What steel screws and brackets do to aluminum

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knifer
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What steel screws and brackets do to aluminum

Post by knifer » 19 Sep 2016, 10:17

After gutting rotten interior discovered what iron brackets and screws do to aluminum ribs. Shiny due to wire cleaning.
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richg99
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What steel screws and brackets do to aluminum

Post by richg99 » 19 Sep 2016, 16:57

Electrolysis/galvanic corrosion. thanks for posting. richg99

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olefart
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What steel screws and brackets do to aluminum

Post by olefart » 22 Sep 2016, 01:00

question, would the aluminum brazing rods work to fix this corrosion?
:-k There are three kinds of people, those that count and them that don't. :popcorn:


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DaleH
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What steel screws and brackets do to aluminum

Post by DaleH » 22 Sep 2016, 08:02

olefart wrote:question, would the aluminum brazing rods work to fix this corrosion?
I think that they would.

FYI, just had a similar effect on a friend's boat and we cleaned the area, washed w/ vinegar, dried, primed w/ self-etching zinc chromate rattle can spray paint, and then topped with G-Flex flexible epoxy. As good as new (within reason). Epoxy products need to be painted to protect them from UV exposure.
#1) 1st tin rebuild, 18' Lund http://forum.tinboats.net/viewtopic.php?f=21&t=36583
#2) 25' Parker refurb from EMPTY hull http://www.classicparker.com/phpBB3/vie ... p?f=15&t=6
#3) 16' V-tin rebuild http://forum.tinboats.net/viewtopic.php?f=21&t=36465
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lckstckn2smknbrls
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What steel screws and brackets do to aluminum

Post by lckstckn2smknbrls » 22 Sep 2016, 09:24

olefart wrote:question, would the aluminum brazing rods work to fix this corrosion?
The issue with the brazing rods is if you over heat the aluminum you will cause more damage to the rib.
If you want to use the brazing rods do a lot of practice on scrap aluminum long before you take a torch to your boat.
1971 14' Ward's Sea King Jon Boat / 1983 Mariner 25HP

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pbw
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What steel screws and brackets do to aluminum

Post by pbw » 23 Sep 2016, 09:51

What is the hives recommendation on type of screws?
Last edited by pbw on 23 Sep 2016, 10:31, edited 1 time in total.
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richg99
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What steel screws and brackets do to aluminum

Post by richg99 » 23 Sep 2016, 10:17

????? What is the hives recommend on type of screws? ?????

Spellchecker must have done a number on you?

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pbw
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What steel screws and brackets do to aluminum

Post by pbw » 23 Sep 2016, 10:32

richg99 wrote:????? What is the hives recommend on type of screws? ?????

Spellchecker must have done a number on you?

Nope just one word...this is one big beehive sir.
PBW

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DaleH
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What steel screws and brackets do to aluminum

Post by DaleH » 23 Sep 2016, 10:52

pbw wrote:What is the hives recommendation on type of screws?
Uhhhhh ... tin boats ... don't use a screw if you can use an aluminum solid rivet (preference) or closed-end blind or 'pop' rivet (second ... provided the strength/shear requirements are achieved).

If not, through-bolting is your best strength, but INSULATE the SS fastener from the aluminum by using Tef-Gel seal or putting adhesive-lined heatshrink on the body of the bolt and nylon or other non-metallic washers under the head and nut of the fastener.

To do so otherwise it to create an environment for galvanic corrosion where the more noble stainless steel will cause an electrolytic reaction with the tin boat ... to where it will corrode away. This reaction is worse on saltwater boats as saltwater is an ideal electrolyte!
#1) 1st tin rebuild, 18' Lund http://forum.tinboats.net/viewtopic.php?f=21&t=36583
#2) 25' Parker refurb from EMPTY hull http://www.classicparker.com/phpBB3/vie ... p?f=15&t=6
#3) 16' V-tin rebuild http://forum.tinboats.net/viewtopic.php?f=21&t=36465
#4 Procraft SV14
#5) 16' Starcraft entirely NEW Transom Skins http://forum.tinboats.net/viewtopic.php?f=3&t=37548

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Skiffing
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What steel screws and brackets do to aluminum

Post by Skiffing » 25 Sep 2016, 17:26

knifer wrote:After gutting rotten interior discovered what iron brackets and screws do to aluminum ribs. Shiny due to wire cleaning.
What people said above - but give it an acid wash, then neutralize with ammonia / baking soda if you intend to prime / paint.

I don't think any aluminum "brazing" is structural. You need to weld, preferably TIG if you need a structural repair

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