Diff: CadmiumDendrites

 The zinc plating on the steel components of Hammond organs sometimes can grow metallic fur or ''dendrites''. I have no idea what the actual growth mechanism is (if you know, please enlighten us!). Heat and humidity can tend to speed the growth of dendrites. 

  

 Even scientist don't know the actual reasons for dendrite growth. The gravity induced convection makes it impossible to track the dendrite growth. Therefore they made an experiment, that flew with the space shuttle: 

 Isothermal Dendritic Growth Experiment (IDGE). One thing is known for sure: the solified zinc surface shows the dendrite structure already. And the fresh zinc surface is chemically active. If humidity is high, a zinc solute can occur, which leads to the growth. A way out of this is to plate the surfaces with chrome to passify the zinc. A simple lacquer layer does the same.