Metal finishing Q&As since 1989

-----

E-coating vs. galvanizing for security doors

Would like to know benefits of e-coating over galvanising. we e-coat presently but looking @ galvanising as an option for strength and corrosion resistance.we polyester powder coat @ our plant over our outsourced e-coating. any help or suggestions? have tests been done comparing the 2 methods (corrosion,strength and durability )

Jeremy Stewart
expandable security doors - Cape Town, South Africa
2004

---

Galvanizing involves applying a coating of molten zinc onto the parts, whereas e-coating is an organic coating similar to paint. Paint (or powder) on top of galvanizing, if done right, is the best finish there is because you get all the benefits of both. The advantage of galvanizing as an initial layer is that the zinc is a sacrificial coating that will protect the steel even if a scratch extends all the way to the substrate, whereas a scratch all of the way to the base substrate of an e-coated and powder coated part exposes that area to corrosion.

The advantage of e-coat is complete coverage. Because of the way the e-coat layer becomes an electrical insulator, after exposed areas are coated the power is automatically redirected to the deep recesses.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003