Adhesive Bonding and Rivet Bonding
Structural adhesives
Two-part epoxy and urethane structural adhesives carry load and damp vibration. Bond strength depends more on surface preparation than on the adhesive itself: abrade, clean, and prime exactly as directed. Bond line thickness is controlled by glass beads in the adhesive, and clamping holds the joint until handling strength is reached.
Rivet bonding
Rivet bonding combines adhesive with mechanical fasteners. Self-piercing rivets pierce the top sheet and flare into the bottom sheet; blind rivets are set from one side; flow-drill screws form their own thread. Each fastener has a grip range and requires the correct die, punch, and tool setting. A rivet set too long or too short will not hold the joint.
Rules
- Use only OEM-specified adhesives and fasteners. Substitution is not permitted.
- Respect work time. Adhesive must be within its open window when the parts are joined.
- Verify the setting with a peel or destructive test and a visual check of every rivet head.
- Do not handle, move, or weld near uncured adhesive; observe cure times and temperature limits.
Worked example
On an aluminum-intensive body, a rivet-bonded joint is damaged. The reasoning: damaged rivets are drilled out without enlarging the hole, the same rivet part number and grip length are installed, adhesive is applied within its open time, the joint is clamped, and squeeze-out is confirmed. A longer rivet from stock would not develop the same clamp load.
Traps that cost marks
Wrong grip length; adhesive used past its open time; mixing brands of adhesive and primer; skipping surface preparation; assuming rivets alone equal the factory bond.