Ally corrosion ??

My 110 has a lump of aluminium ( alloy ? ) holding the front screen to the
body. It seems to be the only part badly affected by the white powder. Is
there any way of preparing it and then resealing it against further
corrosion ?

I know this is an age old question but I cannot understand why it is so bad
( I do undersatnd the chemistry involved being a Chemistry graduate but the
simplicity of it beats me )

--


" ..... it is the provenence of knowledge to speak, and it is the privelage
of wisdom to listen"

In message <[email protected]>
"Hirsty's" <[email protected]> wrote:

>My 110 has a lump of aluminium ( alloy ? ) holding the front screen to
>the body. It seems to be the only part badly affected by the white
>powder. Is there any way of preparing it and then resealing it against
>further corrosion ?
>
>I know this is an age old question but I cannot understand why it is
>so bad ( I do undersatnd the chemistry involved being a Chemistry
>graduate but the simplicity of it beats me )
>

What little knowledge of aluminium corrosion I know is posted below.

Aluminium which is an oily metal requires "etch priming" to provide a
suitable key to promote paint adhesion. Acid etch is a corrosion
preventive phosphoric acid that can be applied by spray or roller it is
not a substance that can be successfully applied by brush mainly
because it is a rapid drying alcohol base formulated to spread thinly
and therefore very evenly over the surface.

Aluminium (or the Birmabright used on series Land Rovers) is classed as
a reactive metal and like iron it reacts with oxygen causing surface
corrosion. Aluminium left in its bare metal state corrodes producing
"aluminium oxide" which is a form of corrosion that will completely
cover the surface and yet to some degree actually protects it from
further corrosion. This white "aluminium oxide powder" formed on bare
aluminium is naturally weak having little or no strength and can
easily be scraped off leading to further corrosion.
The oxide forming process is called anodising.

Anodising aluminium by an electro chemical process physically alters
the metal surface and produces a really tough dense layer of oxide
offering maximum protection to bare aluminium.
Because the chemical structure is different on aluminium as opposed to
steel the anodising process can be used as an anti-corrosion advantage
leaving the finished aluminium absolutely bare with no need for paint
protection.
Although a similar process exists for steel the surface corrosion must
be protected by paint.

To put it simply in your case its the paint that has failed allowing
the aluminium to become unprotected and oxidise which now requires
re-etching and re-painting.

The preparation is easy enough to do and you might find this:
"http://www.stephen.hull.btinternet.co.uk/prep.html" helpful as
it shows a basic method at least of preparing aluminium prior to paint.

Steve.


--
Vehicle Painting Pointers: http://www.stephen.hull.btinternet.co.uk
Coach painting tips and techniques + Land Rover colour codes
Using a British RISC Operating System 100% immune to any Windows virus.
"Whatever is rightly done, however humble, is noble". Henry Royce

Hirsty's wrote:
> My 110 has a lump of aluminium ( alloy ? ) holding the front screen
> to the body. It seems to be the only part badly affected by the white
> powder. Is there any way of preparing it and then resealing it
> against further corrosion ?
>
> I know this is an age old question but I cannot understand why it is
> so bad ( I do undersatnd the chemistry involved being a Chemistry
> graduate but the simplicity of it beats me )

Mines exactly the same, it beats Land Rover too, you have to keep the two metals apart (bulkhead is
steel) to prevent this type of thing. The screen surround is seperated from the bulkhead by a rubber
screen seal but the hinges (also alloy) fit direct to the bulkhead & the screen surround. The way it
looks on mine is the corrosion has crept up the hinges bypassing the sealing strip. This is hat causes it
I believe.

What can be done about it is another matter I have not yet looked into!!

Nige


--
Subaru WRX (Annabel)

Landrover 110 County Station Wagon (Tyson)

'"Say hello to my little friend"

"Nige" <[email protected]> wrote in message
news:[email protected]...
> Hirsty's wrote:
>> My 110 has a lump of aluminium ( alloy ? ) holding the front screen
>> to the body. It seems to be the only part badly affected by the white
>> powder. Is there any way of preparing it and then resealing it
>> against further corrosion ?
>>
>> snip

While etch priming is the most important part of securing the paint to the
outside, there is another problem. The steel studs that secure the aluminium
blocks (used to be hinges) are screwed straight in the back. There is also
the possibility that tightening the inside nuts has damaged the paint on the
bulkhead and there is now a direct path between aluminium and steel and
electrolytic corrosion is happening. There are some exotic assembly pastes
that minimise this sort of thing. "Titanine" is the name of one that springs
to mind. It was used mainly on things like aeroplanes, so I'm not sure where
you might buy it for domestic use. I have used a Shell product called
"Ensis" with some success. This is the brown stuff that comes smeared all
over new bearings etc. to stop them corroding. It comes in a spray can, as
liquid or even a grease (for electric motor sealing I think). The corner
garage probably will not have it but a specialist outlet should be able to
order it.

Regards,

Nick Webster

NW wrote:

>
> "Nige" <[email protected]> wrote in message
> news:[email protected]...
>> Hirsty's wrote:
>>> My 110 has a lump of aluminium ( alloy ? ) holding the front screen
>>> to the body. It seems to be the only part badly affected by the white
>>> powder. Is there any way of preparing it and then resealing it
>>> against further corrosion ?
>>>
>>> snip
>
> While etch priming is the most important part of securing the paint to the
> outside, there is another problem. The steel studs that secure the
> aluminium blocks (used to be hinges) are screwed straight in the back.
> There is also the possibility that tightening the inside nuts has damaged
> the paint on the bulkhead and there is now a direct path between aluminium
> and steel and electrolytic corrosion is happening. There are some exotic
> assembly pastes that minimise this sort of thing. "Titanine" is the name
> of one that springs to mind. It was used mainly on things like aeroplanes,
> so I'm not sure where
> you might buy it for domestic use. I have used a Shell product called
> "Ensis" with some success. This is the brown stuff that comes smeared all
> over new bearings etc. to stop them corroding. It comes in a spray can, as
> liquid or even a grease (for electric motor sealing I think). The corner
> garage probably will not have it but a specialist outlet should be able to
> order it.

Isn't it enough to electrically insulate steel from aluminium? In which
case some kind of plastic/rubber spacer should do the trick. Inner tube
springs to mind in that case. Or even tape?

Fred

In message <[email protected]>
Fred Labrosse <[email protected]> wrote:

> NW wrote:
>
> >
> > "Nige" <[email protected]> wrote in message
> > news:[email protected]...
> >> Hirsty's wrote:
> >>> My 110 has a lump of aluminium ( alloy ? ) holding the front screen
> >>> to the body. It seems to be the only part badly affected by the white
> >>> powder. Is there any way of preparing it and then resealing it
> >>> against further corrosion ?
> >>>
> >>> snip
> >
> > While etch priming is the most important part of securing the paint to the
> > outside, there is another problem. The steel studs that secure the
> > aluminium blocks (used to be hinges) are screwed straight in the back.
> > There is also the possibility that tightening the inside nuts has damaged
> > the paint on the bulkhead and there is now a direct path between aluminium
> > and steel and electrolytic corrosion is happening. There are some exotic
> > assembly pastes that minimise this sort of thing. "Titanine" is the name
> > of one that springs to mind. It was used mainly on things like aeroplanes,
> > so I'm not sure where
> > you might buy it for domestic use. I have used a Shell product called
> > "Ensis" with some success. This is the brown stuff that comes smeared all
> > over new bearings etc. to stop them corroding. It comes in a spray can, as
> > liquid or even a grease (for electric motor sealing I think). The corner
> > garage probably will not have it but a specialist outlet should be able to
> > order it.
>
> Isn't it enough to electrically insulate steel from aluminium? In which
> case some kind of plastic/rubber spacer should do the trick. Inner tube
> springs to mind in that case. Or even tape?
>

True. In the case of the Defender front screen the hinges (dummy or
real) should have gaskets to keep things apart.

> Fred
>

Richard

--
www.beamends-lrspares.co.uk [email protected]
Running a business in a Microsoft free environment - it can be done
Powered by Risc-OS - you won't get a virus from us!!
Boycott the Yorkshire Dales - No Play, No Pay

"beamendsltd" <[email protected]> wrote in message
news:239353ae4d%[email protected]...
> In message <[email protected]>
> Fred Labrosse <[email protected]> wrote:
>
>> NW wrote:
>>
>> >
>> > "Nige" <[email protected]> wrote in message
>> > news:[email protected]...
>> >> Hirsty's wrote:
>> >>> My 110 has a lump of aluminium ( alloy ? ) holding the front screen
>> >>> to the body. It seems to be the only part badly affected by the white
>> >>> powder. Is there any way of preparing it and then resealing it
>> >>> against further corrosion ?
>> >>>
>> >>> snip
>> >
>> > While etch priming is the most important part of securing the paint to
>> > the
>> > outside, there is another problem. The steel studs that secure the
>> > aluminium blocks (used to be hinges) are screwed straight in the back.
>> > There is also the possibility that tightening the inside nuts has
>> > damaged
>> > the paint on the bulkhead and there is now a direct path between
>> > aluminium
>> > and steel and electrolytic corrosion is happening. There are some
>> > exotic
>> > assembly pastes that minimise this sort of thing. "Titanine" is the
>> > name
>> > of one that springs to mind. It was used mainly on things like
>> > aeroplanes,
>> > so I'm not sure where
>> > you might buy it for domestic use. I have used a Shell product called
>> > "Ensis" with some success. This is the brown stuff that comes smeared
>> > all
>> > over new bearings etc. to stop them corroding. It comes in a spray can,
>> > as
>> > liquid or even a grease (for electric motor sealing I think). The
>> > corner
>> > garage probably will not have it but a specialist outlet should be able
>> > to
>> > order it.
>>
>> Isn't it enough to electrically insulate steel from aluminium? In which
>> case some kind of plastic/rubber spacer should do the trick. Inner tube
>> springs to mind in that case. Or even tape?
>>
>
> True. In the case of the Defender front screen the hinges (dummy or
> real) should have gaskets to keep things apart.
>
>> Fred
>>
>
> Richard
>
> --
> www.beamends-lrspares.co.uk [email protected]
> Running a business in a Microsoft free environment - it can be done
> Powered by Risc-OS - you won't get a virus from us!!
> Boycott the Yorkshire Dales - No Play, No Pay
>
>
Yes, indeed, but my point was that not only do you have to insulate the
block but also the studs that fasten it on - that literally short circuits
the hinge insulation through the bulkhead.

I was also miserably looking at another well known trouble area on my Landy
today. The rear body corners (the bit where the rear lights fasten). They
are painted steel and look fine but the paint is lifting off the aluminium
either side of them. It has never been the same since L-R stopped
galvanising them. In order to do a good remedial job, I figure the corner
plate ought to be taken off. They look like they tuck under the capping
around the top of the body tub. If I drill out the rivets, does anyone know
whether the corner will pull away easily?

Nick

In message <[email protected]>
"NW" <[email protected]> wrote:

>
> "beamendsltd" <[email protected]> wrote in message
> news:239353ae4d%[email protected]...
> > In message <[email protected]>
> > Fred Labrosse <[email protected]> wrote:
> >
> >> NW wrote:
> >>
> >> >
> >> > "Nige" <[email protected]> wrote in message
> >> > news:[email protected]...
> >> >> Hirsty's wrote:
> >> >>> My 110 has a lump of aluminium ( alloy ? ) holding the front screen
> >> >>> to the body. It seems to be the only part badly affected by the white
> >> >>> powder. Is there any way of preparing it and then resealing it
> >> >>> against further corrosion ?
> >> >>>
> >> >>> snip
> >> >
> >> > While etch priming is the most important part of securing the paint to
> >> > the
> >> > outside, there is another problem. The steel studs that secure the
> >> > aluminium blocks (used to be hinges) are screwed straight in the back.
> >> > There is also the possibility that tightening the inside nuts has
> >> > damaged
> >> > the paint on the bulkhead and there is now a direct path between
> >> > aluminium
> >> > and steel and electrolytic corrosion is happening. There are some
> >> > exotic
> >> > assembly pastes that minimise this sort of thing. "Titanine" is the
> >> > name
> >> > of one that springs to mind. It was used mainly on things like
> >> > aeroplanes,
> >> > so I'm not sure where
> >> > you might buy it for domestic use. I have used a Shell product called
> >> > "Ensis" with some success. This is the brown stuff that comes smeared
> >> > all
> >> > over new bearings etc. to stop them corroding. It comes in a spray can,
> >> > as
> >> > liquid or even a grease (for electric motor sealing I think). The
> >> > corner
> >> > garage probably will not have it but a specialist outlet should be able
> >> > to
> >> > order it.
> >>
> >> Isn't it enough to electrically insulate steel from aluminium? In which
> >> case some kind of plastic/rubber spacer should do the trick. Inner tube
> >> springs to mind in that case. Or even tape?
> >>
> >
> > True. In the case of the Defender front screen the hinges (dummy or
> > real) should have gaskets to keep things apart.
> >
> >> Fred
> >>
> >
> > Richard
> >
> > --
> > www.beamends-lrspares.co.uk [email protected]
> > Running a business in a Microsoft free environment - it can be done
> > Powered by Risc-OS - you won't get a virus from us!!
> > Boycott the Yorkshire Dales - No Play, No Pay
> >
> >
> Yes, indeed, but my point was that not only do you have to insulate the
> block but also the studs that fasten it on - that literally short circuits
> the hinge insulation through the bulkhead.
>
> I was also miserably looking at another well known trouble area on my Landy
> today. The rear body corners (the bit where the rear lights fasten). They
> are painted steel and look fine but the paint is lifting off the aluminium
> either side of them. It has never been the same since L-R stopped
> galvanising them. In order to do a good remedial job, I figure the corner
> plate ought to be taken off. They look like they tuck under the capping
> around the top of the body tub. If I drill out the rivets, does anyone know
> whether the corner will pull away easily?
>

In theory - yes, there is no "top" to prevent it being pulled down, but
whether it would work in practice....

> Nick
>

Richard


--
www.beamends-lrspares.co.uk [email protected]
Running a business in a Microsoft free environment - it can be done
Powered by Risc-OS - you won't get a virus from us!!
Boycott the Yorkshire Dales - No Play, No Pay

"beamendsltd" <[email protected]> wrote in message
news:e680ceae4d%[email protected]...
> In message <[email protected]>
> "NW" <[email protected]> wrote:
>
>>
>> "beamendsltd" <[email protected]> wrote in message
>> news:239353ae4d%[email protected]...
>> > In message <[email protected]>
>> > Fred Labrosse <[email protected]> wrote:
>> >
>> >> NW wrote:
>> >>
>> >> >
>> >> > "Nige" <[email protected]> wrote in message
>> >> > news:[email protected]...
>> >> >> Hirsty's wrote:
>> >> >>> My 110 has a lump of aluminium ( alloy ? ) holding the front
>> >> >>> screen
>> >> >>> to the body. It seems to be the only part badly affected by the
>> >> >>> white
>> >> >>> powder. Is there any way of preparing it and then resealing it
>> >> >>> against further corrosion ?
>> >> >>>
>> >> >>> snip
>> >> >
>> >> > While etch priming is the most important part of securing the paint
>> >> > to
>> >> > the
>> >> > outside, there is another problem. The steel studs that secure the
>> >> > aluminium blocks (used to be hinges) are screwed straight in the
>> >> > back.
>> >> > There is also the possibility that tightening the inside nuts has
>> >> > damaged
>> >> > the paint on the bulkhead and there is now a direct path between
>> >> > aluminium
>> >> > and steel and electrolytic corrosion is happening. There are some
>> >> > exotic
>> >> > assembly pastes that minimise this sort of thing. "Titanine" is the
>> >> > name
>> >> > of one that springs to mind. It was used mainly on things like
>> >> > aeroplanes,
>> >> > so I'm not sure where
>> >> > you might buy it for domestic use. I have used a Shell product
>> >> > called
>> >> > "Ensis" with some success. This is the brown stuff that comes
>> >> > smeared
>> >> > all
>> >> > over new bearings etc. to stop them corroding. It comes in a spray
>> >> > can,
>> >> > as
>> >> > liquid or even a grease (for electric motor sealing I think). The
>> >> > corner
>> >> > garage probably will not have it but a specialist outlet should be
>> >> > able
>> >> > to
>> >> > order it.
>> >>
>> >> Isn't it enough to electrically insulate steel from aluminium? In
>> >> which
>> >> case some kind of plastic/rubber spacer should do the trick. Inner
>> >> tube
>> >> springs to mind in that case. Or even tape?
>> >>
>> >
>> > True. In the case of the Defender front screen the hinges (dummy or
>> > real) should have gaskets to keep things apart.
>> >
>> >> Fred
>> >>
>> >
>> > Richard
>> >
>> > --
>> > www.beamends-lrspares.co.uk [email protected]
>> > Running a business in a Microsoft free environment - it can be done
>> > Powered by Risc-OS - you won't get a virus from us!!
>> > Boycott the Yorkshire Dales - No Play, No Pay
>> >
>> >
>> Yes, indeed, but my point was that not only do you have to insulate the
>> block but also the studs that fasten it on - that literally short
>> circuits
>> the hinge insulation through the bulkhead.
>>
>> I was also miserably looking at another well known trouble area on my
>> Landy
>> today. The rear body corners (the bit where the rear lights fasten). They
>> are painted steel and look fine but the paint is lifting off the
>> aluminium
>> either side of them. It has never been the same since L-R stopped
>> galvanising them. In order to do a good remedial job, I figure the corner
>> plate ought to be taken off. They look like they tuck under the capping
>> around the top of the body tub. If I drill out the rivets, does anyone
>> know
>> whether the corner will pull away easily?
>>
>
> In theory - yes, there is no "top" to prevent it being pulled down, but
> whether it would work in practice....
>
>> Nick
>>
>
> Richard
>
>
> --
> www.beamends-lrspares.co.uk [email protected]
> Running a business in a Microsoft free environment - it can be done
> Powered by Risc-OS - you won't get a virus from us!!
> Boycott the Yorkshire Dales - No Play, No Pay

Having recently waved goodbye to my old 1988 Landy 110 csw with astonishing
corrosion around the cappings, this is an interesting thread, since I dread
the same thing happening again. After the briefest of studies on the net, I
think that the best thing for the new(ish) Defender is to take off all the
painted steel bits I can and hunt out galvanised replacements. The following
links make quite interesting reading.

http://www.iza.com/zwo_org/Applications/General_Galv/030802.htm

http://www.geometrica.com/Bulk_Storage/Material/SteelOrAlum.htm

Nick
Trying to make a TD5 last as long as a series 3.

NW wrote:

>
> Having recently waved goodbye to my old 1988 Landy 110 csw with
> astonishing corrosion around the cappings, this is an interesting thread,
> since I dread the same thing happening again. After the briefest of
> studies on the net, I think that the best thing for the new(ish) Defender
> is to take off all the painted steel bits I can and hunt out galvanised
> replacements.

I discovered a bit of rust around one of the rivets holding the right rear
angle steel bit. I applied waxoyl to it a few months ago, but clearly this
was not enough. I'm gonna remove the rivet, paint the steel (hammerite)
and then re-rivet with waxoyl everywhere in the hole. I'll see what that
does.

Fred

> Trying to make a TD5 last as long as a series 3.

Trying to achieve the same, which involves loads of hammerite, waxoyl and
time...