A poor weld ruins a perfect anode. Follow this datasheet protocol:
A new Zinc Anode 620 (6.2 kg) will deliver: zinc anode 620 datasheet
Formula:
The steel surface directly beneath a bolt-on anode must be cleaned to bare metal to ensure low electrical resistance. A poor weld ruins a perfect anode
Standard Marine (MIL-DTL-18001K) vs. High-Purity Soil/Freshwater Grade (ASTM B418 Type II). zinc anode 620 datasheet
Commonly ranges from 5.0 kg to 6.5 kg (approx. 11–14 lbs) depending on the core configuration. Net Zinc Weight: ~5.8 kg (12.8 lbs). Length: 300 mm (approx. 11.8 inches). Width: 150 mm (approx. 5.9 inches). Thickness: 30 mm to 40 mm (approx. 1.2 to 1.6 inches).