| Surface Preparation |
| 1. |
Roughen
surfaces with 150 to 320 (US) grit abrasive. |
| 2. |
Rinse
off dust residue. |
| 3. |
Clean
with an alkaline cleaning solution or 70% isopropyl alcohol/water
mixture to degrease. |
| 4. |
Rinse
in deionized water. |
| 5. |
Dry at
100°C (212°F) for a minimum of one hour. |
| 6. |
Apply
adhesive or primer as soon as possible after cleaning. |
| |
|
| Adhesive Application |
| 1. |
Apply
in accordance with manufacturers instructions. Epoxies, urethanes and
cyanoacrylates all perform well. |
| 2. |
Apply
uniform pressure until adhesive is set. Apply heat as required by the
adhesive supplier. |
| 3. |
Silane
coupling agents can be used as a primer to improve adhesion if
necessary. These are especially beneficial when bonding in high
humidity environments. |
| |
|
| Joint Design Hints |
| 1. |
Design
joints for pure shear with uniform stress distribution across the
joint. Cleavage and peel stresses due to bending should be avoided. |
| 2. |
Lap
Joints |
| |
—
Simple lap joints can result in cleavage and peel under load. |
| |
—
Joggle laps improve the stress distribution across the joint. |
| |
—
Double butt lap or double scarf lap joints further improve resistance
to bending. |
| 3. |
Angle
Joints |
| |
— Grooved joints (dado joints) offer good resistance to peel
and cleavage. |
| |
—
L joints are fair. |
| |
—
T joints have good resistance to non-uniform joint stresses. |
| 4. |
Butt
Joints |
| |
—
Straight butt joints have poor resistance to cleavage and should be
avoided. |
| |
—
Tongue and groove or scarfed joints are superior. |
| |
|
