Galvanic Corrosion: Difference between revisions

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=Basics=
*Also referred to as dissimilar metal corrosion
*A Type of [[Corrosion]] that occurs between two dissimilar metals in presence of an [[Electrolyte]]
*Can Be Prevented By:
**Separation (Coatings/Material Choices, or if necessary a process that separates potential electrolytes from the materials, such as in [[Copper Clad Aluminum Wire]] )
**[[Sacrificial Anodes]]
**[[Impressed Current Cathodic Protection]]
=Marine=
*Silicon-bronze screws are for marine environments [https://www.woodmagazine.com/materials-guide/fasteners/drive-screws-that-dont-corrode]
=Protection=
*Rubber washer
*Epoxy around threads [https://www.eng-tips.com/viewthread.cfm?qid=457431]
*Permatex #3, Tefgel, Duralac, Lanocote are good coats for preventing galvanic corrosion [https://www.cruisersforum.com/forums/f55/does-loctite-protect-against-galvanic-corrosion-187978.html]
**Permatex #3 [https://www.amazon.com/Permatex-80019-12PK-Aviation-Gasket-Sealant/dp/B000HBM3QQ?th=1]
**Tefgel [https://www.amazon.com/Tef-Gel-TG-04-Anti-seize-Lubricant-Grade/dp/B00I8APPJU/ref=sr_1_2?gclid=CjwKCAiAleOeBhBdEiwAfgmXf6NJ67ASRsdNQpVAz5gQleoFjySU1X6BVAffTv2Nh4yL__qpVZkctBoCpe4QAvD_BwE&hvadid=616931742874&hvdev=c&hvlocphy=9023315&hvnetw=g&hvqmt=e&hvrand=7233038517835098175&hvtargid=kwd-2862344181&hydadcr=26612_11715053&keywords=duralac&qid=1675221600&sr=8-2]
**Lanocote [https://www.amazon.com/Lanocote-Corrosion-Control-4-Oz/dp/B0000AY4TI/ref=sr_1_1?crid=3G0861BV0TWAA&keywords=lanocote&qid=1675221646&sprefix=lanocot%2Caps%2C102&sr=8-1#customerReviews]
=Fasteners for Aluminum=
=Fasteners for Aluminum=
*This article says that stainless is best for screwing in aluminum, but must minimize corrosion such as rubber washer between screw head and aluminum sheet. It does not talk about contact between threads of screw and the aluminum - it appears the head is more important than the threads. [https://www.brikksen.com/home/page/blog?p=what-type-of-fastener-is-best-for-aluminum]
*This article says that stainless is best for screwing in aluminum, but must minimize corrosion such as rubber washer between screw head and aluminum sheet. It does not talk about contact between threads of screw and the aluminum - it appears the head is more important than the threads. [https://www.brikksen.com/home/page/blog?p=what-type-of-fastener-is-best-for-aluminum]
*Stainless and galvanized are ok with aluminum, as long as not salty environment [https://crossroadsgalvanizing.com/2020/07/27/galvanized-steel-in-contact-with-other-metals/]
*Stainless and galvanized are ok with aluminum, as long as not salty environment [https://crossroadsgalvanizing.com/2020/07/27/galvanized-steel-in-contact-with-other-metals/]
*This forum says epoxy coat screws for aluminum [https://www.finishing.com/421/40.shtml]


=Deck Screws=
=Deck Screws=
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*Deck screws are G185 or polymer coat [https://buildingadvisor.com/materials/decks-porches/deck-fasteners-connectors/#:~:text=STRUCTURAL%20FASTENERS%20AND%20CONNECTORS,be%20hot%2Ddipped%20galvanized%20steel.]
*Deck screws are G185 or polymer coat [https://buildingadvisor.com/materials/decks-porches/deck-fasteners-connectors/#:~:text=STRUCTURAL%20FASTENERS%20AND%20CONNECTORS,be%20hot%2Ddipped%20galvanized%20steel.]
*Polymer coat on deck screws is epoxy [http://www.ajaxco.com/articles/wholesale-deck-screws-top-3-corrosion-resistant-screws#:~:text=Epoxy%20coated%20steel%20screws%20have,wood%20and%20synthetic%20decking%20products.] or ceramic [http://fastenertips.fastenfinder.com/fasteners/examining-the-different-types-of-deck-screws-35/#:~:text=Ceramic%20coated%20screws%20can%20be,be%20the%20case%20with%20ceramic).]
*Polymer coat on deck screws is epoxy [http://www.ajaxco.com/articles/wholesale-deck-screws-top-3-corrosion-resistant-screws#:~:text=Epoxy%20coated%20steel%20screws%20have,wood%20and%20synthetic%20decking%20products.] or ceramic [http://fastenertips.fastenfinder.com/fasteners/examining-the-different-types-of-deck-screws-35/#:~:text=Ceramic%20coated%20screws%20can%20be,be%20the%20case%20with%20ceramic).]
*Triple Coated Deck Screws - two coats over galvanized screw [https://www.menards.com/main/hardware/fasteners-connectors/screws/deck-screws/grip-fast-reg-8-x-1-5-8-star-drive-tan-flat-head-triple-coated-exterior-deck-screw-25-lb-bucket/2303487/p-1444450197321-c-8929.htm] but not for marine.


=Pole Barn Screws=
=Pole Barn Screws=
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*Galvanized pole barn screws for aluminum [https://www.menards.com/main/hardware/fasteners-connectors/screws/pole-barn-screws/pro-grip-10-wood-grip-hex-drive-pole-barn-screw/galvanized2301503/p-1444448610897-c-8934.htm]
*Galvanized pole barn screws for aluminum [https://www.menards.com/main/hardware/fasteners-connectors/screws/pole-barn-screws/pro-grip-10-wood-grip-hex-drive-pole-barn-screw/galvanized2301503/p-1444448610897-c-8934.htm]


=Links=
=Wiring=
*Galvanic Corrosion with improperly installed [[Aluminum Wiring]] was (and to a certain extent still is) a MAJOR issue in Home Wiring
*If the proper fittings etc are issued there is no issue, but a direct copper-aluminum splice, or using switches/receptacles not [[Listed]] for one and/or the other etc can cause MAJOR issues, and as always with electrical a FIRE RISK
 
=Internal Links=
*[[Fasteners]]
*[[Fasteners]]
*[[Nail Gun]]
=External Links=
*[https://en.wikipedia.org/wiki/Galvanic_corrosion The Wikipedia Page on Galvanic Corrosion]
[[Category: Corrosion]] [[Category: Safety]]

Latest revision as of 22:24, 8 May 2023

Basics

Marine

  • Silicon-bronze screws are for marine environments [1]

Protection

  • Rubber washer
  • Epoxy around threads [2]
  • Permatex #3, Tefgel, Duralac, Lanocote are good coats for preventing galvanic corrosion [3]

Fasteners for Aluminum

  • This article says that stainless is best for screwing in aluminum, but must minimize corrosion such as rubber washer between screw head and aluminum sheet. It does not talk about contact between threads of screw and the aluminum - it appears the head is more important than the threads. [7]
  • Stainless and galvanized are ok with aluminum, as long as not salty environment [8]
  • This forum says epoxy coat screws for aluminum [9]

Deck Screws

  • Are deck screws compatible with aluminum? Some deck screws are polymer coated so they should work with aluminum if polymer doesn't srip
  • Deck screws are G185 or polymer coat [10]
  • Polymer coat on deck screws is epoxy [11] or ceramic [12]
  • Triple Coated Deck Screws - two coats over galvanized screw [13] but not for marine.

Pole Barn Screws

  • 1" menards - [14]
  • They are galvanized - [15]
  • Stitch screws - for bonding short lengths of metal [16]

Drill Point Screws

  • Compatible with treated, 3/4" long [17]
  • Sharp point - 1" - [18]

Aluminum and Galvanized Steel

  • Not compatible. Use rubber washer between.


Shopping

  • Galvanized pole barn screws for aluminum [19]

Wiring

  • Galvanic Corrosion with improperly installed Aluminum Wiring was (and to a certain extent still is) a MAJOR issue in Home Wiring
  • If the proper fittings etc are issued there is no issue, but a direct copper-aluminum splice, or using switches/receptacles not Listed for one and/or the other etc can cause MAJOR issues, and as always with electrical a FIRE RISK

Internal Links

External Links