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Mixed Glaze, Looks Thin, But Brushed Thick Suggestions?


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#1 Benzine

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Posted 12 January 2013 - 05:13 PM

I have some Continental Clay glazes, I buy in powdered form, then mix with water, for my classroom. I'm fairly certain I got the proportions right, but it is difficult to apply, because it dries and clumps as soon as they are brushed on.
The glazes settles in the bottle, fairly quickly as well.
So what can I do, to make the glazes more brushable? In the past, I used a suspender additive, that didn't seem to help much.

The glazes, as I mentioned, is from Continental Clay. They are low fire glazes; Federal Blue, Italian Green and Tarnished Brass.

Any advice is appreciated. I really like these colors, and the students enjoy them as well, but are hesitant to use them, because of the "clumpiness".
"Anything worth believing, is worth questioning"

#2 bciskepottery

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Posted 12 January 2013 - 09:05 PM

Maybe add some brushing medium, gum arabic, or glycerine to improve brushability. I think I read somewhere (can't recall source) that you can also use a bit of mineral oil/baby oil . . . a cheap alternative and might be worth a test.

#3 TJR

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Posted 12 January 2013 - 09:08 PM

Benzine;
I know the glaze Federal Blue-it is really blue! The problem with mixing from dry is that you have to sieve the glaze, which is a pain.If you don't have too much of the powdered stuff, I would move to glazes in jars. Life is too short to spend your teaching time sieving.
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#4 Benzine

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Posted 12 January 2013 - 09:56 PM

Benzine;
I know the glaze Federal Blue-it is really blue! The problem with mixing from dry is that you have to sieve the glaze, which is a pain.If you don't have too much of the powdered stuff, I would move to glazes in jars. Life is too short to spend your teaching time sieving.
TJR.


You're right, it is BLUUUUUUE. That's one reason both myself, and the students, like it. I've found a combination, using it, that I really like as well. I mostly use Amaco bottled glazes, besides the three from Continental Clay I mentioned.

Exactly, what is involved in sieving? Is this something I would have to do, each time I mixed the glaze, or each time it was used?
"Anything worth believing, is worth questioning"

#5 weeble

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Posted 12 January 2013 - 10:10 PM

I was buying powdered glazes for a while from Laguna, and I inherited a formula from a previous instructor that we used to mix them up for brushing. I forget exactly what the amounts were (its been a few years, and the info is in a file somewhere), but it involved mixing CMC gum with the water and letting it sit 24 hours, then mixing powdered bentonite with the dry glaze powder before mixing powder and liquid and letting the mixture sit over another night. Continental might have a similar suggestion. Sieving simply involves running the mixed glaze through a fine sieve to break up the clumps. You can get a glaze sieve from most ceramic suppliers, but we only really have to sieve a glaze after the first mixing and then if it sits for a few months.

I agree with TJR, futzing with dry glazes isn't worth the savings. We now buy jar glazes.

Also, if your glaze is drying too fast as you apply it, spritz the piece with water or dampen it before you start applying the glaze, it makes life SOOO much easier.
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#6 Mark C.

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Posted 12 January 2013 - 10:57 PM

How about putting them is blender (kitchen type) and mixing them each for 4-5 minutes on high with a glaze suspender in them then putting them in jars.
The mixer will make them where they do not need sieving.

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#7 Benzine

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Posted 12 January 2013 - 11:22 PM

How about putting them is blender (kitchen type) and mixing them each for 4-5 minutes on high with a glaze suspender in them then putting them in jars.
The mixer will make them where they do not need sieving.

mark


Ah, I like that suggestion. It just so happens, that I have a couple old blenders, sitting in my storage room, from a previous instructor. I think she used them for paper making, but they haven't been pulling their weight in years, so it may be time to put them back to work.

Any suggestion on a glaze suspender? The stuff I used in the past was just a whitish looking powder, also from Continental.
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#8 Lucille Oka

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Posted 13 January 2013 - 06:32 AM

I have some Continental Clay glazes, I buy in powdered form, then mix with water, for my classroom. I'm fairly certain I got the proportions right, but it is difficult to apply, because it dries and clumps as soon as they are brushed on.
The glazes settles in the bottle, fairly quickly as well.
So what can I do, to make the glazes more brushable? In the past, I used a suspender additive, that didn't seem to help much.

The glazes, as I mentioned, is from Continental Clay. They are low fire glazes; Federal Blue, Italian Green and Tarnished Brass.

Any advice is appreciated. I really like these colors, and the students enjoy them as well, but are hesitant to use them, because of the "clumpiness".


To what temperature are you bisque firing? A little harder ware may help eliminate some of that absorption.
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"For God so loved the world that He gave His only begotten Son, that whosoever believeth in Him should not perish but have everlasting life".

#9 Benzine

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Posted 13 January 2013 - 01:25 PM


I have some Continental Clay glazes, I buy in powdered form, then mix with water, for my classroom. I'm fairly certain I got the proportions right, but it is difficult to apply, because it dries and clumps as soon as they are brushed on.
The glazes settles in the bottle, fairly quickly as well.
So what can I do, to make the glazes more brushable? In the past, I used a suspender additive, that didn't seem to help much.

The glazes, as I mentioned, is from Continental Clay. They are low fire glazes; Federal Blue, Italian Green and Tarnished Brass.

Any advice is appreciated. I really like these colors, and the students enjoy them as well, but are hesitant to use them, because of the "clumpiness".


To what temperature are you bisque firing? A little harder ware may help eliminate some of that absorption.


Cone 04 bisque. All the other, bottle glazes, absorb well. It's just the powdered ones, I mix, that are the problem.

I'll try the blender method, Mark mentioned, and see how that goes. Everyone will think I'm making smoothies in the Art Room.
"Anything worth believing, is worth questioning"

#10 ayjay

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Posted 13 January 2013 - 04:22 PM

I use a fair few brush-on glazes at home, and have buckets of dipping glaze at night school, there is (understandably) a considerable difference in using a brush-on glaze and brushing on a glaze intended for dipping.

Along with the other advice I would also suggest you look at the brushes you're using, they need to be able to hold a fair bit of glaze, not so important for a purpose made brush on glaze but for a dipping glaze it's critical, check the thickness of the glaze on the finished item, it's too easy to end up with a thinner than required glaze layer if you're brushing a dipping glaze.

#11 Lucille Oka

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Posted 13 January 2013 - 04:35 PM

I was interested in the bisque firing temperature at cone 04. It just sounds as if your ware maybe too porous.
There are differences in the cone 04 temperatures even though it is just 56 degrees difference across the chart it is a telltale difference. I realize attempting to achieve specific temperatures can be difficult with a KilnSitter but adjustments can be made with a slight movement of the junior cone toward the thicker end in the sitter. A harder bisque can inhibit too much glaze absorption. But test it and see if this can work for you.

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#12 Benzine

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Posted 23 January 2013 - 11:39 PM

Mark, thanks again for the tip about the blender.

I finally had a chance to get those glazes mixed up, and it appears to have worked wonders. I didn't add any suspender, at this time, as I don't have any. I'll probably wait and order some, later this year, as that's when I normally put in my purchase orders.
"Anything worth believing, is worth questioning"

#13 Mark C.

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Posted 24 January 2013 - 01:22 AM

One of the best suspenders I have found as well as it tested as one of the best in a CM article a year ago is Magma
heres a link to a supplier which I am not affiliated to.
I pre mix some and keep in a sealed container for use when needed-follow instructions from a sheet on the web site as its shipped with no info.
http://www.bigcerami...plies/magma.htm
Mark
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#14 Nancy S.

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Posted 24 January 2013 - 01:58 PM

I'll try the blender method, Mark mentioned, and see how that goes. Everyone will think I'm making smoothies in the Art Room.


Mmmmm! Glaze smoothies! Posted Image

I read one potter's blog entry not too long ago about how she added Astroglide in lieu of glycerine, to make the glazes flow more smoothly (it's mostly glycerine). Posted Image

#15 TJR

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Posted 24 January 2013 - 02:57 PM


Benzine;
I know the glaze Federal Blue-it is really blue! The problem with mixing from dry is that you have to sieve the glaze, which is a pain.If you don't have too much of the powdered stuff, I would move to glazes in jars. Life is too short to spend your teaching time sieving.
TJR.


You're right, it is BLUUUUUUE. That's one reason both myself, and the students, like it. I've found a combination, using it, that I really like as well. I mostly use Amaco bottled glazes, besides the three from Continental Clay I mentioned.

Exactly, what is involved in sieving? Is this something I would have to do, each time I mixed the glaze, or each time it was used?


Benzine;
Sorry to not get back to you with an answer to your question about sieving. This is a process more for studio glazes. I mix my studio glazes by the 10,000 gram batch. This works out to approx. 5 gallons. For my school situation, I have an 80 mesh sieve. I pour the liquid glaze from one bucket, through the sieve into another clean bucket. At home, I would then pour it back through a 100 mesh sieve[smaller size holes.] For school, I only use the one sieve, and sieve one time. For smaller batches, [jar size], you could buy a kitchen sieve at the dollar store and sieve through that.[probably a 40 mesh]
The mesh size comes from the number of holes per square inch. The smaller the hole in the screen, the more per square inch-so a 100 mesh screen would be finer than an 80 mesh.This is one of those things in life that is easier to show, rather than type.
TJR.

#16 neilestrick

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Posted 24 January 2013 - 04:29 PM

To make a nice brushing mix, you'll first have to make a gum solution. Add 2 tablespoons of CMC Gum to a gallon of water and let it sit overnight. Then mix it thoroughly using a stick blender or regular blender. Use the gum solution in place of 1/3 of the water when making the liquid glaze. It's also a good idea to add 2% bentonite to the dry mix. Dry mix it very well before adding water or the bentonite will clump up. The CMC gum can get eaten up quickly by bacteria since it's an organic material, so you'll need a preservative. The easiest way to go is to add 0.25% (1/4 of 1%) copper carbonate or copper oxide to the dry mix. It shouldn't show in your glaze, and will help keep bacteria at bay. It's not the world's best preservative, but works pretty well. Adding 1% Vee Gum T will improve brushability even more, but it's an expensive ingredient. After mixing your glaze with the gum solution and water, screen it through an 80 mesh sieve. It only takes a couple of minutes. If you go the blender route, make sure you recombine all the blender batches before putting them into smaller containers.
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#17 Benzine

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Posted 24 January 2013 - 06:50 PM

One of the best suspenders I have found as well as it tested as one of the best in a CM article a year ago is Magma
heres a link to a supplier which I am not affiliated to.
I pre mix some and keep in a sealed container for use when needed-follow instructions from a sheet on the web site as its shipped with no info.
http://www.bigcerami...plies/magma.htm
Mark


That looks like good stuff. I've never purchased anything from that store, but I'm familiar with it. Thanks again Mark.
"Anything worth believing, is worth questioning"




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