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Tom Lauerman
Artist, Teacher, Dad
Artist, Teacher, Dad


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Just thought I'd share two sides of an object I'm trying to make with a wave pattern on its surface. Same chunky clay and thick nozzle (3mm). Been working recently with printed, then assembled parts. Takes a lot of time, but enjoying the process. (If I am posting too much shout at me! - trying to keep a little momentum in these summer months)
2 Photos - View album

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I am posting this article as appreciation of everyone in this forum. +Farhad Manjoo articulates something I've felt for some time but couldn't put my finger on. Forums like this one, where we help each other make things, are a throwback to the early promise of the web. I hope others here in our network of hobbyists (and professionals) collaborating on 3D printing in clay feel the same enthusiasm.

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Took a little break from high resolution printing to try and print some really stiff and groggy clay. This clay had a specific gravity of 2, the stiffiest clay I've printed with thus far. It was printed with a 3mm nozzle at 1.5mm layers. In close up image the coarseness of the clay really shows. The auger speed was high, so you can see some patterning from over-rotation, which was not intentional. Object is 300mm tall.
3 Photos - View album

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Some recent printed objects-in-progress in a range of clays. Mostly these have been bisque fired but they have not yet been glazed. I have a terrible time deciding on surface colors/textures. Any suggestions?

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Playing around with higher resolution (and agonizingly long print times). This is a 0.8mm nozzle making 0.4mm layers with 35% infill. I dug this clay out of my backyard (and sifted it through screens to remove debris). This object will (hopefully) be 120mm (3.7") tall when complete (in 5 or so hours).

Hello Everyone,

I thought I'd get a little more specific about clay density in an effort to discuss consistency for printing without relying on descriptive terms ("firm", "soft", "toothpaste") and instead to consider something more quantitative.

So here is my best attempt at measuring the specific gravity of the clay I'm using. I'm not great at this kind of thing, if anyone sees errors in my process please let me know!

Here goes:
The clay tubes I use for my printer have a 50.8mm (2") interior diameter, and are 305mm (12") tall. By my calculation that is a volume of 617777 cubic mm, which is equal to 617.7 ml. Therefore, water filling the tube would weigh 617.7g.

I loaded the tube with wedged clay using a wall mounted extruder. There were no visible air gaps in the tube after loading. The fully loaded tube weighs 1401g. The tube itself weighs 187g, so the weight of the clay in the tube is 1217g.

1217g is 197% of 617g (the volume if filled with water)so therefore:

The specific gravity of this particular clay is (I believe) 1.97.

I then measured another batch I had been working with, it was similar but softer - it's specific gravity was 1.89

By comparison the specific gravity I am accustomed to using for casting slip is usually between 1.72 and 1.80.

For additional comparison, I borrowed some soft wheelthrowing stoneware clay from our classroom and it had a specific gravity of 1.94.

Then I tested a firm handbuilding earthenware clay I was sure would have a much higher specific gravity, it turned out to be 2.

However, the water content is only one part of the story. The plasticity (or pliability or stickiness) of the clay plays a big role in how desperately the clay clings to its container. When I add a great deal of chamotte (or grog) to the clay body it very much reduces the plasticity of the clay and makes it more possible to push firmer clay through a nozzle (assuming the particle sizes are not so large to block the nozzle).

Anyhow, I would certainly welcome any one else's efforts in this vein, if you are willing to take the time to weigh your clay and determine its specific gravity. I really wish I had done this with Jonathan's clay when he was here visiting, as I would love to quantify the degree to which it was softer.

Because I have to fill these tubes to use my printer and I have a good quality scale in the same room, I'm just going to make a habit of weighing each batch to get a bigger bunch of data on the topic.

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. . . it's been a little while since I posted an image of my printer design, so here it is after a few recent changes and additions. Still evolving . . .

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. . . my first clay print (November 2015) and a detail of my most recent. Revisiting this "tumbling blocks" object.

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Since we have been discussing stepper motors a lot I made a quick comparison chart between several of the NEMA 17 and 23 motors used by some of us on this forum.

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This poll seeks to explore our forum's geographic diversity. Google limits polls to 5 categories, so Antarctica has been excluded while Asia/Australia/Oceania are gathered together here. Russia and Turkey span two continents but Google limits users to 1 choice in a poll. Many thanks in advance to anyone interested in participating!
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Asia + Australia/Oceania
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North America
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South America
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