BS: Check my math?

Subject: BS: Check my math?
From: John Hardly
Date: 01 Nov 05 - 07:11 PM

I have two glazes that are nearly identical...

Red:
EPK=2500
CF=5270
WH=2130
Talc=400
BA=400
Iron=600

Orange:
EPK=2500
CF=5270
WH=2130
Talc=400
BA=300
Iron=400
Rutile=400

I have a batch of red I mixed last year and I don't need it anymore. I do need the orange. Pretty simple -- all ingredients I need for the orange are in my premixed batch (and, more important, none that I don't need)...

...so how much of all the ingredients do I need to make my red into an orange.

It's only about $5 worth of chemicals.....but it will be put on about $5000 worth of pots! (can't much afford to make a mistake -- that's why I'd like the double-check)

Subject: RE: BS: Check my math?
From: GUEST
Date: 01 Nov 05 - 07:26 PM

BA 100
Iron 200
Rutile 400

Subject: RE: BS: Check my math?
From: GUEST
Date: 01 Nov 05 - 07:28 PM

Ignore that it is wrong

Subject: RE: BS: Check my math?
From: John O'L
Date: 01 Nov 05 - 07:30 PM

I know nothing about glazes, but the red seems to me to have 100 BA too much already.

Subject: RE: BS: Check my math?
From: Allan C.
Date: 01 Nov 05 - 07:32 PM

Sorry GUEST but I believe you got the problem reversed.

Subject: RE: BS: Check my math?
From: Snuffy
Date: 01 Nov 05 - 07:36 PM

You have too much iron in the red mix so you have to make half as much again of the Orange:

EPK=3750
CF=7905
WH=3195
Talc=600
BA=450
Iron=600
Rutile=600

so you need to add:
EPK=1250
CF=2635
WH=1065
Talc=200
BA=50
Iron=0
Rutile=600

Subject: RE: BS: Check my math?
From: Allan C.
Date: 01 Nov 05 - 07:38 PM

John, I may be wrong but I believe what you'd need to do is to enlarge the red batch, say by a factor of 2, while shorting the new batch in BA and iron and adding the appropriate Rutile.

Subject: RE: BS: Check my math?
From: GUEST
Date: 01 Nov 05 - 07:43 PM

You believe wrongly Allan C. I missed what snuffy spotted.

I checked again and camme up with 2 lots of red and 3 orange

EPK 1200
CF 5270
WH 2130
Talc 400
BA 100
Iron 1000
Rutile 1200

Which tallies with Snuffies solution

Subject: RE: BS: Check my math?
From: Cluin
Date: 01 Nov 05 - 07:44 PM

Been a long time since my "intro to Pottery" class and I was never much good at it (sculpture, OTOH...), but I'd say if it was 5 grand worth of pots and you aren't confident of the glaze...

Mix up some new stuff and toss out the old or else put it back on the shelf for a less valuable project.

Subject: RE: BS: Check my math?
From: John Hardly
Date: 01 Nov 05 - 08:04 PM

Thanks guys!

Snuffy has what I came up with. The fact that there was too much iron seems so small on the one hand -- only 100 extra grams in a 10,000G batch .... but since it's percentages, BOY does that alter it, eh?

....and Cluin, you're right -- too much pottery$$$$ to risk. What I do is mix the batch and fire one piece to make sure it's right.

Thanks again!

Subject: RE: BS: Check my math?
From: Allan C.
Date: 01 Nov 05 - 08:25 PM

I love this kind of problem even though I suck at solutions, (q.v..)

Subject: RE: BS: Check my math?
From: pdq
Date: 01 Nov 05 - 08:44 PM

A lot of people see a math problem and glaze-over.

Subject: RE: BS: Check my math?
From: John O'L
Date: 01 Nov 05 - 09:19 PM

If you're going to do a double batch to get the proportions right, will double-glazing follow?

Subject: RE: BS: Check my math?
From: Allan C.
Date: 01 Nov 05 - 09:31 PM

Good one, pdq.

Subject: RE: BS: Check my math?
From: Stilly River Sage
Date: 01 Nov 05 - 10:41 PM

You all sound a little potty. . .

Subject: RE: BS: Check my math?
From: Amos
Date: 01 Nov 05 - 11:13 PM

Don't let them throw you, John; keep your hands on the wheel. I think Snuffy has it right. You do have to compensate for the +100 in the BA.

Doubling the Orange ingredients calls for

EPK=2500x2=5000
CF=5270x2= 10540
WH=2130x2=4260
Talc=400x2= 800
BA=300x2= 600
Iron=400x2= 800
Rutile=400x2=800

Minus the amounts provided by the existing Red leads to:

EPK=2500x2=5000-2500=   2500 added
CF=5270x2= 10540-5270 = 5270 added
WH=2130x2=4260-2130 =   2130 added
Talc=400x2= 800 - 400 =   400 added
BA=300x2= 600 - 400 =      200 added
Iron=400x2= 800 - 600   = 200 added
Rutile=400x2=800 - 0 =       800 added.

The "added" amounts are what you'd have to add to the red to get the doubled batch of orange.

A

Subject: RE: BS: Check my math?
From: Dave the Gnome
Date: 02 Nov 05 - 06:31 AM

I remember from my school daze that to get orange you mix red and yellow - So to change your red glaze to orange throw a couple of lemons in...

:D (tG)

Subject: RE: BS: Check my math?
From: Bunnahabhain
Date: 02 Nov 05 - 08:02 AM

John,
Do you have Iron in the right form to add to your glaze?

I don't know, but I suspect that Iron oxide and metallic iron might have quite different effects in your glaze.

Also, is the 100g of Iron 100g of Fe, or 100 g 0f Fe2O3, or sufficient Fe203 to provide 100g of Fe, or a different Iron oxide?

Subject: RE: BS: Check my math?
From: John Hardly
Date: 02 Nov 05 - 10:29 AM

Yeah, Bunnahabhain, like most potters I use red iron oxide FE2O3. Unlike most potters, I use "red iron precipitate" which has to do with the way the iron oxide is processed so that it is truer to that formula.

...but lemons is a good idea too. In fact, I looked it up in my "The Potter's Dictionary of Materials and Techniques". It says that "rutile" is just another name for "lemon rind". Who knew?

Subject: RE: BS: Check my math?
From: Stilly River Sage
Date: 02 Nov 05 - 03:30 PM

Have you read Lillian Jackson Braun's The Cat Who Saw Red? Interesting ingredient used in that recipe!

SRS

Subject: RE: BS: Check my math?
From: John Hardly
Date: 02 Nov 05 - 05:17 PM

Ash glazes have been great novel fodder!

Actually, legend has it that the first copper red glaze happened by accident as a pig ended up in a chinese potter's kiln before (and therefore, during) a firing of a copper blue/green chun glaze.

The potter never discovered the reason for the beautiful red glaze produced by the additional reduction of the glaze in the early part of the firing. There was nothing left of the pig by the end of the firing.

But the emperor was so taken with this beautiful glaze that he ordered the potter to make more.

Try as he might, the potter could not duplicate the results of the firing. Always green, never red.

Finally desperate and inconsolable at his failure, he threw himself into the burning kiln.

....the emperor got his red glazed pottery. Emperors always get what they want. Potters always work too hard and die.

Subject: RE: BS: Check my math?
From: GUEST,******* *****
Date: 10 Nov 05 - 02:11 PM

Hey I am a 6th grader and I was on Vaca and I dont understand this. Order the fractions from least to greatest (I dotn know if this is right)

#1 1/6 /4 2/5 #2 3/10 2/3 4/5 #3 1/5 3/8 4/5 #4 4/5 7/8 9/10
#5 7/10 5/7 3/4 #6 1/8 3/10 3/5

Please reply to this and answer my ?

Ohh and if you play on Neopets.com please email me my user is panda85234

Subject: RE: BS: Check my math?
From: TIA
Date: 10 Nov 05 - 03:32 PM

As a geologist, I've always thought of rutile as as mineral - titanium oxide. Lemon peel? Interesting.

Subject: RE: BS: Check my math?
From: Jim Dixon
Date: 10 Nov 05 - 06:40 PM

I've checked the math and I agree with Snuffy.

Subject: RE: BS: Check my math?
From: GUEST
Date: 11 Nov 05 - 04:05 PM

Whay can't u yanks spell maths properly or talk proper like what I does..?

:D