|FEVICOL SH* OR EQUIVALENT *SYNTHETIC RESIN ADHESIVE WATER BASED WHITE GLUE.||FEVICOL SPEEDX* OR EQUIVALENT *SYNTHETIC RESIN ADHESIVE||FEVICOL SR 998* OR EQUIVALENT *SYNTHETIC RUBBER BASED ADHESIVE CONTAINS SOLVENT.||FEVICOL SRXPRESS* OR EQUIVALENT *SYNTHETIC RUBBER BASED ADHESIVE CONTAINS SOLVENT|
|1) SURFACE||Should be properly leveled||Should be properly leveled||Should be properly leveled||Should be properly leveled|
|2) COATING||Should be on both the surfaces||Should be on both the surfaces||Should be on both the surfaces||Should be on both the surfaces|
|3) A) HUMIDITY||Should be used in normal humidity||Normal humidity||Can be used in higher humidity||Can be used in higher humidity|
|3) B) HUMIDITY MORE THAN 80%||Should not be used||Should not be used||Can be used||Can be used|
|4) PRESSURE USED||Under Pressure||Under Pressure||Under Pressure||Under Pressure|
|6 – 8 Hours||2 Hours||30 Minutes||20 Minutes|
A) The surfaces to be bonded should be properly leveled, free from oil/grease/dust and excess moisture. For best results roughen the surfaces to be bonded.
B) INSUFFICEIENT AMOUNT OF ADHESIVE ON EITHER OR BOTH OF THE SURFACE TO BE BONDED: When ready for bonding, the spread film of most contact adhesive will exhibit a uniform semi-gloss appearance over the entire surface of the material to be bonded. Marked variation in appearance will generally indicate an improper or non-uniform adhesive spread. The substrate can generally be seen more readily through those areas where insufficient adhesive has been applied. If this occurs, recoating the surfaces should achieve a uniform coating. Double coating the edges with adhesive is advisable because of the higher porosity of the substrate edge.
C) INSUFFICEINT BONDING PRESSURE To insure intimate contact necessary for an adequate bond, sufficient pressure should be applied over the entire area using as much pressure as possible without damaging the assembly .Pinch rollers (rotary press) and heavy weighted rollers are ideal. Hand pressure rolling is adequate provided the operator exerts maximum pressure by means of a two handled or single long handled roller. The rollers should be of steel or hard solid rubber (50 – 80 durometer) and not over 75 mm (3 inches) wide. Hand rolling should be done from the center to the edges to ensure the removal of all air bubbles. The edges should be rolled twice.
D) BONDING WHEN ADHESIVE SURFACE ARE OVER-DRY OR UNDER-DRY Care should be taken to follow the manufacturer's recommendations concerning the allowable tack range of adhesive. Of assembly's made before the adhesive is dry or after the allowable open tie is exceeded, an unsatisfactory bond may result.
E) BONDING OF SURFACE UNDER 21 deg. C (70 deg F) Unless otherwise indicated by the manufacturer, the temperature of the gluing area and all materials should be 21 deg. C (70 deg. F) or above.
F) BONDING OF SURFACE WHERE HUMIDITY IS TOO HIGH Experience has shown that when the relative humidity is above 80 percent at temperatures of 21 deg. C (70 deg. F) or lower, moisture may condense on the surface during drying (known as "blushing") and will prevent an acceptable bond. Hot spray or forced air drying may be used to help prevent this condition.
G) IMPROPERLY PREPARED OR DIRTY GLUING SURFACES: The surfaces should be clear, dry and free of oils or other contaminants, such as dust, loose paint particles, and so forth. The adhesive film should have full contact with surface to which it is applied in order to give maximum adhesion.
H) ADHESIVE NOT AGITATED OR STIRRED THOROUGHLY The adhesive should be stirred or agitated before use. This is particularly necessary with large containers.
I) FIELD BONDING OF OVERSIZED SHEETS It is recommended that the maximum sheet size used for vertical field application be limited to 610 X 2400 mm (2 X 8 feet). If larger panels are required, these should be fabricated in the shop.
J) STRESS CRACKS When cut-outs are to be made for switchboards, plug points, eyeholes, etc. at 90 degree, the normal practice is to make the cut-out by just cutting the sheet. But this is not the right method. If cut-outs at 90 degree are to be made, a 3 mm diameter hole should be drilled at the four corners of the cut-out area before cutting the sheet. If this method is not followed, stress cracks will develop from each corner of the cut-outs. These cracks will gradually spread in various directions.