Think this deserves a topic on its own.
Had a binge at anodising for a few years but couldnt get the colouring right. No way of knowing until job completed and sealed.
Many a time had loss of contact - creates an oxide build up even wedging in aluminium tapers.
Two PSU's 0-30V ones a twin output digi 10A paked up twice, the others a cheapy from Maplin 0-30V analogue.
Havent done any anodising since my son broke the 4ft fish tank holding several gallons of sulphuric acid 19%. Steel doors didnt last long

Hydrochloric 33% is the one, that stings.
Dyes was a nightmare nothing worked tried the lot, in the end had to fork out for the proper powder.