In late May I found out that I needed to make five dozen custom tiki cups for an event in mid-July. I've never made a tiki cup before, although I'd thought about it, so I wasn't at all set up to create any, let alone more than 50 in about seven weeks. Potters will understand, that's a very short timeline for someone who only does pottery part-time, especially considering firing schedules.

This meant that a lot of more standard methods of making them weren't a possibility. Creating new plaster molds for casting would take too long, especially since I don't regularly do casting and am not set up for it. Sculpting the cups individually would take even longer. What could I do to put designs on them that would be relatively fast, both to engineer and to make each cup?

I asked on a ceramics forum (Clay Buddies) for ideas, and several people (including Tim See) suggested that stamps were my best bet. I hadn't had a lot of luck, though, stamping individual cups will on (or off) the wheel. So after some tinkering, I tried a different approach that I'd used with other textures; instead of bringing the stamp to the cup, I'd bring the cup to the stamp. I needed a texture mat.

TPU is flexible printable plastic. I've been finding it works much better for stamps than rigid plastic, both because you can bend it around pieces and also because it sticks a bit less. It's perfect for texture mats. So I found some cartoons of tiki faces on a clipart site, modified them to make them simpler and more geometric, and turned one into a texture mat, which I printed in black TPU.

The next step was to create a wooden form for the inside of each cup, which could be used to roll the cup across the texture mat without losing its shape. I made mine from a 2" diameter post and inserted part of a broom handle for control. I did not want to 3d print the inside-cup dowel, both because plastic sticks to wet clay, and because I was concerned about strength.

Next, I had to throw a bunch of perfectly cylindrical cups, with interiors that were 2.25" diameter and 5.5" tall to match the dowel. This was a bit harder than it sounds; I hadn't thought about the fact that my hands are too large for a 2.25" diameter cup, and as a result I had to finish each cup using a throwing stick on the inside.

The next step was to roll the cups on the mats to make the tiki faces. The first batch of 6 cups I ended up turning into regular mugs, because I found out (the "hard" way) that the clay needed to be quite soft to take an impression, like just 12-15 hours after throwing.

I learned a few things with this first trial. First, it was quite difficult to get a good impression if the design, like this one, had any large blocky shapes. Also those squares at the top with sharp corners really dug into the clay, ruining some cups. But I felt like I was on the right track.

So I did two new designs, which were composed only of lines, and gave fairly even design coverage over the whole height of the cup. I also started dusting the designs with dry clay to make them stick less.

This worked a lot better. Those designs really popped and were clear all over the cup, and would look good once glazed.

Next I repeated that several dozen times. And then drying, and firing, and glazing. Tip: if you do use dry clay to prevent a stamp from sticking, make sure you brush off all the loose dry clay once the piece hardens. I didn't do that on all the cups and it ruined the glaze on a few.

I glazed them all using translucent glazes (two celedons and two others) which would do the best job of emphasizing the tiki designs. They were all done, not just on time for the event, but actually two weeks early. Yay!

I'll definitely use this technique again, although I'll make some changes. Some padding on the dowel would probably be good. Also, maybe a cup form that was a bit wider and shorter to speed up throwing. But it worked pretty well.

I was having a serious problem with my new plaster bats. They're tall enough to raise the throwing surface above the edge of the splash pan on my standing wheel. This was resulting in a fair amount of slip spatter on the walls:

It's a clay studio, so a little spatter was fine, but this would just keep building up and eventually become a silica hazard. I needed a way to make the edge of my splash pan just a inch and a half taller, without hampering my arms while throwing. Including throwing wide plates.

With some trial-and-error, I designed a clip that would slide onto the rolled edge of the Brent wheel splash pan. I printed five of them.

Then I went to the hardware store and grabbed a plastic splash guard, the kind you normally attach to the bottoms of doors. That slid neatly in to give me the 1.5 inches of extra splash guard I needed ... without getting in the way of my arms.

These clips should be useful for anyone who owns a Brent wheel. If you want to use them for trimming, you could put in a much taller piece of plastic. If you improve the design, please share!

I like to make "shot glasses" for doing glaze tests, and to sell off as a $2 item. Given how disposable these are, though, I can't be bothered with throwing and trimming them, so I turned to my trusty extruder to just extrude a tube, cut it into short bits, and cap them off to turn them into little shot glasses. Easy, right?

But, I quickly found that the commercial hollow extruder plates created a tube that was way too thick and asymmetrical to boot. The problem is the design; standard hollow dies are made by having a metal "bridge" holding the center piece in place. This doesn't permit careful, exact placement to make nice 3 or 4mm thick walls. Since I 3D print my extruder plates these days, that got me thinking about printing dies for hollow forms.

Most other artists going down this line of experimentation make the mistake of trying to recreate the shape of the flat commercial die with the bridge exactly. Not only are there a number of mechanical problems with this (PLA or ABS are not strong enough for a bridge), but it's also very limited thinking. We can make any shape we want on the 3D printer; why limit ourselves to reproducing the exact shape of commercial dies that are cut from sheets of polyetheline?

So, I started playing around with designs. The first thing I decided was that the die needed to be flat on top. One of the other disagreeable parts of the metal bridge design has always been that you can't use all the clay in the extruder because some of it will be caked up around the bridge. Further, I wanted the center piece to be printed permanently in place, so that I could have thin walls that I knew would not be thicker on one side or the other because the center piece moved around.

So I printed a 2cm tall hollow die with four printed supports holding the center piece in place. The supports were less than 1cm high, so the clay could go past them and out the tube. This produced four separate quarters of a tube, up until the supports broke with the pressure and the die came apart. Improvements were needed.

So first thing, the clay needed to be squished together after it got past the supports. It occured to me that if, instead of a tube shape, I had a kind of hollow cone shape, then after the clay got past the supports it would compress and the four divided portions would re-merge before exiting the die.

Second, I needed to reenforce the supports. I made them into hollow tubes so that I could insert a 3mm brass rod, which would be stronger than the plastic (I tested 2mm, but it wasn't strong enough).

This gave me the design I was looking for. Here's how the final die looks.

Here's the die being printed. You can see those hollow support tubes in progress. It's being printed upside-down, so that there doesn't need to be any support material.

The die was strong, and produced a strong, fused tube. And this design concept is cleary reproduceable for any type of hollow die.

I squished this one a bit cutting it, but look at those even sides!

Since it's hard to cut the clay tube without squishing it, I also designed a miter for cutting it with a wire.

Now, there is one drawback to this die design: it's hard to clean, and you need to clean it right after use while the clay is still soft. I found out the hard way that it's extremely difficult to remove dried clay from the complex interior shape.

Here's my designs on Thingyverse. If you create additional hollow dies using this approach, please share with me there or on Clay Extruding and Rolling Group.

Hopefully this post will help you break out of flat thinking when designing 3D printed dies.

When I learned how to put handles on things ... and generally join pieces of clay together ... back in the late Middle Ages, I learned it the way folks have done it for millenia. Score heavily with a sharp tool (like fork), slip, and score again. Then press together and try to wipe off all the mucky slip that's now everywhere. It's the tried and true method and I guarantee you as you're reading this, some pottery student somewhere is learning slip-and-score to attach a handle to a mug.

Sometimes "venerable" also means "outdated", and this is one of those times. Stop slipping and scoring. There's a new way, and by "new" I mean actually more than a decade ago, but somehow most potters haven't heard of it yet.

Hopefully, this will help.

You see, slip-and-score originates in the belief that clay doesn't want to stick together. And there's sometimes that's true -- like when there's a gap, or if the two pieces of clay are different levels of dryness. But most of the time, clay wants to stick. In fact, if it's wetter than leather hard, it's difficult to make it not stick. The other idea of the slip is to have plenty of mush so that no air bubbles get trapped between the two pieces, which can encourage cracking while drying. But the double scoring, if anything, makes air bubbles more likely. It definitely makes accidentally making a hole in the vessel more likely.

So, what's my alternative? A toothbrush and "magic water".

Y'see, when you've got a handle and a still pliable mug body, they want to stick together. You just need to make sure that the two surfaces come into maximum contact, and for insurance you add just a little deflocculant (a chemical that dissolves clay) to make the clay "stickier". Some folks use vinegar or saliva for this, but what works even better is a chemical solution called Magic Water popularized by potter Marian Williams. Magic water is a very weak solution of deflocculants. I make up 1/2 gallon at a time:

• 1/2 gallon distilled water
• 1.5 Tbs liquid sodium silicate
• 1.5g powdered soda ash

To encourage maximum adhesion, I dip an old toothbrush in the magic water solution, and rough up both surfaces that will be in contact. This works like barge cement; once you'd magic watered both surfaces, they'll stick and be hard to pull apart (so make sure you place that handle correctly). This works much better than score-and-slip, it's faster, and it's far less messy; your handle looks like you just pushed it there with your thumb. No slip-slop cleanup!

Now, some other tips to help with handles. At the top of this post, you'll notice pink stuff on the handle attachment points and the "sides" of the handle. That's a thick wax resist called Wax-On. For some reason, if you paint wax on any attachment seams when attaching handles and sprigs to pieces, those seams are much less likely to crack -- even when fast-dried. I don't know why this works, but it definitely does.

The other problem with handles is that they split while drying. This happens because the handle, which made of clay that's exposed on all four sides, dries faster than the body of the mug, where each band of clay is exposed on only two sides. So, if you paint two sides of each handle with wax resist, the handle will dry at the same rate as the mug it's attached to ... and not crack.

For my final tip, lemme encourage all you junior potters out there to learn to pull handles from the mug. Yes, it's hard to learn and you'll ruin a few mugs trying. But once you're good at it, the handles look better and are much faster to make than handles you make seperately, then attach.

Happy mug-making, all!

Since custom "logoware" is a significant part of my pottery business, I'm quite used to making custom "sprigs" so that I can stick people's logos, names, or other designs on thrown pottery. For a long time I've done this one of two ways: either I order a custom rubber stamp online and press it into a slab, or I sculpt a design out of clay and then cast it in plaster.

But now I have a new method, using 3D printing and silicone. Keep reading and I'll detail how you can use it too.

Why would I want to do something new? Well, both older methods have problems. The custom rubber stamps are expensive and slow to order, and never make a deep enough impression. Plaster is really annoying and time-intensive to cast with. And both methods involve some extra steps I'd rather not take: rolling slabs for the stamp, or prying the sprig out of the plaster before attaching (and possibly damaging it in the process).

So, let me show you the new method.

First, you want to design a 3D model on your computer that can be printed out. For folks just getting started, I recommend TinkerCAD, the free, simple 3D design program from AutoDesk. It's set up for this; for example, if you import a 2D logo or text into it, TinkerCAD automatically turns it into a 3D shape, ready for you to manipulate into a stamp.

Now, if you have your own 3D printer, you can then print this design yourself. If you don't, though -- and I don't recommend buying one unless you're ready for a new, time-consuming hobby -- you can get it printed via PrintAThing, a brokerage that contracts folks with 3D printers in your region to print and ship it to you cheaply and usually quickly.

You can also mold things you sculpted yourself, of course. I do a little of both, 3D printing logos and text, and sculpting things like slugs. Place your objects to be molded on a smooth, flat surface, far enough apart that you can cast each one separately. Like plaster molds, you want to avoid having too many undercuts -- but unlike plaster, you can have some, which is another advantage here. The flexible silicone can be pulled off of small undercuts.

Now, on to make the silicone mold(s). This will require 100% silicone caulk (and a caulking gun), some liquid food coloring (not gel), a whole box of corn starch, some disposable containers, and rubber gloves (you need these). You're making proto-putty per the video. Watch that for the method, which is to mix a couple teaspoons of food coloring into the silicone, then mix the sticky gel with the cornstarch until you can handle it.

There's another method of making moldable silicone using dish soap, but I haven't tried it. Lemme know if you do.

Then you press the moldable silicone, like clay, onto the objects you're casting. You need to move fast, because you have 10 minutes from the time you add the food coloring to work with it. You also have the tricky task of making the molds thick enough to be sturdy, but thin enough to be flexible. This is relatively easy with flat shapes like a logo sprig, but can be challenging with complex shapes like the slugs.

Then, you wait for it to set and harden. You can pry the objects out of the molds after only about an hour, which is useful to see if you got a big air bubble or similar and need to re-cast one. You should wait at least 12 hours before using any of the molds for clay, though. Once the molds are hard, you can also trim them with a serrated knife.

Now you come to the main drawback of using silicone: clay sticks to it. This means you need to powder the molds generously with more cornstarch before each use to get the clay to release. This can cause "stippling" on the molded design, so I'm looking at trying out some actual mold release agents instead, but for now I know cornstarch works.

After this, you should rough your pottery and the bottom of the molded clay with a toothbrush and some deflocculant like magic water, and then you stick the sprig directly on the pottery, bending the mold around the curve of the pot. That's the big advantage to silicone molds; you stick sprigs directly on your pots, eliminating prying & drying, and getting a better attachment & seal onto the pot in the bargain. It'll take you a few trials to get how to press the mold onto the pot (as well as keeping it oriented), so have some test pots to play with.

This works particularly well with decorations that need to be curved, like my infamous banana slugs: you're attaching them while the clay is wet and workable, so no cracking, and you can even pry up the edges so that undercuts (like the slug's mantle) come clear.

All of this was very easy to get started doing, and has completely replaced my old ways of doing sprigs. I hope it helps you too.

Oh, and if you want to buy one of those slug mugs, meet me at The OPA Holiday Sale this November 30th.

When I was learning to throw, how I was taught to attach handles and other pieces of clay to each other was:

1. score heavily with a fork (both pieces)
2. add thick slip to both pieces
3. score the slip
4. push them together until slip squished out
5. clean off the excess
6. add a thin coil into the crack
7. blend together

I did the above for 20 years and more pieces than I want to count. Many — probably most — students are still taught this method. And it's completely wrong.

Students should be taught the modern way to stick clay together. Not only is it easier, it's more effective and it looks better:

1. Dip a toothbrush in Magic Water.
2. Rough up both sides with the toothbrush, dipping it again as necessary so that both sides are wet and rough. Ideally, the brush strokes should go in the same direction for both pieces.
3. Gently press the two sides together, wiggling them until they "stick".
4. Smooth out the joint.

"But what's Magic Water?" you ask. "And won't the handles pop off? And what's the green stuff in the picture? And what am I supposed to do with this fork now?"

Magic Water is both a deflocculant (a substance which changes the binding properties of clay) and a flux (one which makes clay melt). As a result, it allows to pieces of clay to bind together better when wet, and it helps them stay together when fired. Here's a recipe, originally developed by Lana Wilson. It's easy and cheap to make if you have access to a ceramics supply house:

• 1 gallon purified water
• 3 Tbs liquid Sodium Silicate
• 3 grams Soda Ash

When I switched from slip to Magic Water, I decided to do an experiment. I made 18 mugs, half using slip-and-score, half with Magic Water. Two of the slip-and-score mugs had handle separation issues (one broke off entirely). None of the Magic Water mugs had problems.

Now, if you're using magic water and your handles are popping off anyway, you're probably not controlling drying properly. Sometimes handles pop off because they weren't stuck on well, but most of the time they come off (or break in half) because they were allowed to dry at a different rate from the cup. Just avoid these three pitfalls:

• sticking a wet handle on a dry mug body
• letting the mug dry too fast
• letting the handle dry faster than the mug

For the first, you'll lower your loss rate tremendously by attaching the handle before the cup is leather-hard. This does make it difficult to trim the mug, which is why most of my handled mugs have flat instead of footed bottoms. But the closer you can get the handle and the mug to the same level of wetness when combined, the fewer problems you'll have. The second problem can be avoided with a wetbox or some dry-cleaner plastic.

For the third problem, well, that's where the green stuff comes in. Handles tend to dry faster than mug bodies because they are thin and get air from all sides. If they are allowed to dry as fast as they want, then they will crack or pop off because the handle will become shorter than the clay it's attached to. That green stuff is AFTOSA wax, a thick formadehyde-soluable wax which will stick even to leather-hard clay. By painting the thin edges of the handle, you slow down the handle's drying rate to match that of the mug. I've also found that waxing the joints makes cracking at the joints less likely, although I'm not completely sure why.

So, there you go: a newer, better-looking, easier, and more effective way to attach your handles to mugs. Now go and make some mugs!

As for the fork, well, maybe a salad?