Building a wet slab bonsai pot

[ABCarve]

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[Pitoon]

@ABCarve making that pot is no joke. A lot of steps involved.

 

[ABCarve]

@ABCarve making that pot is no joke. A lot of steps involved.

So far it’s taken 2-1/2 hours, not including making the plug and rib. Probably another hour of cleanup. Funny, it takes just a little longer to make a 20” pot. I wonder how long it takes to pack a plaster mold? I’ve never done that. I like this method in that you can make multiple ribs for a plug and multiple plugs for one rib. Great versatility with a minimum of space.

 

[Pitoon]

Very cool! I'm currently in the process of making some plaster molds myself. It seems like it's taking forever to get them done. I have a bag of plaster #1, but it went bad so next week I'll be picking up a fresh bag to continue on with the process.

 

[Vinnie Charity]

First two extruded side pots. These were made with the same die. Still learning, but has cut time almost in half. Cutting a more complex die today. I’ll try to photograph the process next to show some benefits of it. The pot on the left is 20”.
View attachment 412953

I’m very curious on how this process works. I’m assuming it extrudes in “2D” and then the extruded strips are formed into pot shapes?

Great looking pots by the way!!!

 

[andrewiles]

This thread inspired me to try making a pot. My clay skills were pretty good in kindergarten but are rusty after a few years. I took a daylong class at a local studio and have access to their facilities and 28inch kiln.

I didn't document much, but I mostly followed the approach laid out by @ABCarve. Some differences:

• I have no wood carving skills but I do have a small 3d printer. Inkscape + Blender + the printer's slicer software yielded some ribs. For anyone with a printer this is a really convenient way to go. Pro tip: learn what a "manifold" is before you try printing your model. Took me hours to figure out why my ribs wouldn't print right.
• I learned the hard way that paper from Home Depot, used for wrapping moving items, turns to mush when wet and is NOT a good releaser for the mold. I don't have any newspaper but I found that freezer paper works really well, with the shiny side facing the clay. I suspect it's better than newspaper. I wrapped the bottom of the mold, tightly, like you would a present, and I had minimal issues with imprints on the clay. Thinking about trying Saran wrap as well.
• I had a hard time making smooth edges with a thin rib. Since I could print what I wanted I made my profile rib 2 inches wide. This prevented it from tilting when dragged across the clay to create the edge profile. This only works well at the last cleanup step, or you get stuck grabbing too much clay. See the first photo below. Bottom profile piece is 2 inches wide, like the upper right piece lying sideways. Upper left piece is a thin rib for the top lip.

I think the rib and mold prep work are key. I have no clue how @ABCarve does this prep work in mere hours, but for mortals it's a bit longer. Worth it though.

Hardest part for me are the feet. I can't figure out how to make them look nice without lots of cleanup. I think maybe I need to let the clay harden a bit for that part.

No firing yet. My one day class didn't really get that far. So, yeah, I've got a few more steps to learn.


My ribs. Standard PLA.


On the mold, face down after initial scraping. I'm using a local clay called "Eclipse", which apparently fires to grayish black.


Finished product. Sort of. I hear your have to cook it or something...


Feet make me sad. I think I spent more time on these guys than the rest of the pot.


Thanks @ABCarve for the detailed info earlier in the thread. Extremely helpful for total pottery noobs like me.

 

[ABCarve]

This thread inspired me to try making a pot. My clay skills were pretty good in kindergarten but are rusty after a few years. I took a daylong class at a local studio and have access to their facilities and 28inch kiln.

I didn't document much, but I mostly followed the approach laid out by @ABCarve. Some differences:

• I have no wood carving skills but I do have a small 3d printer. Inkscape + Blender + the printer's slicer software yielded some ribs. For anyone with a printer this is a really convenient way to go. Pro tip: learn what a "manifold" is before you try printing your model. Took me hours to figure out why my ribs wouldn't print right.
• I learned the hard way that paper from Home Depot, used for wrapping moving items, turns to mush when wet and is NOT a good releaser for the mold. I don't have any newspaper but I found that freezer paper works really well, with the shiny side facing the clay. I suspect it's better than newspaper. I wrapped the bottom of the mold, tightly, like you would a present, and I had minimal issues with imprints on the clay. Thinking about trying Saran wrap as well.
• I had a hard time making smooth edges with a thin rib. Since I could print what I wanted I made my profile rib 2 inches wide. This prevented it from tilting when dragged across the clay to create the edge profile. This only works well at the last cleanup step, or you get stuck grabbing too much clay. See the first photo below. Bottom profile piece is 2 inches wide, like the upper right piece lying sideways. Upper left piece is a thin rib for the top lip.

I think the rib and mold prep work are key. I have no clue how @ABCarve does this prep work in mere hours, but for mortals it's a bit longer. Worth it though.

Hardest part for me are the feet. I can't figure out how to make them look nice without lots of cleanup. I think maybe I need to let the clay harden a bit for that part.

No firing yet. My one day class didn't really get that far. So, yeah, I've got a few more steps to learn.


My ribs. Standard PLA.
View attachment 416893

On the mold, face down after initial scraping. I'm using a local clay called "Eclipse", which apparently fires to grayish black.
View attachment 416895

Finished product. Sort of. I hear your have to cook it or something...
View attachment 416896

Feet make me sad. I think I spent more time on these guys than the rest of the pot.
View attachment 416897

Thanks @ABCarve for the detailed info earlier in the thread. Extremely helpful for total pottery noobs like me.

Looks mighty fine for a first timer. There are a lot of nuances of the technique that I just can’t put into photos. We’re going to try and create a video next weekend to hopefully address some of these. I’m sure you’ll develop some of your own procedures as you progress. Please share them here.
I’ve thought of food wrap and gonna give it a try. It may have a problem with the rib tearing it and bunching up or may shrink away from the form if it’s cut as the butcher paper is. @sorce has suggested trimming a credit card for a rib.

 

[penumbra]

I have worked with clay for years and I could not make a pot this nice off the cuff. Nice job.

 

[andrewiles]

I have worked with clay for years and I could not make a pot this nice off the cuff. Nice job.

Thanks! I'm going to start another one tonight. The studio folks say the largest size I should make is 19" x 11", so I just made a simple mold of that size. Something about not wanting to straddle a shelf to avoid cracking? I'll have to ask. Since the kiln is 28" I'm hoping to eventually get closer to that on the longest diagonal. I'd like to make some pots for some forest plantings I have coming up.

 

[penumbra]

You could buy a full shelf for your use if you want to make larger pots. It is a good idea not to straddle shelves but I have done it without a problem.

 

[ABCarve]

False foot suiban

 

[Pitoon]

False foot suiban

Impressive! How will you prevent the bottom in the center from sagging when firing? Support blocks? Wadding?

 

[ABCarve]

Impressive! How will you prevent the bottom in the center from sagging when firing? Support blocks? Wadding?

It’s a false foot. It created by a small beveled cut the lower band and the bottom. The bottom sits directly on the shelf. I will put grog under it so it’ll slide as it shrinks in the kiln. The grog acts as little ball bearings.

 

[Pitoon]

It’s a false foot. It created by a small beveled cut the lower band and the bottom. The bottom sits directly on the shelf. I will put grog under it so it’ll slide as it shrinks in the kiln. The grog acts as little ball bearings.

Now I see it, that's very slick! You think without adding the grog would it crack in the kiln as it shrinks?

 

[ABCarve]

Now I see it, that's very slick! You think without adding the grog would it crack in the kiln as it shrinks?

Possibly. It’s easy to do. The false foot is the same trick as I use for daizas. It makes it look thinner than it really is.

 

[Pitoon]

Possibly. It’s easy to do. The false foot is the same trick as I use for daizas. It makes it look thinner than it really is.

The false foot is really convincing.

 

[penumbra]

The false foot is really convincing.

It really is. I'd like to see a close up from another angle

 

[ABCarve]

It really is. I'd like to see a close up from another angle

 

[ABCarve]

Now I see it, that's very slick! You think without adding the grog would it crack in the kiln as it shrinks?

The grog is only used in the glaze firing.

 

[andrewiles]

Very cool. How thick did you roll out the bottom slab?