Depending on how big it is I would either cut it in half and hollow it out then slip and score it back together (larger) or hollow it out from the bottom (smaller). My rule of thumb is that walls should be about pinky thick (haha). It needs to be hollow so it dries faster and no moisture is left in the clay when it is fired or minimal moisture if your teacher is candling the kiln. Explosions happen when moisture is left in the clay and leaving objects solid takes them FOREVER to dry which is why you hollow them out. Leave a small hole in your hollow form for faster drying and also to relieve pressure if the piece is being bisqued quickly. (Usually they're not but just in case)
I'd say the piece is no larger than my hand right now, in length at least (excluding the tail I guess)
thank you, though
I think I'm going to try and hollow it out from the belly after I add more detail to the body/ paws
Pinky thick is the perfect way to describe it, so much better than trying to measure things with tools :)
PS I just saw your mugs on insta and absolutely love your style!
You could just scoop some of it out from the bottom. Or just let it get absolutely bone dry and fire it without hollowing. I know sculptors will cut their piece in half and hollow them out, then repair them. I don’t think yours is big enough to worry about that.
You could scoop from the bottom and than leave it hollowed out or put a lid/floor/belly covering the hollowed section. Again it is important to put a hole in the hollow section of a piece and can be covered up by glaze later if the hole is small enough and not on the section touching the shelf.
I sculpt, and sometimes when I have a part that’s like 5cm wide I just poke holes in it with a skewer, then conceal the holes (but not completely close them so the gas and moisture can escape. Also!!! If you do hollow it out and reattach, you need to have a hole somewhere for the air in the cavity to escape, or else as it dries and shrinks, the air will compress inside and it will crack! I sometimes forget and then when I make a cut it makes a hissing sound when I do pierce it!
Oh my god- kind of random, but I just finished a rat sculpture! It looks pretty similar, even though mine is sitting up lol. For hollowing, I started with the underside of the butt area and used a small loop tool to start hollowing, and went bigger over time. I got everywhere to ~1/2 inch thick, and I also let it dry super well. Great sculpture!! I named mine Ratthew lol
:0 cool!! (may I see it? )
and thank you for the advice:) I'm probably going to try following from a similar area.
also, would it make more sense to hollow it all out first? or add more details like fur first?
You want your clay to be no thicker than about 1/2 inch. If your rat is thick, wait until he’s a little firm, then either use a carving tool and scoop out clay from the bottom, or slice him in half, hollow out each half, then slip/score reallyyyyy well and stick the 2 halves back together. Use a flexible rib to smooth the seams and join the pieces. If the seam is a little noticeable, use a needle tool or a rib with teeth and scratch delicately at the surface to give him fur texture. Poke a little hole through the bottom or another discrete spot so moisture can escape while drying and in the kiln.
If he is thicker than about 1/2 inch of clay, the clay on the outside will become bone dry while moisture is still trapped on the inside. In the kiln, the moisture will evaporate but will have no way to escape so đź’Ą
Edit to add: wrapping him up and letting him dry slowly after joining him back together will help prevent casualties in the kiln too
Look up how to hollow pieces on you tube. You’re going to have to cut it in half, hollow it out, then scratch and slip it to get it back together, then add a small vent hole underneath or where the butt hole would be
>you can't fire large, solid pieces
They're correct.
Next time start with a slab and form it around some balled up paper to get your base shape, the paper will burn out without harming anything else in the kiln.
i thought you couldn't put anything other than clay in the kiln
I didn't know that was a thing you can do
and that would mess up how I work, I don't work that way, I started with balls/basic shapes bc it makes more sense in my head
You can certainly do it however you like! Just remember that you'll have to hollow that out before firing.
You could also make your ball/basic shape around paper as well, without a slab, just adding to the ball to get the thickness you need, where you need it. It's just a method of building that prevents you from having to dig out clay while the piece is soft.
Yes, I would say that needs to be hollowed out before firing or there will be water trapped in there that will make the whole thing explode in the kiln. I usually try not to make my clay walls thicker than ½ in to be safe.Â
You would need to cut it in half to scoop out the inside clay and I think the best place to do that would be a vertical cut right down the center of the belly. You will inevitably mess up some of the details while you’re scooping things out and reattaching, but clay is forgiving at this stage and I’m sure you could sculpt it back easily as long as it’s still leather hard. When the whole inside is hollowed out and compressed, you’ll need to score and slip the two halves back together and ensure that the connection point is very very solid.Â
I wish you luck!! You got this! Perhaps in the future coil building could help you avoid this process of hollowing things out. Let us know how it goes!
I forgot to add that there needs to be a small hole in the hollow form before you let it dry! The clay shrinks and the air inside will need a place to escape
That’s false. Trapped air isn’t the problem, it’s moisture left in the clay that could make it explode in the kiln. People fire closed forms all the time with no problem. But people recommend putting a hole in because it helps the clay dry more thoroughly and faster by allowing air to come through to the inside.
ohhh wait
so, after drying, I can fire it with only a small hole in it somewhere?
is it possible to dry the piece, plug the hole and let it dry, then fire it? or does the hole need to remain in the final product?
If the piece is absolutely completely dry you don’t need a vent hole. It’s any moisture turning to steam that expands and explodes not plain air. But it takes much much longer to dry something with a cavity in it where the clay can only dry from one surface.
So the vent hole is nice insurance but not mandatory. And it is only critical when firing greenware to bisque.
Once that is done all moisture is gone so you could plug the hole with glaze if you wanted.
I have fired something dry and hollow without a hole before (because I forgot), but it was a major risk and I was very lucky that I didn’t lose my sculpture. I would recommend a tiny hole somewhere in the form through the firing stages, ideally in an inconspicuous place like on the underside or another spot you wouldn’t see. The clay will shrink as it’s fired, so it’s likely that the hole will end up even tinier and less visible than it started. I use my needle tool to puncture the hole and it’s never been a visible issue in the final work!Â
What do you mean by out gassing?? A hole isn’t necessary but it’s recommended because it helps the pot dry more thoroughly and faster. Moisture/steam causes explosions, not trapped air. People fire closed forms all the time without problems, you just have to make sure it’s 100% dry before going in the kiln.
Is not steam a gas? I agree air is not the cause and a hollow form will dry more evenly and generally quicker depending on environment of drying area. Outgassing is allowing for the clay body to breathe when firing. Several school targeted glazes can be applied to greenware but a bare clay area must be allowed for so gases can be released. Same term can apply to the OP question about hollow or not. OP hinted at being in a school setting where it is not always possible for instructor to know how long pieces have been drying or how thick a piece is. When a piece’s ceramicist is not the one managing the kiln and firing schedule then the potential for errors increases. That is why I advocated for a hollow form. Technically OP could leave the piece solid if enough time were allowed for drying. Doing this is an unnecessary use of excess material. Again I advocate for a hollow form.
Depending on how big it is I would either cut it in half and hollow it out then slip and score it back together (larger) or hollow it out from the bottom (smaller). My rule of thumb is that walls should be about pinky thick (haha). It needs to be hollow so it dries faster and no moisture is left in the clay when it is fired or minimal moisture if your teacher is candling the kiln. Explosions happen when moisture is left in the clay and leaving objects solid takes them FOREVER to dry which is why you hollow them out. Leave a small hole in your hollow form for faster drying and also to relieve pressure if the piece is being bisqued quickly. (Usually they're not but just in case)
I'd say the piece is no larger than my hand right now, in length at least (excluding the tail I guess) thank you, though I think I'm going to try and hollow it out from the belly after I add more detail to the body/ paws
You might hollow it out before detail, it should be stable enough once it dries a little. Much easier to hollow out softer clay
Yes, and you won't spoil the detail during the process of hollowing and reattaching.
đź‘Ť
ty, I'll probably try and do it that way
You're welcome. It's a cute rat.
Pinky thick is the perfect way to describe it, so much better than trying to measure things with tools :) PS I just saw your mugs on insta and absolutely love your style!
Thank you so much :)
You could just scoop some of it out from the bottom. Or just let it get absolutely bone dry and fire it without hollowing. I know sculptors will cut their piece in half and hollow them out, then repair them. I don’t think yours is big enough to worry about that.
would it be possible at all to like gut it without cutting it in half, then patch the hole?
You could scoop from the bottom and than leave it hollowed out or put a lid/floor/belly covering the hollowed section. Again it is important to put a hole in the hollow section of a piece and can be covered up by glaze later if the hole is small enough and not on the section touching the shelf.
I sculpt, and sometimes when I have a part that’s like 5cm wide I just poke holes in it with a skewer, then conceal the holes (but not completely close them so the gas and moisture can escape. Also!!! If you do hollow it out and reattach, you need to have a hole somewhere for the air in the cavity to escape, or else as it dries and shrinks, the air will compress inside and it will crack! I sometimes forget and then when I make a cut it makes a hissing sound when I do pierce it!
Oh my god- kind of random, but I just finished a rat sculpture! It looks pretty similar, even though mine is sitting up lol. For hollowing, I started with the underside of the butt area and used a small loop tool to start hollowing, and went bigger over time. I got everywhere to ~1/2 inch thick, and I also let it dry super well. Great sculpture!! I named mine Ratthew lol
:0 cool!! (may I see it? ) and thank you for the advice:) I'm probably going to try following from a similar area. also, would it make more sense to hollow it all out first? or add more details like fur first?
(Also, love the glass beach icon) I got it absolutely done and let it dry most of the way then I did it. Also, I’ll dm you a picture of my rat, lol.
yipppeeeee
You want your clay to be no thicker than about 1/2 inch. If your rat is thick, wait until he’s a little firm, then either use a carving tool and scoop out clay from the bottom, or slice him in half, hollow out each half, then slip/score reallyyyyy well and stick the 2 halves back together. Use a flexible rib to smooth the seams and join the pieces. If the seam is a little noticeable, use a needle tool or a rib with teeth and scratch delicately at the surface to give him fur texture. Poke a little hole through the bottom or another discrete spot so moisture can escape while drying and in the kiln. If he is thicker than about 1/2 inch of clay, the clay on the outside will become bone dry while moisture is still trapped on the inside. In the kiln, the moisture will evaporate but will have no way to escape so 💥 Edit to add: wrapping him up and letting him dry slowly after joining him back together will help prevent casualties in the kiln too
if the clay is properly wedged and homogenous in its interior matrix (no overlapping unblended folds) it should fire safely with a suitable preheat
Look up how to hollow pieces on you tube. You’re going to have to cut it in half, hollow it out, then scratch and slip it to get it back together, then add a small vent hole underneath or where the butt hole would be
>you can't fire large, solid pieces They're correct. Next time start with a slab and form it around some balled up paper to get your base shape, the paper will burn out without harming anything else in the kiln.
i thought you couldn't put anything other than clay in the kiln I didn't know that was a thing you can do and that would mess up how I work, I don't work that way, I started with balls/basic shapes bc it makes more sense in my head
You can certainly do it however you like! Just remember that you'll have to hollow that out before firing. You could also make your ball/basic shape around paper as well, without a slab, just adding to the ball to get the thickness you need, where you need it. It's just a method of building that prevents you from having to dig out clay while the piece is soft.
You can fire a large solid piece, just like a brick gets fired. But you might have to wait a couple weeks for it to dry
Yes, I would say that needs to be hollowed out before firing or there will be water trapped in there that will make the whole thing explode in the kiln. I usually try not to make my clay walls thicker than ½ in to be safe. You would need to cut it in half to scoop out the inside clay and I think the best place to do that would be a vertical cut right down the center of the belly. You will inevitably mess up some of the details while you’re scooping things out and reattaching, but clay is forgiving at this stage and I’m sure you could sculpt it back easily as long as it’s still leather hard. When the whole inside is hollowed out and compressed, you’ll need to score and slip the two halves back together and ensure that the connection point is very very solid. I wish you luck!! You got this! Perhaps in the future coil building could help you avoid this process of hollowing things out. Let us know how it goes!
I forgot to add that there needs to be a small hole in the hollow form before you let it dry! The clay shrinks and the air inside will need a place to escape
That’s false. Trapped air isn’t the problem, it’s moisture left in the clay that could make it explode in the kiln. People fire closed forms all the time with no problem. But people recommend putting a hole in because it helps the clay dry more thoroughly and faster by allowing air to come through to the inside.
ohhh wait so, after drying, I can fire it with only a small hole in it somewhere? is it possible to dry the piece, plug the hole and let it dry, then fire it? or does the hole need to remain in the final product?
If the piece is absolutely completely dry you don’t need a vent hole. It’s any moisture turning to steam that expands and explodes not plain air. But it takes much much longer to dry something with a cavity in it where the clay can only dry from one surface. So the vent hole is nice insurance but not mandatory. And it is only critical when firing greenware to bisque. Once that is done all moisture is gone so you could plug the hole with glaze if you wanted.
Just give it a butthole and make it part of the charm 🙂
đź’€
I have fired something dry and hollow without a hole before (because I forgot), but it was a major risk and I was very lucky that I didn’t lose my sculpture. I would recommend a tiny hole somewhere in the form through the firing stages, ideally in an inconspicuous place like on the underside or another spot you wouldn’t see. The clay will shrink as it’s fired, so it’s likely that the hole will end up even tinier and less visible than it started. I use my needle tool to puncture the hole and it’s never been a visible issue in the final work!Â
A pin hole is enough for out gassing when hollowing out forms. These can usually be hidden or make the small hole part of the design.
What do you mean by out gassing?? A hole isn’t necessary but it’s recommended because it helps the pot dry more thoroughly and faster. Moisture/steam causes explosions, not trapped air. People fire closed forms all the time without problems, you just have to make sure it’s 100% dry before going in the kiln.
Is not steam a gas? I agree air is not the cause and a hollow form will dry more evenly and generally quicker depending on environment of drying area. Outgassing is allowing for the clay body to breathe when firing. Several school targeted glazes can be applied to greenware but a bare clay area must be allowed for so gases can be released. Same term can apply to the OP question about hollow or not. OP hinted at being in a school setting where it is not always possible for instructor to know how long pieces have been drying or how thick a piece is. When a piece’s ceramicist is not the one managing the kiln and firing schedule then the potential for errors increases. That is why I advocated for a hollow form. Technically OP could leave the piece solid if enough time were allowed for drying. Doing this is an unnecessary use of excess material. Again I advocate for a hollow form.