26 November 2019
17. I wanted to try growing crystals from Copper Sulphate (I was already using this as my electroforming solution). For this, I dipped a wooden stick wrapped with copper (previously used as anode) in Copper Sulphate + water solution
After 24 hours
18. Next I tried the same (17) with vinegar instead of water.
After 24 hours
19. Copper Strip (previously used as anode) wrapped on wooden stirring stick dipped in Pink Salt + White Vinegar
After 24 hours 
After 24 hours
20. Alternating Copper and brass strips wound on wooden stick dipped in White Salt + Vinegar
After 24 hours
21. Brass Strip wound around wooden stick dipped in White salt + Vinegar
After 24 hours
Observations:
From 19. and 4. I concluded that the blue crystals were due to slow corrosion of copper.
Wood allowed absorption at just the right speed to give the crystals their fern-like’shape.
19. also suggests that fresh copper (with top coat removed during electroplating) might have caused the faster corrosion reaction, giving significant crystallization over a shorted period of time (compared with 4. and original paintbrush accident).
Brass was not as successful in producing crystals ( I need to check what metal my original paintbrush is composed of).
Copper sulphate in water and vinegar started to produce crystals slowly, over 24 hours.
Precedents to look at:
Lukas Wegwerth: Crystals grown along unglazed areas in ceramic objects
design factory 