So, what’s the deal with porcelain for bonsai pots?

Colorado

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I just ordered a pottery wheel. I’ve been slab building for about a year now but zero experience with throwing on a wheel.

It seems like I’ll need to use a different clay body for the wheel that what I’m using now for slab building.

Internet research suggests that porcelain can be good for throwing due to its high plasticity. So, what are the advantages and disadvantages of using porcelain for bonsai pots? Would I be better off with a stoneware with minimal grog?

Would love to hear anyone’s opinions. Would be very thankful if @NaoTK @Pitoon @penumbra have time to weigh in on this, or anyone else!
 

hemi71cuda

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What clay are you using for slab building that wouldn’t work on the wheel? All the common commercial stonewares, even the ones with grog, are throwable. Grog is good, especially when you want to start throwing bigger pieces or combat sagging during firing. My biggest piece of advice for throwing is COMPRESSION!!! Porcelain moves different on the wheel. It can still be used for bonsai pottery but a stoneware may prove to be more durable in use.
 

Colorado

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What clay are you using for slab building that wouldn’t work on the wheel? All the common commercial stonewares, even the ones with grog, are throwable. Grog is good, especially when you want to start throwing bigger pieces or combat sagging during firing. My biggest piece of advice for throwing is COMPRESSION!!! Porcelain moves different on the wheel. It can still be used for bonsai pottery but a stoneware may prove to be more durable in use.
Thanks for the input! For slab building I am using a couple of commercial clay bodies - Laguna B-3 Brown and Redstone.

I had read online (🤪) that throwing clays typically have less grog, but that’s why I wanted to come here for some actual bonsai-specific advice!

Would certainly be much easier/convenient to just use the same clay for everything!
 

Colorado

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What clay are you using for slab building that wouldn’t work on the wheel? All the common commercial stonewares, even the ones with grog, are throwable. Grog is good, especially when you want to start throwing bigger pieces or combat sagging during firing. My biggest piece of advice for throwing is COMPRESSION!!! Porcelain moves different on the wheel. It can still be used for bonsai pottery but a stoneware may prove to be more durable in use.
And, great looking tree in your avatar pic, by the way!
 

BrightsideB

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Large grog particles can catch to your hand when throwing. And your piece can become uneven. And your hands will be exfoliates for sure. But it’s what I primarily throw because it is the most durable for outside pieces. You should try the clay you already use. My main focus is vitrification and I always talk to a company about the history of the particular clay and it’s durability with the outdoor elements. I’ve seen a lot of misinformation that cone 10 is the best. But it is not unless the criteria for vitrification and water absorption of less then 1% in the fired clay body is met. Plenty cone 6 clay bodies can perform better then cone 10 outside nowadays. But throwing a clay body that has small grog particles is nice and so much easier. It’s easier to get those nice edges people like in bonsai pots.
 

hemi71cuda

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Thanks for the input! For slab building I am using a couple of commercial clay bodies - Laguna B-3 Brown and Redstone.

I had read online (🤪) that throwing clays typically have less grog, but that’s why I wanted to come here for some actual bonsai-specific advice!

Would certainly be much easier/convenient to just use the same clay for everything!
Those clays will throw fine. Your real challenge will be throwing in general. Took me about two years to become mediocre but at least feel a little bit competent.
 

NaoTK

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Porcelains are traditionally higher in kaolin, are more vitreous, are less plastic, are more translucent, and fire higher than stonewares. These days you can make porcelains that defy these trends, and also white clays that look like porcelain. For bonsai the glassy nature of porcelain makes it more prone to thermal shock and the vitreous/high shrinkage makes it more prone to warping in the kiln. Above about 12" it becomes impractical to use true porcelains for bonsai pots.

As others have said you can throw any clay if it is plastic enough.
 

BrightsideB

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Porcelains are traditionally higher in kaolin, are more vitreous, are less plastic, are more translucent, and fire higher than stonewares. These days you can make porcelains that defy these trends, and also white clays that look like porcelain. For bonsai the glassy nature of porcelain makes it more prone to thermal shock and the vitreous/high shrinkage makes it more prone to warping in the kiln. Above about 12" it becomes impractical to use true porcelains for bonsai pots.

As others have said you can throw any clay if it is plastic enough.
An employee at the ceramic shop near me showed me that white clay that simulates the look of a porcelain and I though that was really cool! I think porcelain makes great accent pots. I don’t believe it met the criteria for me to make outdoor pieces with though. I can’t remember.
 

Pitoon

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@Colorado just to give you an idea throwing with porcelain is like throwing with cream cheese..... almost the same consistency. Now that you're getting a wheel soon. The main thing to get down is centering your clay on the wheel.
 

Colorado

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Porcelains are traditionally higher in kaolin, are more vitreous, are less plastic, are more translucent, and fire higher than stonewares. These days you can make porcelains that defy these trends, and also white clays that look like porcelain. For bonsai the glassy nature of porcelain makes it more prone to thermal shock and the vitreous/high shrinkage makes it more prone to warping in the kiln. Above about 12" it becomes impractical to use true porcelains for bonsai pots.

As others have said you can throw any clay if it is plastic enough.
Thanks, Nao! This is exactly the type of advice I was hoping for. I think most of the pots I’ll be making will be in that 12” range, so it sounds like porcelain wouldn’t be a very good option for what I’m trying to do.
 

Colorado

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An employee at the ceramic shop near me showed me that white clay that simulates the look of a porcelain and I though that was really cool! I think porcelain makes great accent pots. I don’t believe it met the criteria for me to make outdoor pieces with though. I can’t remember.

Good point, maybe I’ll do some accents in porcelain some day once I get some experience with wheel throwing!
 

Colorado

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@Colorado just to give you an idea throwing with porcelain is like throwing with cream cheese..... almost the same consistency. Now that you're getting a wheel soon. The main thing to get down is centering your clay on the wheel.

Centering the clay on the wheel…I will make sure to keep that in mind when I’m getting started. Thanks!

I must confess that I’ve spent quite a bit of time watching Instagram videos on how to throw, so I have some basic background understand of how it’s supposed to work…but I am sure there is no substitute for hands-on practice!
 

Pitoon

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I must confess that I’ve spent quite a bit of time watching Instagram videos on how to throw, so I have some basic background understand of how it’s supposed to work…but I am sure there is no substitute for hands-on practice!
I too have watched plenty of videos. It's not as easy as it looks. What I found helpful is to brace your dominant elbow whether sitting or standing. Centering slow is good to start and keep the clay lubricated.
 

Colorado

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I too have watched plenty of videos. It's not as easy as it looks. What I found helpful is to brace your dominant elbow whether sitting or standing. Centering slow is good to start and keep the clay lubricated.
I am expecting plenty of failures and a steep learning curve 😂

that’s okay I will have fun practicing!

Yes it’s going to be a totally new ball game from slab building with all the water…I’m going to have the wheel out in my garage workshop so if I make a mess, no big deal.
 
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