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Natas Setiabudhi

Terra Sigillata And Engobe

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Hi all,

 

I just wonder, what are the different between terra sigillata and engobe in context of the result. Because i think, both if burnished, the result is the same. So, we don't have to do long process in making terra sigillata. Better making engobe that more simple. Sorry guys, correct me if i was wrong... Any responses i will accept and really appreciate...

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Engobes are just slips, liquefied clay; they usually are applied on wet to dry greenware. Engobes usually have a lower clay content and also can be used on bisque-fired ware.

Terra sigillata Is a suspension of the very finest clay particles which coats and smooths the surface of greenware ... like silk ... and shines wonderfully when burnished.

 

Slips will not make the surface silky or respond like terra sig to burnishing ... they will just cover it.

 

If you take the time to make terra sig, make a lot of it. It doesn't go bad so you can use it for years.

I keep gold art and red art terra sig on hand but you can make it out of any clay to match your work.

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Guest JBaymore

Most any clay will "burnish". But Sigs are "speciallists" in this.

 

The particle size of Sigs is incredibly much smaller than that in a general slip, due to the levigation/settling process. This particle size allows tighter packing of the particles at a microscopic level when the layer of Sig is applied. These really fine particles also allow a burnish to a much finer surface than a general slip will accomplish as the packing gets tigheter from the pressure and the layering of the flat(ish) platelets get alligned in the same direction.

 

But beyond all this, during the firing process the sintering of the very thin edges of these fine particles cause a harder surface than what will happen with a general slip covering. The clay particles "stick together" at the edges where thay overlap. It is not melting per se,..... but a special concept you might think of as "pre-melting".

 

If you fire your Sigs too hot, you lose this effect as well as some of the burnish qualities.

 

best,

 

...................john

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Dear Natas

 

Try this. I did it for the first time about a year ago. But to make things easy on yourself just put 1 kilo of ball clay in a 5 liter plastic water bottle jug. fill it with clean water add .25% of sodium silicate and .25% of soda ash. That is 2.5grams of each product. make sure it is all mixed up smooth. After 20 hours, poke a hole 1/3 the way up from the bottom and let the top 2/3 of the thin liquid run into a bowl. It will be very watery. discard the bottom 1/3. Be careful during the entire time to not disturb the sediments as they will ruin your terra sig. I apply it thinly and burnish with a sponge enclosed in a very thin grocery story plastic bag.

 

http://digitalfire.c...illata_274.html

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Dear Natas

 

Try this. I did it for the first time about a year ago. But to make things easy on yourself just put 1 kilo of ball clay in a 5 liter plastic water bottle jug. fill it with clean water add .25% of sodium silicate and .25% of soda ash. That is 2.5grams of each product. make sure it is all mixed up smooth. After 20 hours, poke a hole 1/3 the way up from the bottom and let the top 2/3 of the thin liquid run into a bowl. It will be very watery. discard the bottom 1/3. Be careful during the entire time to not disturb the sediments as they will ruin your terra sig. I apply it thinly and burnish with a sponge enclosed in a very thin grocery story plastic bag.

 

http://digitalfire.c...illata_274.html

 

 

Hi.. thank for your responds. I really appreciate it, especially your recipe. First i knew terra sigillata as practical from british ceramic artist who have came to bandung couple years ago. I ignored it at that time..because i think making terra sigillata was complicated process. Now, after given some advices in this forum, i will try it..

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But beyond all this, during the firing process the sintering of the very thin edges of these fine particles cause a harder surface than what will happen with a general slip covering. The clay particles "stick together" at the edges where thay overlap. It is not melting per se,..... but a special concept you might think of as "pre-melting".

 

If you fire your Sigs too hot, you lose this effect as well as some of the burnish qualities.

 

 

john

 

I've been thinking about trying some terra sig, but didn't consider the temperature requirements. What is "too hot"?

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The previous post that looks blank was actually white on white and I could not change it. I apologize for that.

 

 

This is the most simple method for making terra sig that I have found in 40 years. I have used it at workshops where I didn't have a ball mill. No problem. This is from Linda and Charlie Riggs. They are fun to work with.

 

-Marcia

 

Here are the directions:

 

Charlie's Home Brew Sig'

 

I used to think that making terra sig' was a big production and you had to have lots of equipment (hydrometers, wine siphons, graduated cylinders marked in marked millimeters, centimeters, parts per million and billion.....) Yeh, right. Sure you can make the "Perfect Sig" that is smoother than glass using all that stuff but you can pretty much do the same with none of it!

 

This sig' recipe is for all of us non-technophiles and first timers.

 

1) Crack open a cold one.

 

2) Dump in 3 1/2 gallons of water in a bucket.

 

3) Stir in a tablespoon of sodium silicate and/or soda ash.

 

4) Mix in 17 lbs of XX sagger or 9 lbs. OM 4 ball clay* and put the bucket up on a table.

 

5) Finish your cold one and wait a day (20 hours).

 

6) Siphon off the top 1 gallon.** (This includes the little bit of water off the top) This top 1 gallon is your terra sig. You can use immediately or store it for several years.

 

Dump the rest. It's just dirt! "Release it back into the wild."

 

7) If you want, you can sieve it to get the little specks and cat/dog hair out. (200 mesh --or as fine of sieve as you can lay your hands on.)

 

That's it. Dip it, spray it, brush it.

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The previous post that looks blank was actually white on white and I could not change it. I apologize for that.

 

 

This is the most simple method for making terra sig that I have found in 40 years. I have used it at workshops where I didn't have a ball mill. No problem. This is from Linda and Charlie Riggs. They are fun to work with.

 

-Marcia

 

Here are the directions:

 

Charlie's Home Brew Sig'

 

I used to think that making terra sig' was a big production and you had to have lots of equipment (hydrometers, wine siphons, graduated cylinders marked in marked millimeters, centimeters, parts per million and billion.....) Yeh, right. Sure you can make the "Perfect Sig" that is smoother than glass using all that stuff but you can pretty much do the same with none of it!

 

This sig' recipe is for all of us non-technophiles and first timers.

 

1) Crack open a cold one.

 

2) Dump in 3 1/2 gallons of water in a bucket.

 

3) Stir in a tablespoon of sodium silicate and/or soda ash.

 

4) Mix in 17 lbs of XX sagger or 9 lbs. OM 4 ball clay* and put the bucket up on a table.

 

5) Finish your cold one and wait a day (20 hours).

 

6) Siphon off the top 1 gallon.** (This includes the little bit of water off the top) This top 1 gallon is your terra sig. You can use immediately or store it for several years.

 

Dump the rest. It's just dirt! "Release it back into the wild."

 

7) If you want, you can sieve it to get the little specks and cat/dog hair out. (200 mesh --or as fine of sieve as you can lay your hands on.)

 

That's it. Dip it, spray it, brush it.

 

 

That's very clear. I really appreciate it. I really will try 'sig...

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On 6/27/2011 at 12:56 AM, Chris Campbell said:

Engobes are just slips, liquefied clay; they usually are applied on wet to dry greenware. Engobes usually have a lower clay content and also can be used on bisque-fired ware.

Terra sigillata Is a suspension of the very finest clay particles which coats and smooths the surface of greenware ... like silk ... and shines wonderfully when burnished.

 

Slips will not make the surface silky or respond like terra sig to burnishing ... they will just cover it.

 

If you take the time to make terra sig, make a lot of it. It doesn't go bad so you can use it for years.

I keep gold art and red art terra sig on hand but you can make it out of any clay to match your work.

Hello Chris, love your work, Just want to know where I can get Red Art clay, to make some terrasig. Cheers and thanks from lyndy Hill

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7 minutes ago, Lyndy Hill said:

Hello Chris, love your work, Just want to know where I can get Red Art clay, to make some terrasig. Cheers and thanks from lyndy Hill

She hasn't been here in almost 2 years. But any ceramics supply will have redart clay, it is a common ingredient in glazes and clays.

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After sitting in the jar for a long while my terra sig precipitates further and forms a semi-solid base at the bottom and a  watery TS (presumably even thinner) at the top.  When I go to use this terra sig, should I "remix" it, or should I just use the watery top layer and consider it "super refined"?

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On 3/17/2020 at 9:24 AM, Rick Wise said:

After sitting in the jar for a long while my terra sig precipitates further and forms a semi-solid base at the bottom and a  watery TS (presumably even thinner) at the top.  When I go to use this terra sig, should I "remix" it, or should I just use the watery top layer and consider it "super refined"?

Try both and see what happens. 

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Vince Pitelka has a paper on the producing and storing Terra Sig.  :  http://www.vincepitelka.com/wp-content/uploads/2019/05/Super-Fine-Terra-Sigillata-Edited-2019.pdf ,  My memory is that he stores his TS as dry powder and re-suspends the TS when he needs it. 

I have dried TS and re-suspended without problems.   Also used the thick settled slurry and also the 'super fine' liquid.  again either, or a mixture of both will work.   The thick settled slurry puts a 'thick' coat on the ware and the 'super fine' produces a very very very thin coat.   

LT

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