Henkel 681

Surface Preparation

The 681 adhesive requires no surface preparation on most metal, ferrite, and glass surfaces. However, for optimum bond strength on metal parts the surface should be washed with a solvent or cleansing solution, abraded with an abrasive pad, and then rinsed with a solvent or cleansing solution. Glass surfaces should be cleaned with a commercial glass cleaner before bonding. Painted surfaces should be abraded lightly and then wiped clean.

Application

Bondmaster's Equipment Group, has a complete line of industrial dispensing equipment to dispense the 681 in magnet bonding applications. Equipment is available to dispense the adhesive through Bondmaster's unique External Mix dispensing process. The External Mix Dispensing System is a technology that results in high performance without the use of a static mixer. This allows the use of the adhesive in high-speed production without having to change static mixers frequently. The External Mix technology also provides the user with a higher performance than conventional bead-on-bead systems.

In addition to standard equipment, Bondmaster offers custom dispensing equipment, designed for your specific application and production requirements. Contact your local Bondmaster sales representative for more equipment information.

Mixing

Five grams each of Bondmaster 681 Part A, Part B, and mixed adhesive were enclosed in a container with a conductive copper surface. The resistance of the copper surface was measured after a 24-hour and 240- hour exposure at temperatures of 50°C (122°F) and 150oC (302°F).

Bondmaster 681 Part A & Part B should not be mixed in large quantities, as a vigorous chemical reaction will occur generating a significant amount of heat and vapors.

Curing

Exposure to air will inhibit the cure of all acrylic adhesives. Because of this inhibition, the exposed surface of any mixed adhesive squeezed outside the bondline will remain tacky for a few hours. Only the cure of the exposed surface is inhibited, not the adhesive in the bondline.

Clean-Up

Unreacted Part A & Part B can be cleaned up using acetone, isopropanol, or MEK.