Dave Finkelnburg on tue 15 jun 04
Mike,
Go to http://www.acers.org
Click on "Ceramic Resources,"
Then click on "Clayart,"
Then click on "Archives,"
Then click on "Search the archives,"
Then in the "For" line, type in what you are looking for, in this case
something like "weight dry ingredients glaze" and do a search from June of
1995 to June of 2004. You'll get about 15 hits, virtually all about
Brongniart's formula, which is what you want.
This was discussed most recently in January and February of this year.
I hope this is helpful.
Dave Finkelnburg in Idaho
----- Original Message -----
From: "Mike Martino"
Sent: Tuesday, June 15, 2004 2:05 PM
> I was discussing the possibility of calculating the weight of the dry
> ingredients of an already mixed glaze
Roger Graham on wed 16 jun 04
For Mike, who was asking about calculating the weight of dry ingredients in
an already-mixed glaze. The usual Brongniart's formula is a messy thing to
calculate, but if you're prepared to round off the figures a little, it
makes sense to do all this with a look-up table. You need some way to
measure the specific gravity of the glaze, that's all.
Here's the look-up table I use, made out on the assumption that the average
specific gravity of the dry glaze ingredients is about 2.6
SG of Glaze Dry Matter in 1 Litre (grams) Volume containing 100
grams of solid (mL)
1.05 * 81 *
1231
1.1 * 162 *
615
1.15 * 244 *
410
1.2 * 325 *
308
1.25 * 406 *
246
1.3 * 487 *
205
1.35 * 569 *
176
1.4 * 650 *
154
1.45 * 731 *
137
1.5 * 812 *
123
1.55 * 894 *
112
1.6 * 975 *
103
1.65 * 1056 *
95
1.7 * 1137 *
88
If the columns of figures don't line up on your screen display, email me off
list and I can send a pdf version which will print out in a neat table. And
if measuring the specific gravity of the glaze is a problem, ask also for a
print of the simple instruction sheet for making a plain-vanilla hydrometer.
Not moon rocket science at all, just fiddly arithmetic.
Roger Graham, near Gerringong, Australia
http://members.optusnet.com.au/~rogergraham
mailtoandrew@FSMAIL.NET on wed 16 jun 04
Hello Mike,
As Dave has noted there is a tremendous amount on Brongniart's formula in
the archives.
If you=92ve no objection Ill email you direct with some notes I prepared a
few years ago whilst I was lecturing, although it might take me a couple
of days to find them.
In the meantime it is perhaps worth noting two points from your enquiry:
1) The two factors needed for the calculation are the SG of the dry
materials and the slip density of the glaze.
2) SG of the dry can be found in reference books whilst the slip density
is best measured by weighing a fixed volume as hydrometers are not the
best method due to the high solids and viscosity.
Regards,
Andrew
Lesley Alexander on wed 16 jun 04
Hi Mike,
Select a container, add a specific amount of glaze. Weigh it. Then rinse the
container and measure out and weigh the same amount of water. Subtract the
weight of the water from the weight of the glaze; that's the weight of the
glaze in that specific container. Not much math, but you need to be
consistent in the size and weight measures used. Most convenient to use a
milliliter measuring device and weigh in grams. Good luck, Lesley
Mike Martino on wed 16 jun 04
Dear All (and especially Ivor),
I was discussing the possibility of calculating the weight of the dry
ingredients of an already mixed glaze with a friend the other day. I
suggested that if you have the weight of the wet glaze and a specific
gravity reading from your trusty hydrometer (I'm assuming here that you have
an accurate reading), then you would be able to calculate the weight of the
dry glaze that went into the bucket. Am I mistaken here?
Second, if this is possible to do, what would be the mathematical formula to
achieve it? I'm pretty good at plugging in numbers and hitting ENTER, but
not so hot at coming up with the formula in the first place. In this case
I'm thinking it would be relatively simple, but still beyond my meager math
skills.
Mike
in Taku, Japan
PS: I'm talking round numbers here, I'm not too worried about the mineral
content of the water, or any solubles which have made their way into the
water after the dry ingredients have been added.
Mike Martino on thu 17 jun 04
Hello All,
Oops, I sort of went off half-cocked there gettting into the heat of the
moment and forgetting to check the archives before posting, sorry.
Thanks to everyone who was kind enough to point me in the right direction,
and/or send me their own notes on the subject. Now if I can just find that
calculator....
Mike
in Taku, Japan
| |
|
