How to cast beads using DIY casein plastic?

Question

I'm experimenting with DIY casein-based plastics, using powdered milk. There are lots of references to casein plastic originally being used mostly for buttons & beads, but no actual instructions for how to form beads.

My problem is not how to make the stuff, it's how to make more than one bead at a time including holes, as is done with some glass and clay beads. Casein plastic made with an organic acid does start out the same as paneer - Indian "cottage cheese"

Answer 1

I actually did this six months ago, and the shape that I cast is still solid, virtually indestructible and mold-free, so I am speaking from experience here.

The instructions I wrote down here for making milk paint are very similar, but with a few notable differences. It is very important that you work in a hygienic and sterile environment, which means really taking care not to introduce microorganisms and fungi.

Casein is a milk-based product that you can make by warming whole milk in a copper saucepan and adding about 5 drops of lemon juice per liter. Whisk the milk vigorously, making sure to whisk the copper saucepan. You don’t have to get it boiling hot, but it mustn’t be cold. You will see clumps forming, and then remove it from the heat. Pour the entirety through a fine-meshed strainer and reserve the watery part (the whey).

Because ultimately we want to remove all of the water, put the clumps in a clean nylon stocking and squeeze out all of the moisture that is left. Then remove the casein and put it on a baking sheet that is lined with waxed paper / baking paper. You will find that the casein is a little crumbly and tends to fall apart, but if you squeeze it between your fingers it will retain its shape.

Then you force the casein into a beadmaking form like this and bake it at about 150 degrees Celsius for three to four hours.

NOTES

You may wonder why the copper saucepan. That is because by whisking the milk in it, you are adding copper ions to the casein, which act as a natural antibacterial and antifungal agent.

You can also add other materials like pigment or fillers to the casein - and although I haven’t tried it, I expect that using Marble Dust (available at better art supply stores) would strengthen the final product, as would adding mica flakes.

Answer 2

This is an old question but from the number of views, other people have a similar interest. Nothingismagick's answer addresses how to make multiple beads. I'll address two holes in the discussion.

1. For molding small parts like beads, you don't want to start with crude cottage cheese. That's the result of the first step in the process; the material needs additional refinement. The cottage cheese chunks result from impurities left in the casein. These can be removed with subsequent steps that redissolve the casein and reprecipitate it. The result is a uniform putty that is moldable. See https://www.youtube.com/watch?v=BnXGZKCrktE.

2. The other hole in the discussion is the holes. If you are using a mold tray that has a series of bead molds nicely aligned, this is a solution you can reuse. It takes a little precision work to make, though. The holes can be molded into the beads.

   Use something like paint stirrers to make a frame around the mold to which you fasten a paint stirrer centered over each row of bead molds. This is to keep everything aligned. Take very accurate measurements of the location and spacing of the center of the hole for each bead, and transfer this to the paint stirrers. You may be able to do this by taping a piece of paper over the top or bottom of the mold and doing a "pencil rubbing". That will be easier to measure; you may even be able to mark the wood through it with pins.

   Use large, long straight pins with a diameter a little larger than the filament you will use to string the beads. Use a drill press or equivalent to drill tight-fitting holes for the pins in the paint stirrers at the marked locations, ensuring the holes are perpendicular. Drill the same size holes in the center of the bottom of each bead mold. Push the pins through the paint stirrers far enough so they poke through the bottom of the mold.

   Remove the hole maker from the mold. Press the casein into the molds to fill them. Lubricate the pins with a thin coat of oil or soap. Then carefully align the hole maker and press it into place until the pins exit the bottom of the mold. Leave it in place until the beads are dry. When you remove it, the beads will have holes.

   You could experiment with a batch of beads where you insert the pins and then immediately remove them. That may compress the casein and the holes may partially close when you remove the pins. The beads may also shrink a little as they dry, which would reduce the hole diameter. If removing the pins leaves too small a hole when the beads are dry, you could drill or ream them out (or discard them). If the holes are reliably smaller by a particular amount, you could start with bigger pins to end up with the hole size you need.

Answer 3

With a quick stroke of the keyboard, The Great Google returned many results for "casting with casein resin" including a resource that is a favorite of mine, Instructables.

Take a look at this Instructables page which describes mixing milk and vinegar in a saucepan, which is heated to form the mess or mass of "plastic" material. Additional hints are provided, including the suggestion to have your mold ready to receive the material.

The comments posted by other Instructables members suggest that the creator has made a version of cottage cheese, while another references the typical (PVA) wood glue. Yet another post offers a slightly different method of processing with the addition of some ordinary bicarbonate of soda.

As with all Instructables, the entry on the above page has been improved by the addition of a photo of a cat.

Obviously this is not the cat photo.