John Baymore on fri 9 jul 99
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A quick thought or two about the weighing out of materials problem.
I too use a tick sheet when weighing out materials to double check myself.
Insight prints out what is called a mix ticket.... a sheet with the weights
and a place for check marks. When weighing out stuff, things like the
phone ringing become secondary to the important project..... weighing
glaze. Let the studio answering machine take it. Always use the SAME
procedure..... either check the sheet after you pour it in or after you get
the weight right.... but always do it the same..... so you can probably
remember where you are in the process at any given time (....oops....did I
just dump that in or didn't I?).
The limited capacity of a triple beam balance is it's main drawback.....
and it what you trade for the typical tenth of a gram plus or minus
accuracy.
If you typically weigh out larger amounts of materials repeatedly and want
to reduce the risks of mis-calculating how many 500 gram scoops full you
have dumped in to the glaze bucket as you attempt to weight out 5438 grams
of feldspar.............
Invest in a large capacity digital gram scale. You can find them pretty
inexpensively these days. For less than =24150 you should be able to find
one that will weigh out more material than you are likely to want to in one
large single batch and also be reasonably accurate. Look for the
resolution (how accurate it is). Get the finest resolution you can
afford.....and keep that plus or minus figure in mind when you decide when
to use that particular scale.
If you are weighing out 5000 grams of feldspar and the accuracy of the
digital scale is plus or minus 5 grams....... you are not too far off on
the feldspar in a total glaze batch of 20,000 grams. ( 5 grams is what
percent of 20,000 =3Cg=3E). If however you use that scale to weigh out 1000
grams of feldspar for a 5000 gram total batch.....the error becomes pretty
significant. So in some cases it works OK and in others don't do it.
On large glaze batches you can use the large capacity digital to weigh out
the bulk amount ingredients and only use the triple beam for the
ingredients that are included in smaller amounts.
Well worth the investment if you make a lot of glaze. Your TIME is worth
money, and the decreased possibility of dumping errors goes down.
BEst,
......................................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752
JBaymore=40compuserve.com
John.Baymore=40GSD-CO.COM
=22Earth, Water, and Fire climbing kiln firing workshop Aug. 20-29,1999 -
one space available=22
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