Keramicalia

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

Adhesives

Below 100°C there are hundreds of adhesives which work. Between 100°C and 250°C certain silicones can be used. Above 250°C it becomes difficult. The biggest problem is the difference in thermal expansion between the materials to be glued. Metals expand more than ceramics. When gluing ceramic to metal, the adhesive generally works at high temperature and comes loose when the structure is cooled down. When gluing ceramic tiles to a steel shell, a blob of glue in the centre often works better than a continuous layer, as the thermal expansion mismatch is reduced over the smaller area.

Air setting glues cannot be used between two impervious surfaces. Heat setting glues are not strong until heated. Cold setting glues are supplied as powder and liquid.

Ceramic adhesives normally set hard and rigid. In some cases we can formulate pyroplastic glues which are partially molten at high temperature, but they generally lose volatiles in time and become rigid.

When in doubt, give us a full description of your application with regard to

  1. What materials are to be glued?
  2. Arrangements, e.g. ceramic inside a steel pipe.
  3. Temperature
  4. Thermal cycling
  5. Must it be gas tight?

Shorten Glue is a very fine glue with a toothpaste consistency, supplied in mastic tubes, which can be injected into sub millimeter spaces over fair distances. Air setting.

High Temperature Fibre Glue is used from 1200°C to 1600°C.

Water Based High Temperature Tile Grout is for alumina wear resistant tiles at temperatures above 250°C. It can work up to 1600°C, but the steel shell is ruined long before that.

Kerastick is used for foundry moulds and ceramic fibre, and so is Core glue.

Brickstick is used for instant holding of heavy bricks upside down, mainly in construction of rotary kilns. The brick forced into position by a hydraulic ram, and stays in place. With conventional mortars, the bricks have to be held in place until the key is inserted.

In some applications mastics are used as adhesives. Kerasil Mastic is popular.

In other applications plasters are used, such as Keratuff 1 andKeratuff 2 .

For kiln bricks, repairing broken, lips Fibre Plaster is used.

Cold setting glues are used between impervious surfaces. Hardcast Fine is used by many thermolcouple manufacturers. It sticks well to glass. Most chemical variations can be made based on Versimould technology. (See Versimould on www.keramicalia.co.za/versimould) Phospatch fine can also be used. It’s unique property is that it is the only ceramic that sticks to copper.

Graphite glue is used to repair clay Graphite crucibles for melting zinc or aluminium.

We make a polystyrene glue, because solvent based adhesives destroy polystyrene. The trouble is you can’t hot wire cut it through the glue. We have lots of tricks for gluing various plastics and bonding ceramic to plastic.

Electricast Glue is used for joining electrical ceramic components.

 

Water Based High Temperature Tile Grout

Description:  A high density plastic alumina refractory. It has high strength and abrasion resistance and good adhesion generally.

Applications:   Mainly used to glue alumina tiles into pipes which are to be used at high temperatures. The maximum service temperature is 1700°C.

Installation: Supplied as powder, to which +12 to+13% water must be added for a stiff putty consistency, or more water for a softer embedding consistency. Typically you place far too much in a corner between tiles, then push and wiggle the next tile into place as tightly as you can, pushing out a large amount of excess material. Scrape the excess material into the corner for the next tile. It sets in around 2 to 3 hours.

Chemical Analysis:

Al2 O3

89.0%

Fe2 O3

0.1%

SiO2

2.0%

CaO

9.0%

Na2 O

0.3%

P2O5

0,07%

Colour: White

Maximum particle size: 1mm
Packaging:  25kg plastic bags
Project no. 1396

Claimer: The above data had better be correct because Dave Onderstall stakes his reputation on it.

Fibre Plaster

Description:

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

Applications:

High temperature insulation

Heat shields

Burner cores

Chimneys

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.

 

Properties:

Very low thermal conductivity; 0,2W/mK.

Electrically insulating,

Very low density; 1,3g/cm³ wet, O,7g/cm³fired.

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 comissioning.

Excellent adhesion to all surfaces.

Minimal anchoring required.

 

Chemical composition:

aluminosilicate 55%

Fe203 < 0,1%                                     

Alkalis O,27%

Volatiles 45%

Installation:    

Fibre Plaster is supplied wet in well sealed plastic 10kg buckets. The wet density isnormally 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 builing 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.

 

Kerasil Mastic

Kerasil mastic is supplied wet in mastic tubes, ready to use. It has a soft consistency and is almost fluid. It coats very well and easily to all surfaces, and sets very hard and strong. It sets rigid and permanent, and should therefore be used with discretion in moving structures. It can be injected deep into cracks and joints, without being sucked dry by the surrounding material.

As a brick mortar the soft consistency allows thin joints to be made. As a fibre module cement it gives a considerably larger contact area than normal mortars. Exposed surfaces normally become smooth and exhibit no cracking. A thin dry film develops rapidly on the exposed surface, so bonding should be performed quickly.

Kerasil mastic is 90% pure silica and can be used up to 1300°C. It is light brown when wet, and becomes almost white when fired.

Packaging is in mastic tubes, with a nozzle. The nozzle must be rmoved and the tip cut off. Then the tube is placed in a hardware store gun (as used for silicone sealants) and the nozzle replaced. Cut the nozzle for the appropriate size to insert in the crack or flange, and squirt it in.

Wash hands well after contact and apply a moisturising cream.

Setting is slow at ambient temperature and rapid at high temperature.

Keratuff 1

DESCRIPTION: Keratuff is a structural refractory insulation. Insulation materials are normally only usable as a backing or with some kind of structural support. Keratuff has sufficient strength to be a free standing structure.

APPLICATIONS: Precast pizza oven roofs, crucible furnace lids, heat shields, splash boards, aluminium launders, burner shields.

THERMAL CONDUCTIVITY:

200°C 0,19W/mK
4000C 0,23W/mK
6000C 0,25W/mK
8000C 0,28W/mK
1000°C 0,31W/mK


MAXIMUM SERVICE TEMPERATURE: 1200°C. Keratuff melts between 1200°C and 1300°C. Shrinkage at 1200°C is 1,7%.

DENSITY: 1,0 dry, 0,85 fired.

STRENGTH: 23MPa at 110°C, 6MPa fired 1200°c.

COMPOSITION: Contains Litefill and Hollofill synthetic aggregates, and zirconia containing ceramic fibres. 53/o alumina.

PREPARATION: Add +40 to +50% water to the powder, mix well and apply it. It can be vibration cast at +40% water, +50% is easier to apply by trowelling. Water content is not critical and need not be measured. Extensive mixing and trowelling improves the fibre dispersion and improves strength. All particles are less than 1mm diameter. Setting time is about one hour.

PACKAGING: 10Kg in thick polythene bags.

PILOT PLANT CODE: OEV.

Keratuff 2

DESCRIPTION: Keratuff 2 is a structural insulating refractory. Insulation materials are normally only usable as a backing or with some kind of structural support.Keratuff 2 has sufficient strength to be a free standing structure. It has low permeability and is easily machined or cut when dried or fired.

APPLICATIONS: Electric kiln walls and element holders, crucible furnace lids, heat shields, masonry protection in charcoal ovens, aluminium launders, burner shields, machined components.

THERMAL CONDUCTIVITY:

200°C 0,2W/ mK
4000C 0, 2W/'mK
6000C 0,231W/!mK
800°C 0,28mK


MAXIMUM SERVICE TEMPERATURE:  1230°C.  Shrinkage at 1200°C is 1,91.

DENSITY: 0,8 g/cm3 dry.

STRENGTH:  6 MPa at 110°C, 6 MPa fired 1200°c.

COMPOSITION: Contains Litefill and Hollofill synthetic aggregates and zirconia containing ceramic fibres.

PREPARATION: Add +40-5O1 water to the powder, mix well and apply it.

It can be vibration cast at +40% water. Water content is not critical and need not be measured.

Extensive mixing and trowelling improves the fibre dispersion and improves strergth. All particles are less than 1mm diameter. Setting time is about one hour.

COLOUR: Grey. Yellow when fired 1200°C.

PACKAGING: 10Kg in thick polythene bags.

PILOT PLANT CODE PGK.

Shorten Glue

An adhesive or sealant with extreme penetration properties.It was developed for anchoring wires in 2mm diameter ceramic tubes.It will penetrate a 1mm hole to a depth of at least 100mm.Can be used as a mortar for ultra thin joints.

Chemistry:Alkaline aluminosilicate.

Maximum particle size:0,3mm

Consistency:Soft paste with a low yield value but no flow without pressure.Similar to soft toothpaste.

Colour:Grey.

Set:Air setting, very hard.

Strength: Will break brick before breaking bond.

Packaging:Mastic tubes, 540grams, like hardware store silicone sealer.Boxes of 15 tubes.

Shelf life:About 8 months.

Development no.  16929.

Graphite Glue

Description: A glue for repairing clay-graphite crucibles.

Application: Mix powder and resin to desired consistency. Apply to both surfaces, rubbing it in well. Stick the surfaces together as tight as you can. Smear a thin layer over the joint. Allow to cure for 24 hours or heat it up to speed up hardening.

Maximum service temperature: 1000°C exposed to air, higher under reducing conditions or covered by non-ferrous metals.

Repair is very effective for low temperature metals, for aluminium it should be used in conjunction with scrim and Alusmear. Not recommended for use over 900°C

Development no.1300

High Temperature Fibre Glue

An extremely dense glue for bonding ceramic fibre and fibre board at high temperatures, or for protective coating.
Density:     wet: 2,75/cm3.
Color:   white.
Shrinkage:   not measurable.
Set:  heat setting.

Chemical  analysis      81% alumina
Al2O3        80,4%
Cr2O3        0%
Fe2O3        0,06%
SiO       1,0%
CaO        0,3%
MgO        0,6%
Na2O        0,3%
P2O5        8,2%
L.O.I        10%
Packing : supplied wet in plastic buckets, any quantity.
Shelf life: 12months
Development no. 33024

Electricast Glue

A glue with extremely low electrical conductivity, based on zirconium silicate.

Mix 100 weight parts powder with 12 weight parts water.

It will appear to be far too dry. Carry on mixing for 2 minutes and it will become a soft, VERY STICKY paste. Place on the bonding surface and squeeze the parts together. It grips in seconds.

Wet material must be used within half an hour. Make small batches, 1kg maximum, otherwise hand mixing is difficult. Full chemical set takes about 24 hours.

Development no. 77038

Claimer: The above information had better be correct, since Dave Onderstall stakes his reputation on it.