Tuesday, April 12, 2011

Instructional Video

Slip casting is a type of ceramic processing.  It is also the method I'm using to create bulletproof mugs.  So I thought it would be good idea to make a video on how to make a 2 piece plaster mold.  It goes by a little quick so if you have any question about what happened during the process feel free to write it in the comment so I can answer them.  I hope you enjoy the video.


  1. Nice demonstration! I just have a few questions:

    Can you tell us about how slip casting works after the mold is made? It has to do with building the object in layers, right?

    Does the mug actually come out bulletproof?

    Which ceramic do you use to make the mug bulletproof?

    Are stores selling bulletproof mugs?

  2. Great question I hope these response answer them.

    Well once the mold is dry you separate the two halves of the mold and remove the initial object. After that you bind the two halves of the mold together with something like bungee cord and pour in your slip up to the top. The mold jobs is to pull out the moisture in the slip. As the moisture leaves the walls of the mug build up with the ceramic material and once you've reached your desired wall thickness you dump the rest of the slip out.

    When you remove the mug from the mold it is in a fragile state called the green state. In the state we clean up the mug and remove any defects from the surface. Then we fire the mug at high temperatures. This hardens the mug turning it bulletproof.

    There are many ceramic materials which can be used to make a mug, however we are using alumina and zirconia.

    To be honest I don't know if they are selling bulletproof mugs. My guess is no because the cost to construct one of these is around $100. So I don't think there a huge market for this stuff right now.

  3. So is it the type of ceramic that makes it bulletproof, or the process used to cast it?

  4. It's actually combination of both. Certain ceramics have higher toughness values than others. Toughness represents the amount of energy a material can absorb before breaking. So the more energy it can absorb the better it is.

    Now were the processing come in is pores and defect act as stress concentrators. These concentrators can cause a material to fail prematurely at lower stresses. Now slip casting does not offer maximum densification which is why it is not traditionally used in armor. It does allow you make more complex shapes which is why it is used in mug construction. For actually construction of armor plates the process used is called hot isostatic pressing.

  5. I LOVE THIS VIDEO!!!! It's so accurate.


  6. This goes by a little fast, and I think we would like to see the next step. But this is a great way to illustrate the process.

  7. Unfortunately there is only so much I can show about this process in 2 minutes. The whole process actually take about 2 days to complete.