint is a thick, hard, scratch resistant paint for protecting combustable surfaces like wood, cardboard or chipboard. It is a good oxygen barrier.
Archiecoat is a very coarse paint for insulation and some abrasion resistance.
We supply Intumescent Paint which which looks like normal paint, is a fire protection coating. When exposed to fire it foams up into a highly insulating layer.
KBS Coating is used for fire protection of cables.
Heat resistant aluminium paint is used on the steelwork of kilns and furnaces.
Glyptal is an electrical insulation resin used to insulate motor windings, induction coils and electro-plating equipment. For high electrical resistance at low temperature, Dielectric Paint , is similar, contains zircon, and is used for thicker coatings, e.g. busbars.
High Temperature Batt wash is used on kiln furniture to prevent wares from sticking. It is also used on chills for critical alloys.
Ceria Mould Wash is used on refractory moulds for casting matte etc.
Flux Absorbent is a paint based on absorbent alumina to prevent crucibles from sticking to their pedestals, prevent damage to components from a alkaline vapours and as extreme batt wash.
Waterproof Paint is a very highly elastic waterproofer.
Polystyrene paint is a solution of polystyrene and is used as a surface hardener at low temperature.
Zircon Paints are chemicaly resistant. We have three types: Zircon Paint, Zircon coating and Module Coating. The three are largely interchangeable.
The last use of refractory paints is to increase emissivity or reflectance. The literature on this application is highly contradictory and we do not know which paints work best, but we suspect their emissivity varies appreciably at different temperatures. (Wavelengths)
A paste for coating metal parts which come into contact with molten aluminium. It has various other applications where a hard ceramic coating is needed. It is a very sticky white paste which smears easily onto metal surfaces. It is normally used with Keratex fiberglass open weave. This netting helps with the application, keeps an even thickness and helps to overcome stresses of differential thermal expansion.
It contains a lot of colloidal silica and a small percentage of organic thickener. It goes stiff after long storage, and can be re-mixed to paste without adding any liquid. Re-mixing may leave some lumps, but the fiberglass sorts them out.
Smear a layer onto the surface to be protected. Press a layer of open-weave fiberglass into it and coat with a further layer until the desired thickness is reached. Use gloves to apply it, because the colloidal silica roughens the skin, and the Alusmear takes a while to wash off. Wash it off all skin and clothing before it dries because it STICKS! Dry the coating before immersing it in molten metal. 120°C is adequate.
You can dilute it and paint it onto crumbling brickwork to restore the surface.
Shelf life: Several years under cool storage conditions.
Packaging: 8 kg plastic buckets.
Antiox Paints for protecting graphite from oxidation. Graphite is inherently non-wetting, and it is difficult to find formulations which will adhere to graphite. They can only work if they are liquid, and they need to be very viscous. Graphite has a very low coefficient of thermal expansion, and most ceramic compositions tend to flake off on cooling. Since the viscosity of molten oxides decreases rapidly with temperature, it is easier to make protective paints for small temperature ranges. We therefore supply three materials for this application; Antiox 1 for 600°C to 1100°C +60% water Off white Development no. P54903 Antiox 2 for 900° C to 1300 deg C +30% water Caramel brown Development no. P60500 Antiox 3 for 1200°C to 1600°C +40% water Grey Development no. P78201 Antiox is not guaranteed to stick to all graphite surfaces. In some cases it helps to brush the surface lightly with a steel brush. If this still does not work, spray it lightly with an aerosol paint from half a metre away, to give a non-continuous coating, and then paint the Antiox on. Warm graphite works better than cold graphite generally. Viscosity and surface tension of the Antiox may be adversely affected by volatiles in the furnace atmosphere. Uses: Protection of graphite electrodes, induction furnace susceptors, graphite crucibles and vacuum furnace parts. Application: Add water and mix to form a paint. Brush it onto the graphite. Adjust the water content to find the ratio which gives best adhesion to your graphite. Warm graphite works better. Shelf life Indefinite.
Archiecoat, an aluminosilicate coating containing hollow ceramic microballons called cenospheres. The matrix is extremely fine, cohesive and dense, but the bulk of the volume is sealed air bubbles. The density is 1,7kg/l The coating is strong and abrasion resistant with good adhesion.
Installation; Mix with +20% water and paint on. The coating comes out about 3,5mm thick.
Applications: Protection of steel exposed to heat; Coating of moulds and chills, coating of slags pot,s protection from molten splash, shielding from welding splash damages.
Originator: Archie Holder
Development no. 94426
Packaging : 25kg plastic bags
Shelf life: 2years
Boron nitride has a plate like structure similar to graphite. (Another form of boron nitride has a diamond-like structure and is used for cutting tools).
It is a super smooth lubricant with extreme non-wetting properties towards molten aluminium. We use it on our aluminium dosing pumps, and others use it on Kerasic die casting moulds.
The maximum service temperature is 900°C.
It is very expensive, but only a few grams are required to give lubrication or non-wetting.
It is supplied as a water based suspension, and can be diluted with water before application by brush or spraying.
Ceria Mould Wash is based on three stable oxides with very high melting points; Ceria, CeO2 (Cerium oxide) 2700°C. Alumina,Al2O3 (Aluminium oxide) 2015°C, and Zirconia, ZrO2 (Zirconium oxide) 2700°C. All three are very stable and not reduced by molten metals. No compounds are formed between these three oxides, and therefore they have little tendency to sinter. The silicate addition is to prevent settling out from suspension, as the ides are all very dense.
Application; Mix with water and spray onto mould. It forms a very stable suspension at +70% water. No chemicals should be added.
Grading; +1mm 0%
-1mm +106µm 10%
-106 +75µm 6%
Packaging; 25kg plastic bags stretch wrapped on pallets.
Shelf life; Indefinite.
Packaging; 20Kg plastic lined drums.
A heavy duty electrical insulation paint. It is supplied very thick, otherwise it settles out very fast. Mix the whole bucket before using any. To thin it, use xylene. Clean brushes with petrol. The binder can resist 145°C. Below 145°C it is resistant to oil, moisture, acid and salt. A 1mm coating is tack free after 15 minutes.
Supplied as 2 parts paint plus 1 part xylene. Stir well, then add xylene to desired consistency.
Solids content: 90%
Ensure that the surface to be painted is dry.
Used around all electrical applications where equipment gets splashed with conductive materials.
Developed for superstructure around furnace busbars.
Development no. 127802
CLAIMER: The above data had letter be correct, because Dave Onderstall stakes his reputation on it.
Description; Arefractory coating with low electrical conductivity. Air drying. Consistency similar to household paints.
Composition; Fine reactive alumina bonded with colloidal silica, plus normal organic binders and suspension agents.
Melting point; About 1850°C.
Smooth surfaces; 250g/m².
Rough surfaces; 1,1kg/m² plus a second coat of about 500g/m2.
Uses; Covering iron spotted bricks in contact with elements. Reinforcing ceramic fibre blanket/modules. (Dilute with +100% water and apply about 4kg/mý.) Cosmetic coating of refractory structures. Increasing reflectivity of furnace surfaces. Sealing fine cracks to reduce gas leakage.
Stir the bucket well.
Apply with a paint brush.
Clean brushes with water.
Packaging; 2kg, 10kg and 20kg plastic buckets. Ready mixed.
This is a genuine fire proof paint, not a fire resistant paint nor an intumescent paint. It is totally inorganic. The only chemical released in a fire is water. The paint forms an air tight skin, preventing oxygen from getting to the substrate.
Fire proof paint is much harder than normal paint; it is difficult to scratch with a knife.
Fire proof paint is not as flexible as normal paint. It can be coloured with oxide pigments.
Fire proof paint is highly alkaline and similar to soap in its corrosive, skin contact and eye contact hazards.
Fire proof paint will stick to most surfaces, including whitewash, but not to oil contaminated surfaces.
Fire proof paint is slightly soluble in water. Clean paintbrushes with water.
Be careful of dry paint on the bucket; it is hard and razor sharp.
Development no. 94720
A coating based on activated alumina. It absorbs volatile chemicals from kiln atmospheres. it is used as a protective coating on kiln furniture to absorb fluxes which would otherwise attack and deform the kiln furniture. Once saturated it cannot absorb further fluxes and must be replaced. it is also used to prevent the anti oxidant glaze of clay graphite crucibles from welding them to their pedestals.
Packaging: 20kg plastic bags.
Shelf life: Indefinate.
Toxicity: completely inert as received, could become severely toxic after successful use.
Development no. 81300
GLYPTAL 1202 INSULATING VARNISH is a clear air-drying, insulating and finishing varnish designed for applications where oil, moisture, and acid-resistant coating are desire. This fast-drying, synthetic –resin - type varnish is often used as a final coat over other varnishes, giving hard glossy protective coating. GLYPTAL 1202 Varnish has excellent heat resistance and will operate as a finish coat at temperatures up to 145C on an apparatus that is not flexed. Although primary an air-drying varnish, the oil, moisture, acid and salt water resistance are greatly improved by baking. GLYPTAL 1202 has excellent adhesion to most materials. It has excellent dip tank stability where the proper thinners are used.
Data supplied by manufacturer
Development no. 127800
Graphite die coating is an ink like substance, water based, for spraying onto metal dies for release of metal castings. It is ultra fine and has no detectable influence on surface detail.
It can also be used to render surfaces electrically conductive. A thin layer painted onto glass gives a resistance of 5 ohms over 50mm, 2 ohms over 10mm.
We can also supply graphite paints for sand casting moulds, based on flake graphite, water based or alcohol based.
A high temperature lubricant based on natural flake graphite.
Principles; Graphite is a natural form of carbon consisting of layers of closely spaced carbon atoms, and a very large space between the layers. This gives it different properties if measured in different directions. It also allows the layers to slide relative to each other, and this makes it nature’s perfect lubricant. It is rather difficult to make a paint out of graphite, but it is possible. Graphite paint is a coating which is not fixed in place. It will move if something slides across it. It is pointless to try to get a graphite paint smooth. The paint will redistribute itself to fill voids. The important thing is to have enough thickness of paint to be able to fill voids and still cover the highest protrusions. The thickness of coating required is therefore a few microns on flat polished surfaces and several millimeters on rough refractory castings.
Applications; Lubrication of surfaces where refractories need to slide over each other or against steel. It was developed for sliding gate plates where the refractories are pressed against each other under very high pressure and the temperature reaches 1650°C. Used on doors, undercuts on very damaged casting dies, crack filling in almost unusable ingot moulds.
Composition; High quality natural Ceylon flake graphite with binders, carriers, wetting agent and biocide.
Maximum service temperature;
1000°C in exposed oxidizing atmospheres.
2000°C in reducing atmospheres.
A grey-brown paste.
Painting; Graphite Paint sticks to all surfaces except polyethylene. Preparation of substrate is only necessary if there is a lot of oil, grease etc. present. Small gaps in the coating are not a problem, they will get smeared over in use. Drying will be rapid on porous refractory surfaces, much like normal paints on steel. Sprayed Graphite Paint looks neat but works no better than very badly brush painted graphite.
Toxicity; All components are harmless and eye contact or accidental ingestion are no cause for alarm. Graphite paint poses no environmental threats or hazards. It is hover dirty, and you should wear overalls if applying large quantities, and if they get very dirty, wash them separately.
Packaging; 10 kg in plastic buckets. Brush painting will coat about 4mm thick. Add water to get the desired thickness appropriate to the surface roughness.
Track record; The formulation has changed little since 1988, and no application has been encountered where it has failed.
Shelf life; About 20 years. Add water if too thick to paint.
Development no. 4808
Claimer; The above data had better be reliable, as Dave Onderstall stakes his reputation on it.
Conventional batt washes adhere to batts if fired above 1100ºC, and need to be replenished after each firing. The build up later cracks off, leaving an irregular surface High temperature batt wash does not sinter at all, even under an oxy-acetylene flame. It does not need replacement until it has been physically rubbed off. A thin coating will prevent surfaces from sticking after firing. This is very useful when levelling props with clay, or for painting onto the mating surfaces of pot lids etc. It is also used on contact surfaces of doors and dampers when repairing kilns with Fibre Plaster. (Ask for kiln repair instructions.)
Mixing: 75 parts powder to 25 parts water. It is based on ziconia, which tends to settle out due to its extremely high density.
Turbulence in gas fired kilns may spread batt wash onto glaze.
If batts are turned over, clean all batt wash off the underside.
Under a hydrogen atmosphere at 1400ºC the Na2 O will vaporise, The organic material will decompose to gases and the CuO and Fe2 O3 will be reduced to metal. The SiO2 would give problems, but fortunately it is only present as 0,148%. We can increase the ZrO at the expense of Al2 O3 , to make the powder even more resistant to sintering, but its properties will make it slightly less easy to paint.
Intumescent paints are paints that foam up into a thermal insulation coating as soon as they come into contact with fire.
We make a white one which looks just like highest quality paint until it is heated. It costs R1 122 + VAT/lt (2019price). Uses 3,3kg per m².
Both are based on the exfoliation of raw vermiculite.
Mouldwash 18301 is an aluminosilicate scull release coating for hot metal ladles. It is supplied dry, and can be mixed with water to make a wash, spray or hand painting consistency. It has a smooth creamy consistency and good suspension properties. It is lime free, graphite free, phosphate free, harmless and non-toxic. It has low alkali content and has no fluxing action on alumino-silicate refractories. Mouldwash 18301 will not withstand the abrasion of a direct stream of metal.
Packaging; 25Kg thick transparent polythene bags.
Uses: Covering of all surfaces which come into contact with molten aluminium. It prevents adhesion of aluminium to all surfaces and prevents reaction of the molten metal with refractory linings. It prevents pick-up of iron etc. by the aluminium. It allows easy cleaning of ladles, launders and holding furnaces etc.
Description: The paint is supplied wet in plastic buckets, ready for use. The colour is blue when applied, and turns white after heating. It can be painted on with a brush or swab. It is chemically inert, harmless, non-irritant and non-flammable. It contains water as the only solvent. Clean the surface to remove loose particles and dust before painting.
Description: A refractory coating for oxygen lancing tubes. It is a thermosetting paint based on aluminium oxide.
Chemical analysis after drying to over 450°C;
Al2 O3 83 .3%
P2 O2 16 .7%
pH: 1 (highly acidic)
Density: 2,0 to 2,1 g/cm³
Application: Pipe must be completely clean of everything except rust or scale. Spray or paint on Oxycoat. Dry at 300°C. Application equipment must be completely free of other paints or solvents.
Handling: Although no problems have been encountered with skin contact, treat as strong acid and wear gloves.
Packaging: 20kg in 10litre plastic buckets.
Price 2019: R136/kg
Rigidiser A liquid containing colloidal silica particles. It is used to consolidate ceramic fibre blanket which is exposed to burner blast or high velocity gases. Conventional rigidisers are difficult to apply evenly, as they are transparent and you cannot see where you have painted or how much. We therefore add a blue dye which burns out later. If you need more protection, use our electric paint. If you need extreme protection, use our Fibre Plaster. Rigidiser is also used to strengthen ceramic fibre boards, e.g. when elements are pinned onto it.
Shelf life : ± 5years. Do not allow to freeze.
Packaging : 6kg in 5litre bottles 30kg in 25 litre polycans
Development no. 11418
A thick viscous white paint for reliable waterproofing. One coat is about 1mm thick. Use 2 coats for complete security. A coat takes about 6 hours to dry.
A coat can be stretched to 2½ times its length without tearing!
Guaranteed for 10 years.
Resistant to acids and alkalis. It is a “green” product with no harmful chemicals or solvents.
Clean hands and brushes with thinners.
2019 price: R64/Kg + VAT
Packing: 20Kg Buckets
Development no. 157801
Description; A zircon paint, water based, supplied wet in buckets
Sealing porosity of furnaces and brickwork and ceramic fibre.
Foundry mould coatings.
Protection of ceramix fibre in high velocity gas flow.
Preventing adhesion of metal splash.
Reducing splash from cardboard sampler tubes etc.
Surface hardening of insulation materials.
May be used in contact with molten metals.
Reducing wettability of refractories.
Reducing alkali attack on crucibles.
Mix it before application to get it all in suspension.
On very smooth surfaces it may crawl; add a few drops of dishwashing liquid to prevent this.
Colour; Light brown.
Density; 2,0 g/cm³
Chemical analysis on dry basis;
Packaging; Plastic buckets; 20kg.
Development no. 72812