Keramicalia

Tel: +27 (0)11 412 3261 or +27 074 587 2728 Fax: +27 (0)11 692 1232
We manufacture specialised refractories and ceramics.

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. Electrical paint is also used for surface hardening.

Non-Wetting Paint for Aluminium is 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 ladies etc to protect them from dissolving in aluminium. Most used with scrim.

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.

Graphite Paints 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 coatingis for die casting moulds we also make graphite rubbing blocks for dry lubrication and graphite grease.

For fire protection we make Fire proof paint: a very hard rigid paint,

Archiecoat is a very coarse paint for insulation and some abrasion resistance.

We have developed a Fire proof paint for corrosion protection of the inside steelwork of furnaces. Its effectiveness is not yet proven.

We supply Intumescent Paint and intumastic paint, which contain raw vermiculite. They look like normal paint, but in a fire, the vermiculite expands to create thermal insulation.

For high electrical resistance at low temperature, we have developed Dielectric Paint. We also stock Glyptal.

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. Keralease was developed for pig casting machines.

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.

The last use of refractory paints is to increase emissivity or reflectance. The literature on thisapplication is highly contradictory and we do not know which paints work best, but we suspect their emissivity varies appreciably at different temperatures. (Wavelengths)

 

 

Alusmear

Description:

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.

Application:

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

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 600C to 1100C +60% water Off white Development no. P54903 Antiox 2 for 900C to 1300C +30% water Caramel brown Development no. P60500 Antiox 3 for 1200C to 1600C +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

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

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

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.

Composition;

Al2O3 80.5%
Fe2 O3 0.4%
ZrO2 4%
SiO2 0.06%
CeO2 15%
CaO 0.1%
Na2O 0.3%

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%
-75µm 84%

Packaging; 25kg plastic bags stretch wrapped on pallets.

Shelf life; Indefinite.

Packaging; 20Kg plastic lined drums.

Dielectric Paint

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%

Density:  2,7g/cm3

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.

Electrical Paint

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.

Density; 2kg/litre.

Coverage;
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.

Application;
Stir the bucket well.
Apply with a paint brush.
Clean brushes with water.

Packaging; 2kg, 10kg and 20kg plastic buckets. Ready mixed.

Fire proof paint

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

Flux Absorbent

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

Furnace Paint

Furnace Paint For painting on the inside of a furnace shell to protect it from corrosion. It contains phosphoric acid and aluminium orthophosphate. These phosphates react with the steel to form iron phosphides on the surface, which prevent oxidation, sulphur attack and rust from moisture. The paint is effective up to 400°C. Chemistry; Contains no organic materials and no conventional paint chemicals. Colour; Black. Thick paint consistency, may be diluted with water. Shelf life; not yet determined. Wash brushes with water. Coverage; About 2 m2 per kilogram.

Packaging; 10kg plastic buckets.

Development no. 10975

Glyptal

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.

PRODUCT DETAILS

Percent Solid by Weight                      50% ± 2

Viscosity @25°C   (MacMicheal), average   230cps

Solvent system                                  xylene

Specific gravity @ 25°C, average         0.98

Flash Point (Pensky – Martens)          60°F

Air-Drying Time, tack free, average      1 hour (1 mil dry film)

Typical Cured Properties

Dielectric strength – Dry(ASTM D115-55)   2500vpm

Dielectric Strength -24 hours In water     600vpm

Chemical Resistance                     

Oil (Transil)                      Excellent             

Water                              Good    

Salt water                        Good

Acid                                Good    

Alkali                              Fair

Data supplied by manufacturer

Development no. 127800

Graphite die coating

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.

Graphite Paints

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.


Appearance;
 A grey-brown paste.

Density;
1,5 kg/litre

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.

High Temperature Battwash

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.

Caution:

  1. Turbulence in gas fired kilns may spread batt wash onto glaze.
  2. If batts are turned over, clean all batt wash off the underside.

Chemical composition:

Al2 O3

59

.712%

Fe2 O3

0

.048%

ZrO*

39

.6%

SiO2

0

.148%

TiO2

0

.086%

CaO

0

.056%

MgO

0

.036%

CuO

0

.004%

Na2 O

0

.24%

U O

0

.032%

ThO

0

.008%

P2 O5

0

.02%

CeO

0

.02%

Organic

0

.1%

*Has traces of HfO

   

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 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 R887/lt (2017 price). Uses 3,3kg per m².

Both are based on the exfoliation of raw vermiculite.

Keralease

Description;   A liquid spray release agent for molten metals on steel/cast iron chills.

Composition;   Fused silica, graphite and binders.

Density;   1,22 kg/litre.

Application;   Mop, brush or spray.

Packaging;   1 cubic metre flowbins.

Development no. 138100

Mouldwash 18301

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.

Non-Wetting Paint for Aluminium

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.

Oxycoat

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 2017: R108/kg

Rigidiser

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