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| Author |
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popcorn
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Thermoses (thermii? :)
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Jun 9 15:57 UTC 1996 |
This item has been erased.
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| 31 responses total. |
scott
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response 1 of 31:
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Jun 9 16:07 UTC 1996 |
Hmm, I haven't really used one for years. I suppose the more you spend,
usually the higher the quality.
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kentn
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response 2 of 31:
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Jun 10 01:38 UTC 1996 |
I think the next time I buy a Thermos-like container, it'll probably be
one of those steel ones, if only for their durability. I've had too many
of the glass ones end up as a pile of shards after being bounced around.
Are the steel ones really more efficient than glass, though?
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rcurl
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response 3 of 31:
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Jun 10 04:27 UTC 1996 |
I use a steel Thermos. Its pretty good. One warning about it though - don't
clean out deposits from coffee or tea with chlorine bleach. I did, and it
wasn't long before the steel punctured. I now use perborate bleach - which
takes much longer, but isn't going to corrode the steel.
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omni
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response 4 of 31:
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Jun 11 03:11 UTC 1996 |
how strong was the bleach?
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rcurl
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response 5 of 31:
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Jun 11 06:31 UTC 1996 |
Oh, just a dollop in the thermos full of water. The problem is that
stainless steel is no good with chlorine - decidedly not "stainless"
(it dissolves). I didn't think it would be serious corrosion, but it
was.
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omni
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response 6 of 31:
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Jun 13 06:09 UTC 1996 |
Maybe you should have made a 100:1 solution of bleach and water (100 parts
of water), and that would reduce the corrosive effect.
Will tin rust?
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rcurl
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response 7 of 31:
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Jun 13 21:13 UTC 1996 |
"Tin" means both the element Sn, a metal moderately resistant to corrosion,
or as a general term for steel sheet plated with tin. Only iron "rusts"
(rust=iron oxide), but tin does react slowly in strong acids or alkalis.
Tin does not protect iron like zinc does - galvanically - so iron exposed
by a pinhole in tin plate will rust as quickly as unplated iron.
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freida
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response 8 of 31:
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Jun 14 00:07 UTC 1996 |
Is this why tin roofs rust eventually?
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rcurl
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response 9 of 31:
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Jun 14 07:03 UTC 1996 |
"Tin" roofs are likely not to be tin-plated, but rather galvanized. The
term "tin" is used loosely for any thin steel sheet. I just looked up
metal roofing in a building materials catalog, and it is 29 gauge
galvanized (zinc-coated) steel - no tin. It should have been "Cat on
a Hot Galvanized Roof". Galvanized steel roofs will last a lot longer
than a tin-plated steel roof, because exposed steel of a galvanized roof
does not rust until most of the zinc is gone, while it would start to
rust immediately with the smallest pinhole, if tinned.
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freida
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response 10 of 31:
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Jun 15 03:57 UTC 1996 |
AAAAH! Thanks Rane! I was wondering why the "tin"roofs on all the old barns
and stuff was only just begining to rust after around 30 years....that zinc
must be hard stuff to wear off so slowly!
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srw
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response 11 of 31:
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Jun 15 04:46 UTC 1996 |
It's not the strength of the zinc itself, but the way it bonds to the iron.
It is chemistry rather than materials science.
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rcurl
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response 12 of 31:
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Jun 17 06:36 UTC 1996 |
Materials science is chemistry...but we'll let that go. Zinc corrodes
slowly but also becomes coated with a protective layer of the basic
carbonate. More important, it does not engage in an electrical process of
self-destruction that involves products of rusting of iron. Then, as long
as there is zinc near iron, even after the zinc gets holes in it, another
electrical process causes the zinc to be sacrificed rather than the iron
(a process called "cathodic protection" - it is used on ships too, to
protect parts like the propeller shaft, by clamping on a "sacrificial"
disk of zinc).
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freida
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response 13 of 31:
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Jun 18 20:20 UTC 1996 |
AAAhhhh! so a tin roof might not be such a bad idea for a house...
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rcurl
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response 14 of 31:
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Jun 19 06:35 UTC 1996 |
I've often seen galvanized steel roofing on houses in rural areas. Perhaps
they are used more there because they are common for farm buildings.
_Architectural Graphic Standards_ says they should be *painted* every
3 or 4 years. (AGS refers to metal roofing in general as "Tin Roofing",
but has additional sections on copper, zinc, galvanized iron, lead,
and canvas (!) roofing.) Industrial buildings usually use corrugated
galvanized steel roofing with no underlay but the homes I've seen use
what is called "standing seam roofing", which is laid over sheathing.
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n8nxf
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response 15 of 31:
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Jun 19 12:03 UTC 1996 |
I'd like to put a metal roof on the house I'm planing to build. The
other day I was blown away when I came across a house with a stainless
steel roof while riding back from Cycle Cellar on Felch St. It was
of the standing seem variety and, beaing a part time machinist, I'm
pretty sure it was not aluminum. (This house has been under construction
for several years and seems to be a DIY project. It is quite unique
and turning out quite nice!)
I have run across "corrugated" galvanized roofing being used in energy
efficend designs in Sweden.
BTW, what are the byproducts of a stainless / chlorine reaction?
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rcurl
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response 16 of 31:
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Jun 19 20:09 UTC 1996 |
Chlorides....(iron, chromium, nickel...). However in alkaline medium these
precipitate again as hydroxides and oxides, but get washed away. Titanium
would be OK. I don't think you will find any *rural* SS roofs (except in
a high rent district).
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freida
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response 17 of 31:
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Jun 20 00:30 UTC 1996 |
Boy do you have that correct, Rane. I recently checked into different roofing
materials at the 84 lumber yard. They have "tin" roofing which is painted
and has a 30 year warranty on the paint. Guess it is somehow bonded to the
metal. They looked pretty cool and I have seen some on houses around the
area. Guess I will have to do some thorough checking before any decisions
are made, but seemed like the metal roofing was almost as expensive as the
tile stuff. What is that raised seam thing Rane? Sorry to be so stupid on
the subject...only just starting to investigate it.
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mcpoz
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response 18 of 31:
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Jun 20 01:45 UTC 1996 |
If you ever drive through Baraboo, Wisconsin, about 2/3 of all the houses have
standing seam metal roofs. Seems there was a very successful tinsmith years
back.
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rcurl
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response 19 of 31:
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Jun 20 06:22 UTC 1996 |
The separate "tin" sheets have bent-up flanges along their sides. On some
varieties, the flang is bent up and then over and down, and the flange
of the next sheet fits under that. On others, apparently, the overlap is
small, and that is bent over in place to seal the seam (it is easier to
draw pictures of this than describe it). Standing seam roofing requires
a roof pitch of 1/4 or greater. I'm not sure of all the issues involved
in choosing one roofing over another, besides cost. I think I recall that
the steep-pitch, standing-seam tin roofing is useful in areas of heavy
snow, as the snow slides off most readily.
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scott
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response 20 of 31:
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Jun 20 11:13 UTC 1996 |
I suspect that tall seams helps by getting the leaky (or potentially leaky)
part up off where the water is going to sit.
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n8nxf
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response 21 of 31:
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Jun 20 11:47 UTC 1996 |
A bit further north of here in MI you'll see houses where the lower
portion of the roof is covered with sheet metal. I suspect because of
problems with ice dams. Shingled roofs are popular here butI'd like
to try something different. I don't like the idea of tossing 2 or 3
cubic yards of old shingles into the landfill every 15 or so years not
to mention another $3 to 5 grand to pay for it all.
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scott
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response 22 of 31:
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Jun 20 16:39 UTC 1996 |
In my neighborhood there are some houses with metal roofs that have seams.
the seams are about 2 feet apart and stick out about 3-4 inches. The seams
run verically, as you might have guessed.
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gracel
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response 23 of 31:
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Jun 20 18:23 UTC 1996 |
The house we used to own in Ann Arbor (1110 Miner) had a metal roof,
to go with the rest of its metal exterior ... when someone was getting
estimates for having it painted, we had to remind them that the roof
also needed painting.
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freida
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response 24 of 31:
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Jun 20 18:37 UTC 1996 |
Aaahhh yes! I recently purchased two sheets of galvanized, corogated (sp)
metal to put over the top of the cister. From this experience, I can see what
you are talking about with the raised seams. The seam area must just be a
bit higher than on these peices, but the fit of one under the other was
excellant. (oops I mean pieces)...Boy, I can't spell today! change to great!
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