Making —Ultramarine watercolour paint

Ingredients

Current procedure — last updated 26. August 2022

  1. Mix the watercolour paste
    1. Measure out the powdered pigment and place it in mixing crucible.
    2. Then pour the medium on top of it.
    3. Start dispersing, using a dispersion disc in a drill press.
    4. Cover the bowl while dispersing to limit the dust.
  2. Mill the paste
    1. Set both rollers to 6mil.
    2. Prepare a large bowl and a hopper to use. Find a stand to raise up the bowl to catch the paint to reduce splashing.
    3. Use a nail brush and water to clean the rollers at the end of the first runs.
    4. Put through the mill 8 times.
    5. Test for grind at the end of run #4, #6, and #8.
    6. At the start of run #7, add one drop of clove oil for 250ml of total medium (100ml mix = 4-5 drops) Add the oil to the paste on the slow rollers, rather than in a bowl on in the hopper.
  3. Package into pans
    1. Arrange the 350ish empty 2ml half-pans into rows on a cookie sheet
    2. Fill the pans to the top with a dispenser set to 2.5ml
    3. Allow to dry, and then top off
    4. Allow to dry, and then package into wax paper bags

Drapak’s manufacturing notes

26. August 2022 - 150g pigment: 1000ml medium
Pb29: 150 grams × $0.065/g = $9.73
Watercolour medium 1000ml × $4.43/1000ml = $24.43
Number of pans filled 377 pans equivalent × $0.08/pan Cost of pans = $30.16
Total for materials = $64.32 Material cost/pan = $0.171
Time to mix 0 minutes
Time for pre-dispersion 30 minutes
Time to mill 140 minutes
Time to dispense 60 minutes
Total time 230 minutes
Final grind size 10-20µm
Time spent per pan 0.61 minutes × labour rate $0.445/min= $0.272
Total cost/pan = $0.44

Wow! I am starting to get the time down better! Yay!

I did 10 runs of the ultramarine, and I added the clove oil during run #7. This helped act as an emulsifier, keeping some of the particles in suspension during dispensing.

I did have another small spill with the funnel not working quite right, but I lost very little paint. However, the funnel did leak a little during dispensing. The nozzle was not threaded on fully, which caused the funnel to leak ultramarine all over the counter, which, luckily I had covered in an old towel.

Next time, make absolutely sure the nozzle is threaded properly! The nozzle seems to have a burr on it that causes a false cross thread. Boo!

The pigment itself was shockingly well behaved. The only issue was a bit of granularity, but from my experience, that is just the nature of ultramarine. Milling the pigment 10 times certainly helped though.

As the pigment dries, I would say that the paint seems to be a little pigment poor. I think that this may be because it is an inorganic pigment. When I top it off, I will add much more pigment to the mix.