EPOXY ADHESIVES

EPOXY is one of the most common general purpose, high strength adhesives the average person will have reason to use. Most true epoxies are two part and are available in various viscosities, or thicknesses to meet specific applications. This adhesive will give strong bonds on most materials with the proper preparation. Epoxy is ideal for metals, plastics, rubber, wood, glass and ceramics. Epoxy will fill the gaps between poorly fitting parts and can be sanded, cut and painted after curing.

MIXING:

General purpose two part epoxies generally require mixing in a 1:1 ratio or equal parts of both components. However, variation in temperature resistance and flexibility may require a different mix ratio. Check the manufacturers instructions. Carefully measure by weight or volume and mix well for the best performance of the adhesive. Do not mix more than can be used during the pot life of the adhesive. Do not use adhesive that has begun to set.

SURFACE PREPARATION:

Surfaces must be free from all contaminants such as soil, oil, grease, fingerprints, dust, and mold release agents. Wipe the surface with a solvent that will completely evaporate. Do not use a soap or other cleaner that will leave a film when dry. Roughen the surface when possible to increase bond strength. Special primers are available to improve the bonding of cured rubber.

APPLYING ADHESIVE:

Adhesive may be applied to one or both surfaces, and use only enough cover the surface and fill the gap as needed. Use a trowel or spreader for large surfaces. Assemble the parts in a way to avoid entrapped air. Some squeezing out of a little adhesive is a sign of proper assembly. Clamping is necessary only if assembly is subject to movement before achieving a handling bond.

CURING THE ADHESIVE:

Nearly all adhesives go through a curing process measured in minutes, hours and days to reach the full' bond strength. Some fast bond epoxies will grab and hold in a few minutes, however, they may take hours before achieving full bond strength. Most regular epoxies take hours at room temperature to reach a strong handling bond and 24 to 48 hours to reach full strength. Speed and strength of bond can be increased by baking or raising the bond temperature. A 24 hour curing time may be reduced to as little as one hour or less. Check with the manufacturer for recommended baking temperatures.

ADHESIVE CLEANUP:

It is necessary to clean up hands, equipment and any excess adhesive before it sets. Hot water and a detergent or a solvent will remove the adhesive. It is difficult to remove cured adhesive because of its resistance to solvents and other cleaning agents. Adhesive will soften at a temperature above 400~F and bond can be broken or adhesive can be removed by scraping. There are some commercial epoxy strippers available.

SAFETY:

Care must always be taken when using any chemical. Adhesives can be a danger to the eyes and skin. Epoxies are usually heavy or thick materials and not subject to splash or spilling, but care must be taken not to touch the eyes or wipe or spread the adhesive on your own or other people's clothing. Cured adhesive may be disposed as any plastic material. Adhesive containers must be tightly closed and kept from the reach of children. Follow any special instructions of the manufacturer. Industrial users are required to have Material Safety Data Sheets on hand.

SELECT EPOXY for high strength structural applications on metals, plastics or porous materials. It is ideal for combinations of different substrates. Works well in bonding rubber to other materials. These are not instant adhesives unless you can use heat. Many epoxies are available in dual cartridge dispensers that eliminate the mess and problem of mixing.