response 1 of 29:

Mar 18 01:20 UTC 1998

We have Grainger catalog, USG Gypsum Construction Handbook, Wiremold Buyer's
Guide, the 1981 National Electrical Code (got rid of 1979,I think 1981 was
still valid when we started building), Use Wrenches the Safe Way (US Dept of
Labor 1951), a 25C pocket book How to Work With Tools and Wood (1955),
a forties book on refrigeration (to match our refrigerator collection),
Household Encyclopedia (1966, including ideas for novelty wrappings, make your
own kitchen gadgets, furniture styles, washing dishes, The Lawn, How to Use
a Roller, 70 pages of home repair, 30 on painting, basic mending stitches,
How to Buy More for Your Money, Edible Weeds, Party Games for Adults, Typical
Family Budget, Dates on Which Ash Wednesday and Easter Sunday Fall, and
Language of Flowers, among many other topics.  First ed was 1953).  Complete
Book of Home Repair and Improvements, For Don from Aunt Helen, March 1952.
By the editors of Popular Mechanics.    Novel Igloo Incinerator of Troweled
Concrete Combines Both Utility and Atractiveness (drawing of son in shorts
and wife in dress feeding it bags of garbage).  

response 3 of 29:

Mar 18 20:11 UTC 1998

Who is the author?  Maybe the library will order it, if in print.
'Cement is troweled over metal lath to a 4-in thicness. THe wooden forms may
be burned away later.'  No special type of concrete is mentioned, sorry.
The Fine Homebuilding videos are stocked by the library, along with the books,
and we learned a lot about tiling.

response 5 of 29:

Mar 19 11:20 UTC 1998

I don't recall who the author is and the book is on seemingly indefinite
loan to some friends who can't be without it for even a week.  It is
already stocked by the library.
 
Gee, if we made concrete the old-fashioned way, there would be little
need for sewage treatment plants ;-)

response 7 of 29:

Mar 20 06:12 UTC 1998

Re polarity tester. That is only for DC, of course, and surely works only
above some minimum voltage. Do you know what it is? (I am pretty skeptical
of the proposal, and would have to see it to believe it - the rods really
are *touching* the solution, and the spark appears *in the liquid*?) What
if you don't have copper rods? When is this useful? All batteries are
marked or one can tell by shape. But just as a challenge...touch the
two wires to your tongue - the one that tastes sour is negative (the
other will taste bitter). Say..how did you do this, anyway? You said you
don't have salt. There must be a simpler way than any of the above..may
I use a compass?

response 9 of 29:

Mar 20 21:03 UTC 1998

I never said we built this gadget, Jim found it in a book and thought you
would enjoy disbelieving it.  We don't have ammonia either.  But we do have
several meters that do the job faster.  How long do you have to wait for the
copper to turn blue?  Jim wonders whether you would get hydrogen and oxygen
forming at the different electrodes, and the hydrogen would burn?
We have vinegar and baking soda and citric acid, washing soda, lye, epsom
salts (the last two left over from making soap and tofu, baking soda as a
deodorant, washing soda as a water softener, citric acid for canning and for
dissolving calcium out of eggshells to add to oatmeal as calcium citrate,
vinegar for washing our stucco walls to get off the inflorescence and for
removing stray mortar from bricks instead of HCl).  ANy other good uses for
our chemical arsenal?  Also we have tartaric acid which I boiled with
tarnished silver and a piece of aluminum foil.  And lime which we used to boil
with dried corn to get off the husk and convert the niacin, to make tortillas.

response 11 of 29:

Mar 20 21:53 UTC 1998

I could tell blue had developed on the paper in a few seconds with a 9-volt
battery and a copper wire spacing of ca. 1/2 inch. The rate of formation
depends on the current, which increases with voltage and decreases with
distance. This works by copper dissolving at the (+) electrode and reacting
with the ammonia to make an intense blue complex. Hydrogen is formed at
the (-) electrode, but not enough to be flammable in the time it takes to
do the experiment (give it an hour, though, and you might be able to
accumulate enough hydrogen to burn).

I look for what will solve a problem, and not what one might do with one's
chemical inventory. 

Don't use that aluminum trick on your silver if you value it. It etches
the silver and will, with repeated use, turn it matte.

response 13 of 29:

Mar 21 06:33 UTC 1998

Well, I thought it would be interesting to find a method that did not
involve a meter or reading the labels. I like puzzles, which are always
posed with constraints on information. You seemed to like the spark
method, since you cited it, so I undertook to devise a method that
would be more likely to work with less difficulty. I succeeded, and
demonstrated it. 

The aluminum acts as an anode to cathodically reduce the silver oxide and
silver sulfide tarnishes back to silver. This does two things: it makes
pits where the tarnish crystals were, and raises roughness where it grows
new silver crystals nearby. This process does not remove silver but rather
moves it around to create a less shiny surface. Only an abrasive, which
does remove silver, will polish it. 

response 15 of 29:

Mar 23 05:58 UTC 1998

Polishing does move some of the silver around but primarily abrades off
the irregularities. You do *not* want to use the aluminum method on
silver plate, since it is pitting the silver. 

The blue color formed is the cupric-ammonium ion Cu(NH3)4(2+). It is
a deep intense blue, and thus can be seen at very low concentrations.

I don't have polarity. It would be shocking if I did. I get my charge
other ways.

response 17 of 29:

Mar 24 06:54 UTC 1998

Well, once around with aluminum will improve the appearance for a while.
You could store it in anti-tarnish cloth, which helps a little (it absorbs
H2S). But silver polish would really accomplish the same. I do not know
for sure which method will go through the plate faster. You could polish
half of it, and "aluminum" the rest - and report back when you get through
the plate on either.

response 19 of 29:

Mar 25 06:56 UTC 1998

I agree that the test would have to be done on a large scale with many
participants, to average out the differences in spoons and uses.

NIckel silver is an alloy of nickel, copper and zinc. Tableware is
made from it. Hardened brass is also used. There is no toxicity problem
with metallic nickel alloys - they do not corrode readily.

response 21 of 29:

Mar 26 02:19 UTC 1998

We have some silverplate which show signs of rust where the plating has been
nicked etc.

response 23 of 29:

Mar 26 20:24 UTC 1998

Looked like copper blue to me, not blue-white.  Maybe my spoon was especially
high in copper content.  What is written on the back of the silverplate which
shows rust?