When installing bonded clamps to support metal tubing, which practice is correct?

When installing bonded clamps to support metal tubing, which practice is correct?

• A. remove paint or anodizing from tube at clamp location
• B. paint removal from tube after clamp installation to prevent corrosion
• C. paint or anodizing from tube at clamp location
• D. painting of clamp surfaces only

Answer: (A)

Bonded clamps rely on metal-to-metal contact to provide a reliable electrical bond (ground path) along the tubing. Any paint or anodizing at the clamp contact area acts as an insulator, increasing contact resistance and compromising the bonding path. That’s why the tube surface at the clamp location should be stripped of coatings so the clamp can make direct bare-metal contact. If coatings were left in place on the contact area, or if coating removal were attempted after installation, the bond would be weakened and corrosion or electrical issues could arise. Painting the clamp surfaces wouldn’t fix the problem and could also interfere with the metal-to-metal contact essential for bonding.

Bonded clamps rely on metal-to-metal contact to provide a reliable electrical bond (ground path) along the tubing. Any paint or anodizing at the clamp contact area acts as an insulator, increasing contact resistance and compromising the bonding path. That’s why the tube surface at the clamp location should be stripped of coatings so the clamp can make direct bare-metal contact. If coatings were left in place on the contact area, or if coating removal were attempted after installation, the bond would be weakened and corrosion or electrical issues could arise. Painting the clamp surfaces wouldn’t fix the problem and could also interfere with the metal-to-metal contact essential for bonding.