evan on thu 22 feb 01
However with an Ohaus triple beam you can weigh up to 2.6 kg with 0.1
gram precision. I think this is still the best price/performance
choice. Yes the electric ones are a bit more convenient. But the
triple beam is good for small tests and for mixing up full batches.
I also have an old direct reading pan balance that works by shining a
light past a graduated piece of film. As the pan moves down different
numbers are projected onto the front window. Weighs up to 10 kg with 1
g precision (you have to adjust a dial to read off the grams). Of
course that isn't quite enough for a full 10 kg batch because of the
tare.
So my dream electronic balance reads up to 12 or 15 kg with 1 g
precision but anything similar that I have found is quite expensive.
-- Evan in W Richland WA who saw about a dozen white pelicans flying in
the distance. Don't usually see that many at once.
Cindy Strnad wrote:
>
> A word about scales:
>
> I bought a digital scale, maybe last fall. Weighs up to 1000 grams, to
> within 1 gram accuracy. It is a Tanita model 1144, and I believe it set me
> back about $70. The only "flickering" I've observed is when I'm near the
> weight of the next gram up. This is handy, as it gives me an idea of when
> I'm "dead on" and when I might be at a half gram higher. Useful for things
> like chromium, though not needed generally.
Alisa og Claus Clausen on thu 22 feb 01
Dear Clayart,
=CFn reference to digital vs. beam scales, I much prefer my old beam =
scale to the new digital scale I have. Although the digital scales seem =
easy, you can stand back and just weigh away, they can have a tendency =
to flutter when one is weighing very small portions, for example under 5 =
grams. Beam scales settle and stay there.=20
I know there are super expensive digitals (lab models) out there that =
could change my opinion, but when I replace my scale, I am sure I will =
buy a beam.=20
Best regards,
Alisa
Cindy Strnad on thu 22 feb 01
A word about scales:
I bought a digital scale, maybe last fall. Weighs up to 1000 grams, to
within 1 gram accuracy. It is a Tanita model 1144, and I believe it set me
back about $70. The only "flickering" I've observed is when I'm near the
weight of the next gram up. This is handy, as it gives me an idea of when
I'm "dead on" and when I might be at a half gram higher. Useful for things
like chromium, though not needed generally.
Now, nothing beats the accuracy of a good quality beam scale, properly used.
But I think this digital scale matches it. I tested it out with all my
little weights and it was right on every time. It's quicker, relies less on
my patience, and cheaper. It tares out the weight of my measuring cup with
the touch of a button, flips from grams to ounces easily, and is quick to
clean. So, not all electronic scales are created equal, apparently. I know
I'm very pleased with mine.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
Charles Moore on sat 24 feb 01
Cindy Strnad,
You recently mentioned you satisfaction with an electronic scale called a
Tanita model 1144. Where did you find it? When I checked Tanita's web
site, I did not encounter that model; the site featured bathroom and fitness
scales. Tanita did provide a list of local shops (near my zip code), but
the shops are drug stores and fitness centers.
Thanks once again for your help.
Charles Moore
camoore33@earthlink.net
Cindy Strnad wrote:
I bought a digital scale, maybe last fall. Weighs up to 1000 grams, towithin
1 gram accuracy. It is a Tanita model 1144, and I believe it set me back
about $70. The only "flickering" I've observed is when I'm near the weight
of the next gram up. This is handy, as it gives me an idea of when I'm "dead
on" and when I might be at a half gram higher. Useful for things like
chromium, though not needed generally.
Ivor Townshend on sun 25 feb 01
I have read this thread with interest, and am concerned about the
kind of accuracy sought. In deciding this we should also consider
what we are going to do with the weighed material.
Will there be any losses in transferring the weighed material to the
batch?
Will the subsequent treatment (eg Sieving) remove some of the
weighed material selectively?
What is the effect of say a 1% error on the results?
Speaking for my own work, I would'nt expect any changes less
than 1% of each weighing to have much effect on results. and I
say this having first studied chemistry nearly 50 years ago!
For me, the real inference is that we should use the right balance
for the job.
If I'm weighing 5 kilo of feldspar, then the balance needs to weigh a
bit better than plus-or-minus 50gms.
However, if I'm weighing 50 gms of Cobalt Oxide then the balance
needs to weigh better than plus-or-minus half-a-gram.
A cheap electronic scale does the first quickly and easily. (and
hey - I like to watch the readout rise as I add the feldspar - it
makes weighing quick and easy).
To weigh the oxide I would nip into college and use the lab scale or
use my little Hamilton Scale (cheap and imported here from the
US). The Hamilton is less easy to use as it bobs up and down a
bit but it does its job.
Whilst a glaze containing Cobalt Oxide 1% is very different from
one containing 2%, the above approach would give a result
between 0.99% and 1.01%. In my experience these differences
are indistinguishable. I'm happy with this 1% accuracy.
We would say "horses for courses". Asking for 10kg plus-or-minus
1g is asking too much of one scale unless cost is not a problem.
Ivor
In Macclesfield UK
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