Re: LRO: Re: corrosion issues/shipfitters disease/sil

From: Peter Ogilvie (konacoffee2@hotmail.com)
Date: Wed May 16 2001 - 00:56:25 EDT

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    Everyone should place insulating material between the tub mounting tabs and
    the tub. My well oxidized parts truck had neat square pieces oxidized to
    oblivion from the tub where the cross member tabs touched. My new/old 109
    tub had significant corrosion where the front frame mounting tabs touched
    the aluminum. Even had a little corrosion on the tub, under the mounting
    tabs, on my absolutely rust free 109. Don't know why this area is so prone
    to progressive corrosion. It could be that the tub racks minutely in use
    and constantly scrubs off the insulating oxidation exposing fresh metal to
    corrode. Its also a good trap for water. Another place I've noticed
    corrosion is the fender mounting bolts on the top of the fender at the
    bulkhead. Probably because its level and any moisture rolling off the
    bulkhead and/or hood ends up there.

    Stainless will work okay if you insulate the head or washer from the
    aluminum. If you live in salt water or the north central and north east, I
    wouldn't use anything but galvanized and insulate that. A dissimilar
    fastener touching the aluminum will corrode around the shaft thus insulating
    itself from the aluminum and ending further corrosion. Its mainly when you
    have constant addition of electrolyte like salt water or salt roads that
    cause problems. That's because the electrical bond gets continually renewed
    and corrosion is continued and/or accelerated by the salt.

    FWIW The farther apart metals are on the galvanic scale, the more galvanic
    corrosion will occur. From memory, Zinc (galvanizing) is right next to
    Aluminum. Corrosion between galvanized fasteners and the
    Birmabright should be minimal. Find a source of galvanized flat washers and
    put them under the heads of all your nuts and bolts and corrosion problems
    should be minimized as much as possible.

    Marin's going to have apoplexy about my saying stainless fasteners are fine
    on a rover. All I can say is the Westsail 32 that we built is going strong
    after living in tropcal oceans all its life and sailing halfway round the
    world. When I put any fasteners or dissimilar metal on the mast or other
    aluminum pieces, I used either lock tight or aluminum never seize compound.
    The subsequent owners have done the same. Fasteners that have been in place
    since the beginning, are easily removed with an impact driver with virtually
    no sign of corrosion. Most of these fasteners are threaded directly into
    the aluminum, by the way. Aluminum used on boats is undoubtedly more
    corrosion resistant than aircraft aluminum but this boat has been constantly
    subjected to the most hostile of environments. High heat, high salt, and
    years at a stretch without fresh water wash downs. Using dissimilar metals
    below the water line is an entirely different story. You can get away with
    Monel, stainless and/or bronze, but aluminum never, on a fiberglass boat.
    If your hull is aluminum or steel, stainless is the only dissimilar metal
    that should be used below the water line and then only where it can't be
    avoided like the propellor shaft.

    So, use never seize or LocTight at every opportunity, put insulating
    materials under washers and bolt heads, and use galvanized fasteners, if
    possible. Take the above precautions in every other location but the rust
    belt, and stainless should be fine.

    Aloha
    Peter Ogilvie
    Kona Coffee Rover
    1970 88 soft top, 'huli' Mine since '84 but recovering
         from exposure of the dark side.
    1966 109 pickup 'slime' In my garage since '90, finally running.
    1965 88 parts car, slowly sinking into the lava.
    196? 88 hard top, possibly 'phoenix' if it rises, it will
         certainly be from ashes or at least a pile of rust

    >From: "C. Marin Faure" <faurecm@halcyon.com>
    >Reply-To: lro@works.team.net
    >To: lro-digest@Works.Team.Net
    >CC: SHARDING@SCHULTE-LAW.COM
    >Subject: LRO: Re: corrosion issues/shipfitters disease/sil
    >Date: Tue, 15 May 2001 01:47:37 -0700
    >
    >Date: Mon, 30 Apr 2001 10:51:00 -0700
    >From: SJH <SHARDING@SCHULTE-LAW.COM>
    >Subject: LRO: corrosion issues/shipfitters disease/sil
    >
    > >I recently pulled and refurbished the intermediate floor in my 109SW and
    >found some semi-serious corrosion at the extreme outboard ends of the
    >rearmost support flange for this floor panel. The floor panel is held in
    >place by large screws which screw into steel clips attached to the
    >support flange. The area around the hole where the clip is located on
    >the flange is heavily corroded/nonexistent.
    >
    >Have been on vacation, so only read your post today. You may have already
    >come up with solutions but:
    >
    >You could try welding or screwing in patches to cover the missing or weak
    >parts of the support flange, which you could then redrill for the steel
    >clips.
    >
    > >I want to stay away from steel fasteners
    >in this location which I guess is susceptible to corrosion because of
    >mud/moisture from the rear wheel, or the lack of grease/oil thrown in the
    >area (no similar extent corrosion on the front intermediate floor support
    >flange).
    >
    >I wouldn't worry too much about using steel fasteners. I've owned my SIII
    >for twenty-eight years, and I've not had any serious rust problems with the
    >fasteners the factory used, despite their being the cheapest grade crap
    >that the company could buy at the time. It's STAINLESS steel fasteners I'd
    >advise you to stay away from. Coating the steel fasteners you put in with
    >LPS-3 (not -1 or -2) will help ward off rust, and there are other products
    >you can use for this purpose, too. I use LPS-3 once a year on the
    >fasteners and springs on our boat trailer, and it's been pretty much
    >rust-free for over 15 years despite regular dippings in salt water.
    >
    > >I'd also like to hear from folks on using plastic discs under
    >washers in contact with aluminum, as well as plastic between the tub and
    >the frame mounting tabs?
    >
    >Big waste of time unless you can figure out how to insulate the fastener
    >itself from the metal it's holding together. As I explained in another
    >post, any conductive connection between two pieces of dissimilar metals
    >carries the potential for electrolysis and its associated corrosion. So
    >you not only have to insulate the parts themselves from each other, but the
    >barrel, head, and threads of all the fasteners as well.
    >
    >The crummy steel used in Series Land Rovers, the cheap fasteners, the tinny
    >washers, and the aluminum alloy skin are not all that far apart on the
    >Galvanic chart. So the potential for electrolysis on the "stock"
    >components of a Series is not all that great. Where you could get into
    >trouble is if you start using stainless steel on the vehicle, particularly
    >for fasteners that are going to be in conductive contact with the aluminum
    >alloy skin. Your biggest problem will be rust, depending on how you use
    >your vehicle and the environment where you live. Priming and painting
    >installed fasteners and/or coating them with LPS-3 or some other adhesive
    >protectant is your best defense against rust. Makng sure there are drain
    >holes in the bottoms of door structures and so forth helps, too.
    >
    >As I recall, you live in Oregon. I don't believe they use salt on the
    >roads down there, and unless you drive a lot on the beaches, I don't think
    >a humid, salt-air environment is going to be a factor for you. So giving
    >the new steel fasteners you install in your floor a good painting and/or
    >coating of LPS-3, etc. should protect your repair for many, many years.
    >
    >And if you do what I do, and put off replacing a leaking front crank seal
    >for decades, the oil blown back under the vehicle at speed will prevent
    >rust from forming on ANYTHING, even if you live in a hot, humid, salty
    >environment out in the middle of the Pacific.
    >
    >
    >________________________
    >C. Marin Faure
    > (original owner)
    > 1973 Land Rover Series III-88
    > 1991 Range Rover Vogue SE
    > Seattle, WA
    >
    >

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