Aloha, fun & authoritative answers -- no cost, no registration, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Adver-
tise
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub  Where the
world gathers for metal finishing
Q&As since 1989



-----

Sacrificial anode on an above-ground steel structure?




Hello;
I've been trying to figure out if a sacrificial anode can be used on an above-ground, static steel structure to help prevent rust. I've been reading that sacrificial anodes are used in situations where dissimilar metals are surrounded by an electrolyte like water or soil, which is different from a steel structure sitting on the ground. Our products are A36 HRS P&O;, then powdercoat painted.
Each painted member is bolted together using a SS bolt/nut.

Inevitably, the painted surfaces get scratched and start to rust. Is it practical to use a sacrificial anode on the structure to prevent the rust? What if I ran a grounding strap from the steel structure into the ground, and close by it I buried a sacrificial anode, and ran a strap from the anode up above the ground and connected it to the steel structure? Would that simulate the electrolyte environment for the circuit to be completed, and then the anode would corrode instead of the steel structure rusting?
Thanks for reading,

-Eric

Eric Golden
skate park ramps - Joplin, Missouri, USA
2003


There are experts on this subject, and hopefully one of them will answer you. In the meanwhile, I will mention the general principle that galvanic corrosion and galvanic protection require both a metallic path and an ionic path (wet path). Galvanic protection obviously works on ships; it fails on cars because the vulnerable metal of the car can't be connected to a sacrificial anode by a constantly wet ionic path.

The containment structures of at least some nuclear power plants are protected with sacrificial anodes, however. Apparently there are some areas that are wet enough that the protection works, and when one is working with a nuclear power plant the cost of sacrificial anodes is probably insignificant.

What you probably want to consider, however, is the use of galvanized metal. That way, the protection offered by the zinc is right where it's needed, and galvanizing does deter rust.

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




(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

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


Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"