hpeer wrote in news:49be353d$0$19669
:

Actually most steel boats are insulated with foam above the water line.
This is the commercial variant of the foam not the minimially
expanding Great Stuff.

However you make a good point for the repairs and I would only do it as
an immediate expedient to stop a leak until I could address it properly.



Someone I know bought a used pickup truck that looked brand new.

It had a professionally-installed, sprayed-in plastic bedliner that was
really expensive in it.

The first time he got it in the shop, he helped himself to the bottom of it
while it was up on the rack at his fav garage.

Looking around for anything wrong, he was STUNNED to see the BOTTOM OF THE
BEDLINER in big holes of rust that used to be the truck's pickup bed!
Water had gotten between this bedliner sprayed on it and the steel, eating
away first the paint, then the hull....just like it would in a steel hulled
boat.

It looked great from the top, of course, as the plastic covered up the rust
holes and seems to support the load. Maybe Ford shoulda made the whole bed
out of plastic!

Larry wrote:
hpeer wrote in news:49be353d$0$19669
:

Actually most steel boats are insulated with foam above the water line.
This is the commercial variant of the foam not the minimially
expanding Great Stuff.

However you make a good point for the repairs and I would only do it as
an immediate expedient to stop a leak until I could address it properly.



Someone I know bought a used pickup truck that looked brand new.

It had a professionally-installed, sprayed-in plastic bedliner that was
really expensive in it.

The first time he got it in the shop, he helped himself to the bottom of it
while it was up on the rack at his fav garage.

Looking around for anything wrong, he was STUNNED to see the BOTTOM OF THE
BEDLINER in big holes of rust that used to be the truck's pickup bed!
Water had gotten between this bedliner sprayed on it and the steel, eating
away first the paint, then the hull....just like it would in a steel hulled
boat.

It looked great from the top, of course, as the plastic covered up the rust
holes and seems to support the load. Maybe Ford shoulda made the whole bed
out of plastic!


Yeah, I think the foam works better than the bed liner. The foam is a
urethane and so is much of the marine paint. The bed liner appears to
be a polyethelyne or something but I'm not sure.

In article ,
hpeer wrote:

Yeah, I think the foam works better than the bed liner. The foam is a
urethane and so is much of the marine paint.

Be careful - urethane may be acidic, and iron rusts in acids.
In a basic environment it is stable such as in cement/concrete.

HTH

Marc

--
remove bye and from mercial to get valid e-mail
http://www.heusser.com

Marc Heusser wrote:
In article ,
hpeer wrote:

Yeah, I think the foam works better than the bed liner. The foam is a
urethane and so is much of the marine paint.

Be careful - urethane may be acidic, and iron rusts in acids.
In a basic environment it is stable such as in cement/concrete.

Say what? Best rethink that thought:
http://depts.washington.edu/matseed/...0Corrosion.htm


Cheers
Martin

Marty wrote:
Marc Heusser wrote:
In article , hpeer
wrote:

Yeah, I think the foam works better than the bed liner. The foam
is a urethane and so is much of the marine paint.

Be careful - urethane may be acidic, and iron rusts in acids. In a
basic environment it is stable such as in cement/concrete.

Say what? Best rethink that thought:
http://depts.washington.edu/matseed/...0Corrosion.htm

Sorry but that link actually supports the original argument.
From the link:

When considering the initial state of the reinforcement in our
concrete bridges, we can state that the cement acts to protect the
reinforcement by passivating it. It forms a protective oxide coating
on the steel giving a pH of 13-14 adjacent to the steel. The
corrosion of the steel reinforcement occurs below pH 11. The pH of
seawater is about 8.


Yep, confirmed, stable in a sufficiently basic environment.
Of course, if you have voids or cracks next to the steel, eventually
chloride ions will get in there, the PH will drop, the reinforcement
rust and the structure will fail, but that's not a problem with steel in
a basic environment, its a problem maintaining a basic environment.

For a counter-example, examine *any* unprotected steel object exposed to
acid fumes or acid contact. Even the top of an old ketchup bottle . . .


--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:

IanM wrote:



Yep, confirmed, stable in a sufficiently basic environment.
Of course, if you have voids or cracks next to the steel, eventually
chloride ions will get in there, the PH will drop, the reinforcement
rust and the structure will fail, but that's not a problem with steel in
a basic environment, its a problem maintaining a basic environment.

The devil is in the details.

We've a number of bridge problems, partial collapses, near failures on
many of the bridges and overpasses on the 401, (freeway connecting
Windsor to Montreal), seems the road salt was getting through the
concrete to the rebar. For ten years or so there has been an ongoing
project to replace the old bar, with new "green" rebar.

Cheers
Martin

On Mon, 16 Mar 2009 17:34:53 +0000, Larry wrote:

hpeer wrote in news:49be353d$0$19669
:

Actually most steel boats are insulated with foam above the water line.
This is the commercial variant of the foam not the minimially
expanding Great Stuff.

However you make a good point for the repairs and I would only do it as
an immediate expedient to stop a leak until I could address it properly.



Someone I know bought a used pickup truck that looked brand new.

It had a professionally-installed, sprayed-in plastic bedliner that was
really expensive in it.

The first time he got it in the shop, he helped himself to the bottom of it
while it was up on the rack at his fav garage.

Looking around for anything wrong, he was STUNNED to see the BOTTOM OF THE
BEDLINER in big holes of rust that used to be the truck's pickup bed!
Water had gotten between this bedliner sprayed on it and the steel, eating
away first the paint, then the hull....just like it would in a steel hulled
boat.

It looked great from the top, of course, as the plastic covered up the rust
holes and seems to support the load. Maybe Ford shoulda made the whole bed
out of plastic!


In Thailand you can buy all stainless beds for the more common models
of pickup trucks. You frequently see them on trucks used in the
fishing or other food industry business. My B-in-L who owns a fairly
large noodle factory uses them on all of his company pickups. He tells
me that it you buy a new pickup and drive directly to the "body shop"
for replacement you can get the stainless body for less then US$ 1000.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)