ARALDITE® AW 4752 / HARDENER HW 4753

• Excellent chemical resistance
• Temperature resistant to 100°C
• Bonds well to metals and treated surfaces
• Gap filling paste with controlled flow to allow good wetting without excessive capillary action.
• Easy 2:1 mixing ratio by volume

• The resin/hardener mix is applied with a spatula, to the pretreated and dry joint surfaces.
• A layer of adhesive 0.05 to 0.10 mm thick will normally impart the greatest lap shear strength to the joint.
• The joint components should be assembled and clamped as soon as the adhesive has been applied.
• An even contact pressure throughout the joint area will ensure optimum cure.

Typical Cured Properties

• Unless otherwise stated, the figures given below were all determined by testing standard specimens made by lap-jointing 114 x 25 x 1.6 mm strips of aluminium alloy. The joint area was 12.5 x 25 mm in each case.
• The figures were determined with typical production batches using standard testing methods. They are provided solely as technical information and do not constitute a product specification.

Average lap shear strengths of typical metal-to-metal joints (ISO 4587) (typical average values)

• Cured for 16 hours at 40°C and tested at 23°C.
• Pretreatment - Sand blasting and degreasing

Average lap shear strengths of typical plastic-to-plastic joints (ISO 4587) (typical average values)

• Cured for 16 hours at 40°C and tested at 23°C
• Pretreatment - Lightly abrade and alcohol degrease.

Lap shear strength versus temperature (ISO 4587) (typical average values)

• Cure: (a) = 16 hours/40°C (b) - Cure 24hours/23°C + 1 hour/80°C

Lap shear strength versus heat ageing (ISO 4587) (typical average values)

• Cure: 16 hours/40°C Test: at 23°C, 50% rh

Lap shear strength versus tropical weathering (ISO 4587) (typical average values)

• (40°C/ 92% RH), on aluminium, cured for 16 hours at 40°C and tested at 23°C.
• Pretreatment - Sand blasting

Pretreatment

• The strength and durability of a bonded joint are dependent on proper treatment of the surfaces to be bonded.
• At the very least, joint surfaces should be cleaned with a good degreasing agent such as acetone or other proprie- tary degreasing agents in order to remove all traces of oil, grease and dirt. Low-grade alcohol, gasoline (petrol) or paint thinners should never be used.
• The strongest and most durable joints are obtained by either mechanically abrading or chemically etching (“pickling”) the degreased surfaces.
• Abrading should be followed by a second degreasing treatment

Resin and hardener should be blended until they form a homogeneous mix.

Mechanical processing

• Specialist firms have developed metering, mixing and spreading equipment that enables the bulk processing of adhesive.

Equipment maintenance

• All tools should be cleaned with hot water and soap before adhesives residues have had time to cure.
• The removal of cured residues is a difficult and time-consuming operation.
• If solvents such as acetone are used for cleaning, operatives should take the appropriate precautions and, in addition, avoid skin and eye contact.

Typical imes to minimum shear strength

LSS = Lap shear strength.

Full curing (maximum Tg) requires the adhesive to be exposed to a temperature of at least 60°C.

The following times are typical options:

• 23°C – 24 hours minimum (not fully cured).
• 60°C – 2 hours. 80°C – 1 hour. 100°C – 20 minutes.
• Co-curing with phenolic impregnated filter media at 150 – 180°C is possible, but duration will depend on the requirement of the filter media (for example 20 minutes at 180°C).

       Storage

• Araldite® AW 4752 and Hardener HW 4753 must be stored at room temperature provided the components are stored in sealed containers.

       Handling Precautions

• Our products are generally quite harmless to handle provided that certain precautions normally taken when handling chemicals are observed.
• The uncured materials must not, for instance, be allowed to come into contact with food- stuffs or food utensils, and measures should be taken to prevent the uncured materials from coming in contact with the skin, since people with particularly sensitive skin may be affected.
• The wearing of impervious rubber or plastic gloves will normally be necessary; likewise the use of eye protection.
• The skin should be thoroughly cleansed at the end of each working period by washing with soap and warm water.
• The use of solvents is to be avoided. Disposable paper - not cloth towels - should be used to dry the skin.
• Adequate ventilation of the working area is recommended.