How to Make Your First Ceramic Teacup

This project has started more than one year ago in winter when I was feeling sick and I had to drink a lot of tea. But I had a problem, that all the standard teacups were too small and I had to constantly refill them. I was searching for a properly sized cup but I wasn't able to find an appropriate one.

Because of that I decided to end this misery and make a bigger cup myself :)

I never did ceramic pottery before in my entire life. This project was one big learning curve but it ended up awesome at the end.

Feel free to watch the video above which describes the workflow sou it will be easier for you to follow this Instructable.

And in this Instructable I will further describe the details step by step.

For this project you don't need any special tools other than basic DIY tools. Heck you can do it even without power tools). The only tool you (and I) definitely don't have at home is the oven or Kiln that goes up to 1100°C (2000°F) in order to bake the clay into ceramics.

Luckily I have one friend that does pottery as a hobby and had kiln at home and he was happy to bake my cups. Otherwise you should ask around if anyone is doing pottery professionally or even if anyone is casting aluminum or doing something that includes a high temperature oven. There are a lot of artists and crafters around, you just need to ask. There are also pottery associations that have workshops and machines available.

As for materials you will need:

(Links are affiliate links for the products I did not explicitly use and tested since I sourced my materials locally. I am pasting these links for products that are similar to the ones I used for your reference and research. You can order your parts elsewhere, but this affiliate links help me to loose less money with each project :) ).

- casting plaster https://amzn.to/37UEq9X (I used around 10 lbs of plaster for my mold)

- temporary filler -

https://amzn.to/3bL3MIl

I used casting sand which is used for metal casting, but you can use regular clay or some similar material. More details in next steps.

- slip casting clay:

https://amzn.to/2O6OZQ2

or even porcelain slip for more premium look

https://amzn.to/3aYR1Ld

- transparent glaze:

https://amzn.to/2MB8H6o

Or any color you like

- underglaze pencils:

https://amzn.to/3r0wNWR

These are very expensive, but if you are good at drawing they are definitely worth it :) Normal pencils don't work as they burn away at high temperatures.

I 3D modelled a pretty basic cup shape. I eyeballed the curves to look nice. It came out great!

Here is a 3D model:

https://www.thingiverse.com/thing:4781523

I also included a "lid" which is used to make an edge which makes it easier to cut away a nice lip on the top side of the cup. More on this later.

You can model your own design, or you can copy an existing cup or an item you have around. Just keep in mind 2 things:

- the finished ceramic cup will be smaller than your model as the clay shrinks when baking (more on this later)

- the shape must allow so that it can pop out of the plaster mold without chipping the plaster. I made 2 part plaster mold since I wanted to have a handle and a narrower lip. If a cup shape would be more like a cone, you could simplify your life and make one-piece mold - it would pop out of the top of the one-piece mold. Look at the cross section of my handle on an image above. A shape like this slides out of the mold much easier. Avoid 90 degree angles because you will ruin your mold when removing the cup model out.

I made a simple wooden box to act as a frame for my mold.

You don't want to make the box too small, because you want at least an inch thick plaster walls around your model.

You need to have some volume of plaster around your module which is needed to suck moisture from you slip clay.

Then I filled the bottom half with a temporary filler. I used casting sand which is usually used to make molds for casting aluminium, but I have seen most of the people use regular clay.

You want to fill it to exactly half of the cup, so the mold halves will be symmetrical and the cup will be able to slip out easily, without chipping the plaster. Otherwise the plaster would "hug" or "catch" the cup and it won't come out.

I also added three positioning pins for easier positioning both halves of the molds.

Use proper casting plaster and not that "house wall repair plaster" which hardens instantly and you will not be able to even pour it out of the bowl. Don't ask me how I learned that :)

When mixing the water and plaster, you should mix the powder into the water and not vice-versa.

The mix ration should be around 1 part water to 1.5 part plaster. First you slowly put the plaster into the water and then you should wait a couple of minutes for the plaster to absorb into the water and then you shoud begin to stir it for a minute or two.

I mixed plaster with a cordless drill and a cement mixing attachment.

You don't need to hurry too much, but don't be to slow either or the plaster will harden before you pour it.

Then pour it in slowly.

Allow the plaster to dry for an hour or two and then disassemble the sides of the box and sweep away the sand underneath.

The plaster is now solid but still very workable. You can now add some chamfer to the outer edges so it will not chip when handling.

Use a hammer slowly tap the lid out and then try to loosen the cup out of the mold gently. Try not to chip the plaster too much.

The process is more of less the same , but instead of using temporary filler(sand or clay), you put the first half of the mold back in the box and pour the second half on top of it.

Apply some soap on the mating surface so the molds will not fuse together.
Add the positioning pins on top of the existing ones, so both halves will have pins embedded.

Mix the plaster again and pour it as in the previous step and remove the cup from it.

Then let the plaster to dry for at least a week. You want it very dry so it will be able to absorb the water from clay.

When the plaster has fully dried, join both halves of the mold together with some elastic band or clamps.

If you bought pre-mixed slip, you can just mix it well enough and pour it in the mold.

I used a bit older slip clay that was already used several times and I needed to check the specific gravity/density which should be around 1.7 (100ml of slip weighs 170g). If its to thick, add water.

I also had to sift the clay so no hard lumps were present when I poured it in the mold.

You should leave the slip in the mold around 5 minutes to 45 minutes. This time is affected by the dryness of the plaster mold and the density of your slip.

You will see the level of the slip drop as the moisture is absorbed by the plaster and the clay will harden a bit at the perimeter of the mold. Every now and then check how thick the walls have become. The longer you let it soak, the thicker the walls of the cup will become.

When you think its enough, pour it out and let it dry to the point where the clay feels like a "normal clay".

The clay will shrink a bit when drying. Don't let it dry for too long as it will become brittle when dry. The best is the consistency of a regular sculpting clay. At this point, the cup has a technical term "greenware" as it is raw.

Using a bent knife(bend the tip of your least favourite knife) cut the top part out, so you get a nice lip. This is why we made that top 3D printer lid that sticks over the cup.

Split the mold in half and gently take the cup out of the mold. Your hands will leave some fingerprints but its OK, because you are going to fix that later. The lip also does not need to be perfect for now.

Fix only the big imperfections.

With the same mold you can make maximum 2 cups at the time. Then you need to let it dry again for a couple of days, else it will not suck the moisture out of the slip any more.

As the cups dry, they will become brighter in color and EXTREMELY BRITTLE.

The best thing is to dry them in the pottery kiln/oven itself, so you will not need to move them at all.

I didn't have the kiln at home. My friend does some hobby pottery and has a kiln and I delivered the cups to him when they were moist. Dry cups would not survive the transport by car!

If you are searching for a kiln, there are relatively a lot of artists and pottery clubs around where you could use an kiln like that.

Then the kiln is started. The cups need to reach the temperature of around 1100°C (2000°F). The oven should slowly rise the temperature to that point and then cool down even more slowly to prevent the cups from cracking.

The whole process takes around 8-12 hours.

Then the cups become hard ceramic, like the store bought ones. Now, the technical term for them is a "biscuit".

Fired pots are very easy to sand and you should take some regular sandpaper and sand all the surfaces.

Sanded surfaces will better absorb the glazing in the following steps and the end product will look more professional.

I wanted to have my logo on the cups, so I printed a sticker template and applied the glaze with a brush.

Then I removed the sticker and I was left with a nice logo.

But be careful. Glazing is just very fine particles of glass suspended in water and the drawn image can get easily brushed off if touched.

If you want to have more detailed image on your cup (and you know someone who can draw) you can use underglaze pencils and draw a very detailed image on the cup before applying the glaze.

I can't draw anything better than stick figures, so I asked my sister who can really draw and she have drawn me a perfect Instructable robot just for this occasion :)

If you have enough glaze, you can dip the cups in the glaze. This makes the most perfect and even finish.

I dipped the cups in two stages - first I dipped the handle and then let it dry for a few minutes so that the glaze was dry enough to touch. Then I grabbed the cups at the handle and dipped the full cup.

Glazing is just fine particles of glass suspended in water and you need to mix it thoroughly and then quickly dip the cup in it before the particle settle again on the bottom.

If your glaze is too thin, not much of it will stick to the cup. If it is too thick, you will get an extremely thick layer of glaze on your cup which is also not good. You will need some experimenting to make it just right. Don't ask me how I know this. My first glazing left a 5mm thick monster layer of a glaze on the cup, and my second glazing didn't leave anything at all :)

If you don't have enough glaze, you can apply it with a brush. Try to apply it as evenly as possible for the best results.

After dip glazing, don't forget to wipe the glaze off the bottom of the cup with a wet rag, or the glaze will cause the cup to stick to the kiln forever :)
I used a special wax to protect the bottom, but the cup still stuck a little to the kiln :)

The cups need to be fired in a kiln again. The temperature is the same - around 1100°C or 2000°F and the whole process takes around 8-12 hours.

Again the heat up and cool down should be slow so the cups don't crack. If you cool down the cup too quickly, or you open the kiln before it cooled down to room temperature, the glazing could crack. But it baking again and applying some new glaze on the cracks will fix it.

I mentioned that the cups shrink a lot when firing. On the image above you can see that the shrinkage is significant! Keep this in mind when designing your cup model.

It affects the volume significantly. Initially the cup capacity was planned to be around 0.7L and now when baked is a bit more than 0.5L.

Now after many hours of hard work you can finally sit down, pour yourself a cup of tea and admire your masterpiece! :)

I hope you liked this Instructable!

Don't forget to watch the youtube video on the top of the instructable, where you will see me going through everything described here.

I do a lot of Instructables and DIY themed YouTube videos.

If you want to stay in touch on what I am currently working on:

You can subscribe to my YouTube channel(click the bell icon to get notified, since I only post approximately once a month):

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If you would like JT teacup and can't make your own, I am also experimenting with merchandise and you can buy it on the link below (did it just for fun, not expecting anyone to actually buy it :) )

https://www.redbubble.com/shop/ap/72403141

And don't forget to follow me on Instructables and vote for this Instructable in the "Sculpt & Carve" contest :)

Cheers!

JT