=?Windows-1252?Q?Tig_Dupr=E9?= on tue 11 sep 07
Dear Claybuds,
=20
I have about 100 different recipes for chrome-tin reds and pinks. =20
Being the curious person that I am, I want to work on what ratios=20
of chrome to tin give the best results for a raspberry red and a=20
sweetheart pink.
=20
My plan is to test two different base glazes with 30 combinations=20
of chrome oxide and tin oxide with each base. The first base is=20
the one from Raspberry in Mastering Cone Six Glazes. The second=20
glaze is Grace Lewis' "B" Base:
=20
Frit 3134 20
Dolomite 20
Kona F-4 20
OM4 Ball 20
Silica 20
-----------------------
Total 100
=20
(Ron Roy recommends altering this to provide more silica by decreasing=20
the dolomite and F4 by 2.5, and boosting the silica to 25.)
=20
In my chrome-tin ratios, I'll use 5%, 6%, and 7% tin oxide, with 0.1%=20
increments of chrome oxide in each batch. The matrix looks like:
=20
Tin oxide 5.0 Chrome oxide 0.1
5.0 0.2
5.0 0.3
5.0 0.4 ... to 1.0
=20
6.0 0.1
6.0 0.2 ... to 1.0
=20
7.0 0.1
7.0 0.2 ... to 1.0
=20
And so on. You get the picture. All will be fired in my electric=20
kiln, at the same time, half in the middle section, half in the=20
upper section, total of 60 test tiles.
=20
One of the things I worked on this weekend was figuring out a way=20
to make all these test glazes more efficiently. My premise is that=20
making 2 groups of 30 batches for a total of 60 batches of 100 grams=20
base glaze just wasn't going to cut it. Too labor-intensive! Two=20
batches of 3000 grams is "more gooder."=20
=20
BUT... Mixing two DRY batches of 3000 grams doesn't properly and=20
evenly disperse all the ingredients. One should wet mix and sieve=20
the glaze to ensure proper dispersion.
=20
But, how do I tell how much colorant to add to each little batch?=20
How much of a liquid glaze do I need to measure out so I know I=20
have 100 grams of DRY materials in the test batch? The answer=20
is elementary. Brongniart's Formula!
=20
A little quick math, and I find that I need to measure out 160=20
grams of wet glaze to ensure that I have 100 grams of dry material,=20
into which I add the tin oxide and chrome oxide.
=20
I=92m asking for a sanity (and a math) check here, before I put on=20
my latex gloves, HEPA dust mask, and start mixing. =20
=20
The results of all this testing will be shared with Claytown=20
community, of course.
=20
Thanks,
=20
Tig Dupre
In Port Orchard, Washington, USA
=
May Luk on wed 12 sep 07
Hello Tig and friends;
When I do color test, I do one big mix like lynn does, except I don't separate them into small cups. I add percentage incrementally mixing with an electric hand blender between dips, and using the same big bowl of glaze.
For your color test, I would do 3 batches. Like this:
Glaze A = 1000 gm base glaze + 50 gm Tin oxide [mix and sieve]
Glaze B = 1000 gm base glaze + 60 gm Tin oxide [mix and sieve]
Glaze C = 1000 gm base glaze + 70 gm Tin oxide [mix and sieve]
Tile #1 [T5/C.1]= Glaze A + 1 gm Chrome Oxide (Blend with electric hand blender)
Tile #2 [T5/C.2]= Above glaze A mixture + 1 gm Chrome Oxide (Blend with electric hand blender)
Repeat until you have tile #10 ending with [T5/C.10]
Tile #11 [T6/C.1]= Glaze B + 1 gm Chrome Oxide (Blend with electric hand blender)
Tile #12 [T6/C.2]= Above glaze B mixture + 1 gm Chrome Oxide (Blend with electric hand blender)
Repeat until you have tile #20 ending with [T6/C.10]
Tile #21 [T6/C.1]= Glaze C + 1 gm Chrome Oxide (Blend with electric hand blender)
Tile #22 [T6/C.2]= Above glaze C mixture + 1 gm Chrome Oxide (Blend with electric hand blender)
Repeat until you have tile #30 ending with [T7/C.10
I don't know if this would be easier or faster. Just another angle in a brainstorming session.
Quick question: Where to get Tin Oxide at a reasonable cost?
Best Regards
May
Kings County
Marcia Selsor on wed 12 sep 07
Maybe if you mixed 1000 dry and mix the dry ingredients well, you =20
could weigh out 50 gram test cups, cut your colorants in half for 50 =20=
vs 100 tests.
It doesn't take much for a test tile. For 1000 grams, you'd get 20 =20
tests. I put these 50 gram batches into a blender..I use 2 old =20
blenders when doing glaze tests. It just goes faster. Then screen =20
them in a tiny Talisman sieve if there are undesolved ingredients.
Marcia Selsor
http://marciaselsor.com
On Sep 11, 2007, at 8:57 AM, Tig Dupr=E9 wrote:
> Dear Claybuds,
>
> I have about 100 different recipes for chrome-tin reds and pinks.
> Being the curious person that I am, I want to work on what ratios
> of chrome to tin give the best results for a raspberry red and a
> sweetheart pink.
>
> My plan is to test two different base glazes with 30 combinations
> of chrome oxide and tin oxide with each base. The first base is
> the one from Raspberry in Mastering Cone Six Glazes. The second
> glaze is Grace Lewis' "B" Base:
>
> Frit 3134 20
> Dolomite 20
> Kona F-4 20
> OM4 Ball 20
> Silica 20
> -----------------------
> Total 100
>
> (Ron Roy recommends altering this to provide more silica by decreasing
> the dolomite and F4 by 2.5, and boosting the silica to 25.)
>
> In my chrome-tin ratios, I'll use 5%, 6%, and 7% tin oxide, with 0.1%
> increments of chrome oxide in each batch. The matrix looks like:
>
> Tin oxide 5.0 Chrome oxide 0.1
> 5.0 0.2
> 5.0 0.3
> 5.0 0.4 ... to 1.0
>
> 6.0 0.1
> 6.0 0.2 ... to 1.0
>
> 7.0 0.1
> 7.0 0.2 ... to 1.0
>
> And so on. You get the picture. All will be fired in my electric
> kiln, at the same time, half in the middle section, half in the
> upper section, total of 60 test tiles.
>
> One of the things I worked on this weekend was figuring out a way
> to make all these test glazes more efficiently. My premise is that
> making 2 groups of 30 batches for a total of 60 batches of 100 grams
> base glaze just wasn't going to cut it. Too labor-intensive! Two
> batches of 3000 grams is "more gooder."
>
> BUT... Mixing two DRY batches of 3000 grams doesn't properly and
> evenly disperse all the ingredients. One should wet mix and sieve
> the glaze to ensure proper dispersion.
>
> But, how do I tell how much colorant to add to each little batch?
> How much of a liquid glaze do I need to measure out so I know I
> have 100 grams of DRY materials in the test batch? The answer
> is elementary. Brongniart's Formula!
>
> A little quick math, and I find that I need to measure out 160
> grams of wet glaze to ensure that I have 100 grams of dry material,
> into which I add the tin oxide and chrome oxide.
>
> I=92m asking for a sanity (and a math) check here, before I put on
> my latex gloves, HEPA dust mask, and start mixing.
>
> The results of all this testing will be shared with Claytown
> community, of course.
>
> Thanks,
>
> Tig Dupre
> In Port Orchard, Washington, USA
Marcia Selsor
http://marciaselsor.com
The Goodsons on wed 12 sep 07
Dear Tig,
How exciting to read of your testing. I like to test too, so I love to
read about others that like it too.
To double check- Did you
1 weigh your bucket
2 mix your large batch of dry material (for 30 tests/3000g) (60
tests/6000g)
3 add water to the density that you like/ mix, sieve
3 weigh bucket with wet glaze in it
4 subtract off the weight of the bucket
5 divide by 30 or 60 (now you have weigh of 100g of dry glaze with
water added)* In your case this is 160g of wet material?*
6 weigh new small container / add that amount to amount you got when
you divided by 30 or 60
7 now you have the weight of the testing container when filled with glaze
Yikes!! I am making something simple sound hard. Is this what you did?
Please keep me posted on how it is going. And let me know exactly how
you came to your measurement of 160g!! I would think this would vary
from glaze to glaze depending on the how much water is added. You are
inspiring me to get back at it- as I have spent too much time this
summer doing other things.
Have a good day,
Linda Goodson
Lincolnton, NC
goodfun@charter.net
PS I am going to have to google this Brongniart??
On Sep 11, 2007, at 8:57 AM, Tig Dupré wrote:
>
>> Dear Claybuds,
>>
>> I have about 100 different recipes for chrome-tin reds and pinks.
>> Being the curious person that I am, I want to work on what ratios
>> of chrome to tin give the best results for a raspberry red and a
>> sweetheart pink.
>>
>> My plan is to test two different base glazes with 30 combinations
>> of chrome oxide and tin oxide with each base. The first base is
>> the one from Raspberry in Mastering Cone Six Glazes. The second
>> glaze is Grace Lewis' "B" Base:
>>
>> Frit 3134 20
>> Dolomite 20
>> Kona F-4 20
>> OM4 Ball 20
>> Silica 20
>> -----------------------
>> Total 100
>>
>> (Ron Roy recommends altering this to provide more silica by decreasing
>> the dolomite and F4 by 2.5, and boosting the silica to 25.)
>>
>> In my chrome-tin ratios, I'll use 5%, 6%, and 7% tin oxide, with 0.1%
>> increments of chrome oxide in each batch. The matrix looks like:
>>
>> Tin oxide 5.0 Chrome oxide 0.1
>> 5.0 0.2
>> 5.0 0.3
>> 5.0 0.4 ... to 1.0
>>
>> 6.0 0.1
>> 6.0 0.2 ... to 1.0
>>
>> 7.0 0.1
>> 7.0 0.2 ... to 1.0
>>
>> And so on. You get the picture. All will be fired in my electric
>> kiln, at the same time, half in the middle section, half in the
>> upper section, total of 60 test tiles.
>>
>> One of the things I worked on this weekend was figuring out a way
>> to make all these test glazes more efficiently. My premise is that
>> making 2 groups of 30 batches for a total of 60 batches of 100 grams
>> base glaze just wasn't going to cut it. Too labor-intensive! Two
>> batches of 3000 grams is "more gooder."
>>
>> BUT... Mixing two DRY batches of 3000 grams doesn't properly and
>> evenly disperse all the ingredients. One should wet mix and sieve
>> the glaze to ensure proper dispersion.
>>
>> But, how do I tell how much colorant to add to each little batch?
>> How much of a liquid glaze do I need to measure out so I know I
>> have 100 grams of DRY materials in the test batch? The answer
>> is elementary. Brongniart's Formula!
>>
>> A little quick math, and I find that I need to measure out 160
>> grams of wet glaze to ensure that I have 100 grams of dry material,
>> into which I add the tin oxide and chrome oxide.
>>
>> I'm asking for a sanity (and a math) check here, before I put on
>> my latex gloves, HEPA dust mask, and start mixing.
>>
>> The results of all this testing will be shared with Claytown
>> community, of course.
>>
>> Thanks,
>>
>> Tig Dupre
>> In Port Orchard, Washington, USA
>
> Marcia Selsor
> http://marciaselsor.com
>
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>
The Goodsons on wed 12 sep 07
Dear Clay "People",
I too have mixed my glaze tests from dry ingredients in the past and
weighed them out dry into the smaller test amounts and then added the
water. I love the idea of the blender, thank you Marcia. Tig suggests
mixing it wet and then dividing it up and I see his point about mixing
and sieving. ( I have done this too with smaller amounts) Are there
any "scientific" thoughts here? I would think that no matter which way
we do it- there is room for not having it totally consistent. (dry- not
mixed completely enough) (wet-all the settling that could occur while
you are pouring out so many small amounts). This discussion has me
wondering how others do this process?
Sincerely,
Linda Goodson
Lincolnton, NC
goodfun@charter.net
Marcia Selsor wrote:
> Maybe if you mixed 1000 dry and mix the dry ingredients well, you
> could weigh out 50 gram test cups, cut your colorants in half for 50
> vs 100 tests.
> It doesn't take much for a test tile. For 1000 grams, you'd get 20
> tests. I put these 50 gram batches into a blender..I use 2 old
> blenders when doing glaze tests. It just goes faster. Then screen them
> in a tiny Talisman sieve if there are undesolved ingredients.
>
> Marcia Selsor
> http://marciaselsor.com
>
Lynn Goodman Porcelain Pottery on wed 12 sep 07
> I would think that no matter which way
> we do it- there is room for not having it totally consistent.
> (dry- not
> mixed completely enough) (wet-all the settling that could occur while
> you are pouring out so many small amounts). This discussion has me
> wondering how others do this process?
Linda,
If I have a lot of color tests with one base glaze (a fairly common
occurrence in my studio), I mix a big batch on the thick side, with
enough bentonite to deter settling, and divide it among a bunch of
cups. Granted, it's not the most accurate approach, but I can follow
up any promising results with a more formal test mixing.
Incidentally, when I'm testing a promising color, I always mix at
least 300 gms--that way, I know that any slight problems with
accuracy measuring very small percentages will be minimized.
Lynn
Lynn Goodman
Fine Porcelain Pottery
Cell 347-526-9805
www.lynngoodmanporcelain.com
Dan Semler on thu 13 sep 07
Hi Tig,
There is a method that will allow you to make just a handful of =20
glazes and add the chrome/tin in a progressive manner dipping tiles as =20
you go that will give you a very good idea of what you want without =20
making 30 glazes up. You could do it with 3 per base. This is =20
documented in Robin Hopper's Ceramic Spectrum. As people have pointed =20
out most methods of shortcutting involve increasing inaccuracy, but =20
honestly as you are merely doing a search, close enough is very likely =20
good enough. Just mix up three base glazes containing 5, 6 and 7 % =20
chrome ox. Use 300 g batches to cover up for loss with each tile =20
dipped to minimise inaccuracy. Then add 1% tin ox to each and dip =20
tiles. Then add another 1% and dip another set of tiles and proceed =20
until done. Just a quick beat with a stick blender each time and =20
you're done. If you look in Ceramic Spectrum you'll see a neat way to =20
get approx. measurements of the %ages without weighing each one =20
individually too.
Thx
D
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