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Mossyrock

Slip Settling

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I work in low fire to cone 6 oxidation and have a white slip recipe that works well for both. The problem is that within a few days, the slip settles to the bottom of the container into a clump (for lack of a better word) and it takes a lot of time and effort to put it back into a nice usable suspension. Is there anything I can add that will keep this from happening or is that just a characteristic of slip? Here's the recipe:

 

6 Tile 1500 g

OM4 Ball Clay 1000 g

Custer Feldspar 1250 g

Silica 1250 g

Zircopax 300 g

 

I mix the dry ingredients and keep in an airtight container. When I need to mix a batch of slip, I weigh out 1000 g of the dry mix, add 4 tsp. Sodium Silicate, then add water and sieve several times. It's great until I don't use it for several days. Thanks for any help.

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Thats a lot of clay to keep up.

I have had super results with a product called Magma sold at Big Ceramic store.com in glaze use I'm sure it would help in your slip-The key to slip casting is long amounts of time power mixing before use.If its just slip for pots try the magma.

Mark

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I am decorating with it, not casting. And I am brushing it on the pots. It takes several days for the slip to settle to the bottom and become unusable until it is stirred, stirred, stirred.....and then stirred again. Thanks again for any help.

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I am decorating with it, not casting. And I am brushing it on the pots. It takes several days for the slip to settle to the bottom and become unusable until it is stirred, stirred, stirred.....and then stirred again. Thanks again for any help.

 

 

Try the Magma it keeps bricks in suspension.

PS use only a very small amount and mix it in hot water.

 

Mark

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Also.....you can dissolve a small amount of epsom salts in a small amount of very hot water and pour the water into the slip after it has set up, but before you stir it. Let it sit for awhile and then stir. You may need a little more, but try to stir it first to be sure. Once it is usable again, it will not set up like that again.

 

Before I get in trouble, let me say for sure that this works fantastic for glazes. However, I don't see any reason it wouldn't work as well with slip. I would sure use it on mine, just to make sure. Does anyone else know anything about this?

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Also.....you can dissolve a small amount of epsom salts in a small amount of very hot water and pour the water into the slip after it has set up, but before you stir it. Let it sit for awhile and then stir. You may need a little more, but try to stir it first to be sure. Once it is usable again, it will not set up like that again.

 

Before I get in trouble, let me say for sure that this works fantastic for glazes. However, I don't see any reason it wouldn't work as well with slip. I would sure use it on mine, just to make sure. Does anyone else know anything about this?

 

 

I'll give this a try Janie. It's not like I will ruin a large batch if it doesn't work. If I've got about 5 cups of slip, about how much Epsom salts would you use? You said a small amount.....I'm thinking a teaspoon? I'm still going to order the Magma, but in the meantime, I'll give this a shot.

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For decorating only I would try the epson salts<div>for 5 cups which is a very small amount-use hot water to dissolve and a tablespoon of salts.

This may help.

The thrift store blender I us e all the time in my studio- as well for glaze making</div><div>Slip settles and will need mixing-so get a small mixer for a hand held drill for your slip.

<div>Mark</div>

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What Mark said. About a TBSP epsom salts in about 1/4 cup very hot water. A TBSP would also work for a larger amount, too.

 

I went to yard sales until I found a blender, a juicer, and an electric skillet (for melting wax). Total cost was less than $10.00.

 

 

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Okay ~janie,

 

At first I thought of one of those "which word doesn't fit?" type of puzzles, with blender, juicer and electric skillet; juicer being the one that didn't seem to fit in the context (to non-clay folks, the answer would be all of them fit ...in the kitchen.) So what kind of clay magic can we do with a juicer? Is this a manual or electric juicer? I may have to be on the lookout for one of these, or if it is a manual juicer, I have my next project.

 

John

 

http:\\wynhillpottery.weebly.com

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O.K.;

You are going to laugh. Mark has accused me of being the guy who talks the airplane down after the pilot has had a heart attack. Here goes;

Bear in mind that I am Canadian, and we are a helpful bunch. Don't hold it against me.

I looked at your slip formula and saw that you have WAY too much silica in there and that is what is causing it to settle.This may take me a moment to explain, but bear with me.

1.Your formula-

Tile 6 1500

Ball 1000

Custer 1250

Silica1 1 250

Zircopax 300

 

2.I dropped off the zeroes,leaving you with

Tile 6 150

Ball 100

Custer125

Silica 125

 

Total 500

3. I left out the zircopax for the moment as it is there to make the slip whiter.

4. If you divide each of your four materials by your total of 500 grams, this is what you get;

Tile .30

Ball.20

Custer.25

Silica .25

Total 100

add Zirco at .6

 

If you look at the percentages, you have 25% silica, and 25% Custer, both very heavy materials.

So, I dropped the silica down to 10% and recalculated your recipe for you. I have not tested this, but you should make a 100 gram batch and see if it settles.

Tom's White Slip

Tile 6 35

Ball 24

Custer29

Silica 12

Total 100

Zirco 6

 

This should work better for you.LET ME KNOW HOW IT GOES.oops, caps lock on again.

TJR.

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TRJ

You really did your homework on this one-I think she will be able to land it now

 

JLowes

I have no idea about the juicier in the studio?

 

If your feet hurt soak them in hot water with epsom salt-old timers trick

 

Mark

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TRJ

You really did your homework on this one-I think she will be able to land it now

 

JLowes

I have no idea about the juicier in the studio?

 

If your feet hurt soak them in hot water with epsom salt-old timers trick

 

Mark

 

 

Mark;

I actually had to get up off my chair and get a calculator for this one. Hope she lands without a scratch.

TJR.

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The juicer is a handheld device for mashing up fruit for drinks. It reminds me of an upside down helicopter, in that the blade is on the bottom and is plunged into a cup, glass, or pot of some sort to reduce the fruit to a smoothie consistancy. They are about $12.00 new at WalMart, but I found mine at a yard sale for $1.00. The lady told me she got it for her birthday, and it made her mad then and does every time she looked at it, so decided to get rid of it. LOL

 

TJR, I think you are right. I think I might try this myself.

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The juicer is a handheld device for mashing up fruit for drinks. It reminds me of an upside down helicopter, in that the blade is on the bottom and is plunged into a cup, glass, or pot of some sort to reduce the fruit to a smoothie consistancy. They are about $12.00 new at WalMart, but I found mine at a yard sale for $1.00. The lady told me she got it for her birthday, and it made her mad then and does every time she looked at it, so decided to get rid of it. LOL

 

TJR, I think you are right. I think I might try this myself.

 

 

Janie;

Here is my analogy. If I have a pain in my hip, I go to the doctor.He/she looks at the PROBLEM, rather than masking it with pain killers. Yes, you can buy juicers at Walmart for $12.00, or $1.00 at the garage sale, and you can buy fry pans and toaster ovens as well. But ultimately you have a slip with far too much sand in it.It will still settle. You can throw Epsom salts at it and change the electrolytes, and I can put a band-aide on my hip. Am I going to do that? No.

Today is the anniversary of the Gimli Glider. The pilot glided a huge plane with 65 passengers on board, completely empty of fuel. There was an article in the Globe and mail today.

TJR.

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Any slip will settle over time. We use a cordless power drill with a paint mixer to resuspend the particles in our slip every time we get ready to cast. We also use a commercial defloculant, adding as necessary to get the consistency we like.

Remember-

If you aren't part of the solution, you're part of the precipitate!!

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This is getting fuzzy so lets get it right-

For slip work with molds(slip casting) the mixer is usually mounted on a motor with a stainless shaft with 2-to 3 impellers sits on top of the slip tank.

I have two of these units also have a pump that you can drop on the side of bucket with a gas type hose nozzle that pumps whatever (usually slip).

You will not need to defloculant your decorating slip

If one needs to ever use Davon it works best

I had a simi large slip cast business at one time

 

The mixer I spoke about to mix a little decorating slip fits in a electric drill I have bunch of various sizes-They have 1/4 and 3/8 and 1/2 inch shafts and vary in lengths and head diameters -made by outfits like Jiffy mixer or Hanson-you can buy these at ceramic supply houses or online-These are a must have for potters who make glazes

I use them to mix glazes every week or slip occasionally(blue moon )

The 3rd item is called a blender its what Jimmy Buffet uses to make margaritas with-

I do not call it a juicer as I have one of those that makes juice from say carrots or apples or whatever- These are made by outfits like Champion or Jack LaLane who swam the queen mary across the harbor by his teeth- and was one buff dude

A blender is for mixing drinks making milk shakes or whatever- Made buy just about every appliance maker on this planet. I do not know what Wall Mart sells them for as I never go to one -even though one just got built in our county.I do know I get mine at a Great thrift store on Widbey Island in Wa, when I do the Anacortes Art Festival every year(my 20th year this year) -they cost very little money-I always have a few of them as I burn them up.

I use them in the studio to mix stubborn materials in glaze making like zinc or making small test batches of glaze usually every week

I hope this clears this up.

I can take some photos if one needs more clarity on the mixers or who Jimmy Buffet is ?

Mark

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O.K.;

You are going to laugh. Mark has accused me of being the guy who talks the airplane down after the pilot has had a heart attack. Here goes;

Bear in mind that I am Canadian, and we are a helpful bunch. Don't hold it against me.

I looked at your slip formula and saw that you have WAY too much silica in there and that is what is causing it to settle.This may take me a moment to explain, but bear with me.

1.Your formula-

Tile 6 1500

Ball 1000

Custer 1250

Silica1 1 250

Zircopax 300

 

2.I dropped off the zeroes,leaving you with

Tile 6 150

Ball 100

Custer125

Silica 125

 

Total 500

3. I left out the zircopax for the moment as it is there to make the slip whiter.

4. If you divide each of your four materials by your total of 500 grams, this is what you get;

Tile .30

Ball.20

Custer.25

Silica .25

Total 100

add Zirco at .6

 

If you look at the percentages, you have 25% silica, and 25% Custer, both very heavy materials.

So, I dropped the silica down to 10% and recalculated your recipe for you. I have not tested this, but you should make a 100 gram batch and see if it settles.

Tom's White Slip

Tile 6 35

Ball 24

Custer29

Silica 12

Total 100

Zirco 6

 

This should work better for you.LET ME KNOW HOW IT GOES.oops, caps lock on again.

TJR.

 

 

Wow, TJR, thank you for putting so much time and effort into your reply. I don't have chemicals here; I mix at a friend's studio in another town, then pay him for the chemicals used. So the next time I'm there, I will mix a batch of slip according to your recipe and let you know how it works. I realize that it too will probably settle, but I'm hoping it won't settle into that horrible clump. This forum is such a wonderful resource for information.

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O.K.;

You are going to laugh. Mark has accused me of being the guy who talks the airplane down after the pilot has had a heart attack. Here goes;

Bear in mind that I am Canadian, and we are a helpful bunch. Don't hold it against me.

I looked at your slip formula and saw that you have WAY too much silica in there and that is what is causing it to settle.This may take me a moment to explain, but bear with me.

1.Your formula-

Tile 6 1500

Ball 1000

Custer 1250

Silica1 1 250

Zircopax 300

 

2.I dropped off the zeroes,leaving you with

Tile 6 150

Ball 100

Custer125

Silica 125

 

Total 500

3. I left out the zircopax for the moment as it is there to make the slip whiter.

4. If you divide each of your four materials by your total of 500 grams, this is what you get;

Tile .30

Ball.20

Custer.25

Silica .25

Total 100

add Zirco at .6

 

If you look at the percentages, you have 25% silica, and 25% Custer, both very heavy materials.

So, I dropped the silica down to 10% and recalculated your recipe for you. I have not tested this, but you should make a 100 gram batch and see if it settles.

Tom's White Slip

Tile 6 35

Ball 24

Custer29

Silica 12

Total 100

Zirco 6

 

This should work better for you.LET ME KNOW HOW IT GOES.oops, caps lock on again.

TJR.

 

 

I personally don't see anything wrong with her original formula. It's just a basic white formula- half clay, quarter silica, quarter feldspar. I've used this slip in my studio for the last 15 years with no problem. I think the issue is probably that it is too watery. Mixing it up a little bit thicker would help a lot.

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Brenda, Have you considered reducing the amount of sodium silicate that you are adding to this recipe? It may be over-deflocculating the slip at 4t per 1000g, which would cause the slip to settle quickly like making a terra sigillata . Adding the epsom salts (very small amount, pre-dissolved) will work by counteracting the overage of sodium silicate...but you could also just cut back on that part from the start. If you need to improve the brushability at that point, look at David Pier's TechnoFile on Binders form Nov 2011 for more info.

 

That much clay in the recipe should hold up that much fledspar and silica no problem. But if you are repelling the clay particles from each other with all the SS, those large pieces will drop to the bottom of the bucket.

--Tina

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Brenda, Have you considered reducing the amount of sodium silicate that you are adding to this recipe? It may be over-deflocculating the slip at 4t per 1000g, which would cause the slip to settle quickly like making a terra sigillata . Adding the epsom salts (very small amount, pre-dissolved) will work by counteracting the overage of sodium silicate...but you could also just cut back on that part from the start. If you need to improve the brushability at that point, look at David Pier's TechnoFile on Binders form Nov 2011 for more info.

 

That much clay in the recipe should hold up that much fledspar and silica no problem. But if you are repelling the clay particles from each other with all the SS, those large pieces will drop to the bottom of the bucket.

--Tina

 

 

Ditto. I missed that part in your description. Definitely deflocculate less!

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