Casein Binder Wehlte (Borax Casein), 1 l

Borax casein, recipe according to Kurt Wehlte

Processing

Step 1:
You will need:

• 40 g lactic acid casein powder, cold-swollen for approx. 12 hours in 125 ml water
• 16 g borax, crystalline dissolved in 125 ml water, as hot as possible
• A large porcelain rubbing bowl with pestle, an enamelled bowl or a plastic one
• A stirring wood

Step 2:
The porcelain bowl in which the soaking of the casein powder has already been carried out is covered right from the start with a folded, thick, soft, strongly moistened cloth, so that initially no casein grains dry on the edge and remain excluded from the swelling process, and that furthermore a skin formation on the finished casein glue is prevented until it is used or filled into a sealed container.

Step 3:
Stir the hot borax solution into the gritty casein slurry, stir two or three times after a few minutes and leave covered.

Step 4:
In the course of 1 to 2 hours, no more individual casein grains are visible in the viscous, yellowish cloudy mass, a sign that the digestion process is finished. Nevertheless, you can leave the digested mass in this state for up to one day, whereby the finished casein glue becomes even more creamy.

Step 5:
If you want to store the casein glue for several days or even a few weeks, it needs to be preserved. But it is much better to prepare only small quantities of casein glue fresh at a time and not to keep it for longer.

Step 6:
For use as paint glue, dilute this quantity of glue further with water to the total volume of 1 litre, so that the concentration of casein in the paint solution becomes 4 %. With one litre of casein paint you can brush about 10 m² on a non-absorbent, smooth surface.