Ingredients
- 150g dry powdered pigment Ultramarine blue (red shade) Pb29 from Kama Pigments
- 1000ml watercolour medium
- PPE: mask, gloves, and apron
- A measuring cup
- A digital scale
- A stainless steel bowl (1500ml+)
- A stainless steel hopper (1500ml+)
- 28oz Blender Ball protein shake mixer
- Drill press with dispersion disc
- A three roll mill
- Small watercolour half-pans
Current procedure — last updated 26. August 2022
-
Mix the watercolour paste
- Measure out the powdered pigment and place it in mixing crucible.
- Then pour the medium on top of it.
- Start dispersing, using a dispersion disc in a drill press.
- Cover the bowl while dispersing to limit the dust.
-
Mill the paste
- Set both rollers to 6mil.
- Prepare a large bowl and a hopper to use. Find a stand to raise up the bowl to catch the paint to reduce splashing.
- Use a nail brush and water to clean the rollers at the end of the first runs.
- Put through the mill 8 times.
- Test for grind at the end of run #4, #6, and #8.
- 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.
-
Package into pans
- Arrange the 350ish empty 2ml half-pans into rows on a cookie sheet
- Fill the pans to the top with a dispenser set to 2.5ml
- Allow to dry, and then top off
- Allow to dry, and then package into wax paper bags
Drapak’s manufacturing notes
26. August 2023 - 80g pigment: 1000ml medium
| Pb29: | 80 grams | × $0.065/g = | $5.20 |
|---|---|---|---|
| Watercolour medium | 500ml | × $25.41/1000ml = | $12.71 |
| Number of pans filled | 480 pans equivalent × $0.08/pan | Cost of new pans = | $0 |
| Total for materials = | $17.91 | Material cost/pan = | $0.11 |
| Time to mix | 20 minutes | ||
| Time for pre-dispersion | 10 minutes | ||
| Time to mill | 75 minutes | ||
| Time to dispense | 60 minutes | ||
| Total time | 165 minutes | ||
| Final grind size | 12.5µm | ||
| Time spent per pan | 1.03 minutes | × labour rate $0.48/min= | $0.50 |
| Total cost/pan = | $0.61 |
This was tricky. I would say that this proves that small batches are not that great an idea. The labour in this one ended up making a big difference, despite the fact that the pigment is reasonably priced.
The pigment could still use enrichment: perhaps trying a 180g pigment mix would be worth it next time.
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.