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.

Lots of potters by now are familiar with the Ball Opener tool, popularized by Tom Whitaker. Speedball even has a version for sale, although I'd argue that it's inferior to one you make yourself from PVC. I use ball openers when I make matched sets, because making sure that the bottoms of all pieces are identical thickness makes it much easier to make them all identical.

After a few years of making plain glued PVC ball openers, I started thinking about how I could improve the device. Particularly, how could I incorporate 3D printed elements to make it better, and maybe make the thickness dynamically adjustable? I did a bunch of experimentation, and a bunch of trials, and have come up with a new design that I call "Ball Opener Mark 2". For any of you with a 3D printer and assembly skills, I think you'll find it a worthwhile improvement over the individual design.

Building The Mark 2

To make the Ball Opener Mark 2, you will need:

• 2-3ft of 1/2" thick wall PVC pipe
• A 4-way PVC junction and two elbows
• 3ft of 1/2" wooden dowel rod
• A cutoff, table, or band saw for cutting that pipe and dowel
• A power drill and 1/8" bit
• One 2.5" piece of 3mm brass rod
• PVC "glue"
• Superglue gel or E6000 glue
• All of the 3D printed elements included in this set
• A toothpick

First, you'll want to print all the 3D printed items for the Ball Opener. There's a bunch of them, so get started now. PLA filament is fine. See the notes in the Thingiverse entry on how to print them.

Cut the PVC pipe into two pieces 4.5" long, two pieces 3.5" long, and one piece 3" long. Fit the two 3.5" pieces on opposite sides of the 4-way junction, and cement them in with PVC glue. Fit the elbows onto the ends of those pieces, and glue them in, making sure that they are exactly parallel to one of the unused openings of the 4-way junction. Fit the two 4.5" pieces into the elbows and glue. Finally, glue the 3" piece in the 4-way opening on the same side as the other two pieces, forming an "M" out of PVC. Allow all the PVC glue to set, around 1 hour.

While the PVC glue is setting, cut three 6" pieces from the dowel rod. Attach each of the 3D printed ball opener Opener Tips to one of the dowel rods. Glue these in with the superglue/E6000. Bend down one end of the brass rod, about 1/2".

Once the PVC glue has set, glue in the rest of the 3D printed parts. The two PVC Plugs go on the two outer legs of the M; these are to keep the PVC from getting worn down by the friction of the wheel too fast. The Top Plug goes in the top of the 4-way junction. As you glue this in, make sure that the slot on top is exactly parallel with the PVC cross pieces. Now, time to wait for all that glue to dry, at least a couple hours.

Once that's all set, fit each dowel into place by inserting it up through the center of the M. Mark the dowel rod where the slot in the Top Plug is. Take it back out and drill a hole through it at that mark. Repeat with the two other dowels. Label each dowel with its gauge thickness with a sharpie.

Your Mark 2 is now manufactured. You might want to wait overnight for all glue to be completely set.

Using the Mark 2

To use your new tool, push one of the Opener Tips with its dowel through the center of the M, and then anchor it using the brass rod. You can change the height by switching which of the Opener Tips you use, and you can (and should) 3D print more with different thicknesses. I have named the Opener Tips with the distance from the wheelhead, which becomes the thickness of the clay bottom. These distances are not exact, particularly given that none of us is precision-cutting our PVC.

Now, you can use it like a regular ball-opener per Tom's video.

However, the Mark 2 comes with a bonus feature: a Width Gauge. I designed this because, in order to make matching pieces, I also wanted to make sure to open each hole the exact same amount. The way you use it is this: before locking in the dowel with the brass rod, you slide the Width Gauge over the top of the 4-Way, ringing the Top End, with the slots matching up. Then lock everything in place with the brass rod. Put a toothpick in the little hole, pointing down. When you throw, follow the toothpick with your eye to see if you've opened the hole the right amount.

The example width gauge in my 3D print set is for a hole 95mm wide. You will, of course, want to make ones a variety of sizes. Note that the flat bar needs to be 27mm shorter than the desired hole width, because of the width of the ball opener itself. Eventually I'll create an OpenSCAD template for generating them.

On to the Next

I hope you enjoy building and customizing your own Mark 2 Ball Opener.

For me: it's been a learning experience, and I already know how I want to build the Mark 3.

Q&A

Why use PVC plus 3D prints instead of 3D printing the whole thing?

Extruded filament plastic, regardless of filament type, doesn't have anywhere near the strength of commercially formed PVC pipe. A fully 3D printed model would break in use. Another artist is experimenting with resin printing, and I'll update this based on what they find out.

Why not just make a bunch of all-PVC standard ball openers at different heights?

Because that would have been a lot less fun, and take up more space. Also, this design has some other advantages like the width gauge.

Is it important that all my pipe and wood cuts are exactly perpendicular and smooth?

Yes.

Why do you mix American and metric measurements?

Sorry, I live in the USA, that's how things are here. If you're in another country and want to make an all-metric one, you'll need to redo the measurements yourself.

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.

For the recent Cake Night Cookie Fight event, I made a "ReplicaSet" of pressed cookies decorated with the Kubernetes wheel. While I only placed 2nd thanks to Rin's amazing prowess with cake, they were super-tasty and I figured folks would want the recipe anyway.

The first step is to make yourself a cookie press. I made a design using TinkerCAD and 3D printed it the day before. The mold comes in two pieces, you superglue the handle to the press. And then you need to spray the inside of the mold with food grade silicone spray (or it will not release your pressed cookies) and leave it overnight to dry.

After that, you can make a fairly simple shortbread and press it into the molds. To make it more exciting -- and to go better with bourbon -- I made a garam masala seasoned shortbread.

garam masala shortbread

Dough:

• 1 cup (2 sticks) salted butter, softened
• 1/2 cup dark brown sugar
• 1 1/2 tsp garam masala
• 2 1/4 cups AP flour
• 2 to 6 tsp cold water

Sugar coating:

• 1/4 cup white granulated sugar
• 1 1/2 tsp garam masala

Colored icing:

• 3 tsp milk
• 2 Tbs, or more, powdered sugar
• 3 drops liquid blue food coloring

First, two hours before making the cookies, take the butter out of the fridge so that it can soften completely.

Cut the butter into chunks, and cream it in a mixer on low, or with a spatula and a lot of elbow grease. When completely smooshed, add the brown sugar. Cream until the sugar completely dissolves into the butter.

Sift the flour and the garam masala together, and then add to the butter, one third at a time, stopping when no more dry flour is visible. Now, judge how crumbly it is; it should be somewhat crumbly, but easily hold together if you pinch a small amount of it. If it's doing fairly well, add just 2 tsp water and mix it one last time. If it seems dry and won't hold, add more water, all the way up to 2 Tbs, if required. You don't want it sticky though, you want it to just barely hold together.

Cover and place in the fridge for 25 to 45 minutes. Do not press it into a ball or anything; you want a bowl full of loose crumbles of dough. You also do not want to leave it overnight; if you need to leave it for more than 45min, then you'll want to let it warm on the counter for a bit before using.

While it's in there, put the white sugar and the second 1.5 tsp of garam masala into a small flat bowl and mix them together. Then, make the icing by putting the milk in a small bowl, and mixing in enough sifted powdered sugar until it has a thick, gluey texture ... probably around 2Tbs. Add the 3 drops of food coloring and mix until fully blended. Finally, put a little flour in another small flat bowl for coating the cookie press.

Turn the oven on to 350F to heat, and arrange the oven racks so that you can put two cookie sheets in.

Take the dough out of the fridge, and start pressing cookies. Line two baking sheets with parchment or silicone. Flour the cookie press. Take around 1.5 Tbs of dough out of the bowl and roll it into a ball; it should be between 1" and 1.25" in diameter. Drop the ball into the granulated sugar mixture, and flatten it into a small disk, turning it so that it's coated on all sides.

Place the small disk of dough on the corner of the cookie sheet, and press the cookie press down on it. Carefully lift it off, starting from one side, and be prepared to pry the cookie out gently if required. Repeat this until the cookie sheet is full; this will take a fair while.

When one cookie sheet is full, put it in the oven and set a timer for 6 minutes. Start on the second cookie sheet.

After it's been baking for 6 minutes, turn the sheet around for even cooking. Set a timer for 4 more minutes. After that time, check the cookies. If they are showing a thin rim of dark brown on the bottom edges, they're done, take them out. Otherwise bake them for 1-3 minutes longer, until they do.

Place cookies on a rack to cool. Put the 2nd sheet of cookies in the oven, and repeat.

After 20 minutes or so, when all cookies are cool, paint the raised design with the blue icing using a small paintbrush. The icing will take another 15 minutes to dry. Serve, or put in a sealed container and store at room temperature. Makes around 32 cookies.

One of the reasons I bought a 3D printer was to start printing my own clay extruder dies, for a variety of purposes. I've made my own extruder dies before in my father-in-law's metal shop, but I'm not that good at milling and as a result the shapes I can make are quite limited. With a 3D printer I can make any plate I can reasonably design.

So, when I realized that I was going to need a lot more test tiles to create a reliable seashell pink in cone 10 reduction glaze, it became time to print some plates. Two plates -- one for the test tiles, and one for the test tile holder. Why I need a holder will become a lot clearer once you see the design. But first, I needed to design the plates.

I have a TA Metalworks extruder. It's a similar design to the popular North Star Extruder (and my plate designs will probably work for both). This model of extruder has a long square tube, and normally the extruder die is clamped between this and a square retaining bracket below.

There are two problems with this design. First, you tend to get a lot of clay squishing out the sides between the end of the tube and the die. More importantly, though, this means putting a lot of clamp pressure on the die, which would force me to make my 3D printed plates with 100% fill to make them sturdy enough, and even so the PLA might crack. If I made a die that fit inside the extruder tube, instead, I wouldn't be clamping the die between two pieces of metal, and I could then use a gasket which would limit clay squeeze-out.

So, I first made a metal retaining plate with a square hole that was 1/4" smaller than the tube. I then screwed this together with the retaining bracket for the extruder. You could also do this by welding 1/4" metal plates to the inside of the retaining bracket if you wanted, or you could use heavy wood instead of sheet metal. I put some gasket rubber over the top of this to make for a good seal.

Next I carefully measured the inside of the extruder tube and designed a blank extruder die that exactly fit, as tightly as possible. I made it 1cm thick so that it would be strong enough, and then went to work on my designs, using TinkerCAD.

Designing the die for the test tile was easy enough; it's an 8cm long flat tile, with two raised semicircular bumps in order to check glaze texture breaking and pooling. This is a shape I've been using for ages, and this 3D printed plate replaced a rougher metal plate I made on the milling machine.

I printed my dies using Crealty Silky PLA, with 50% infill printed in a gyroid pattern for strength. So far, I have yet to have a die crack, even when I used clay that was a little too hard. The main funny thing about 3D printed dies is something you'll notice when you clean them: they float!

You'll notice, though, that my tiles are not self-supporting. That's on purpose, because after I'm done firing them I like to screw them onto a board for display and quick reference. But it does mean I need a holder to keep them standing upright in the kiln.

So, I created this extruder plate for holding test tiles upright in neat rows in the kiln. Theoretically you can have three rows of tiles in it, but because none of them can touch it's more often two.

Time to do some extruding! I assembled everything and pushed some Tacoma MAC10 white stoneware through. Works great! And notice -- no clay squeezing out of the sides.

I then took the long strips of test tile, cut them into individual tiles, and added holes in the bottom for eventual screws.

Turning them over, I use a numbering stamp to number each of them so I can track my tests.

Here's the full deal, awaiting bisque. You can see how the test tiles will go into the kiln once I'm ready to use them for glazes.

My 3D designs are all up on Thingiverse if you have a TA or Northstar extruder yourself and want to try out making your own dies. The software I use is TinkerCAD and OpenSCAD for designs, and Prusa Slicer for slicing. I do my printing on a Creality Ender 3 Pro with a WhamBam print surface.

Given that I live in Oregon, lots of folks I know have been making masks with bias-tape ties. These have the advantage that they don't require elastic (still in short supply), aren't head-size specific, wash better, and are more secure for long use.

However, the ties are super-awkward to tie behind your head, particularly if you have long hair.

Since I have long hair, I decided to create a 3D printable design for a "hook clasp" that could be easily threaded onto bias tape ties and easily fastened, and even tightened. It took me a bunch of tries, but I did it.

Please make use of my hook clasp design on Thingiverse, and 3D print some of your own. If you have a 3D printer, consider printing several dozen (it takes 4 per mask) and sharing them out with your friends who have masks that tie. The easier and more comfortable we can make wearing masks, the more people who will wear them.