- Heat colouring titanium can be controllable - support the work on
mesh and do it slowly with a cool bushy flame under it.
Colouring Niobium and Titanium:
- Anodising. Be very careful when operating the anodiser as it uses
DC Power source.
Zero to mains - 0v to 110 (or 220v in UK, Aussie, NZ etc) variable
transformer, 2A fuse, double-insulated.
DC output: 2.5 amp current. Wiring diagram available.
Electrolyte: dishwashing detergent in water.
Container: plastic salad bowl, with strainer inside the bowl.
Cathode: connect a strip of titanium to the black negative (-) lead
above the waterline, submerge the rest of the strip in between the
Anode: connect Ti wire to the red positive (+) lead and fully
insulate all parts that you handle.
About 2 tablespoons dishwash in 2 litres water. Oppi Untracht writes
of the Ti/Nb anodising electrolyte as a mix of phosphoric and nitric
acids but when reality checks in all you need is water with a bit of
resistance in it. To colour properly the current has to travel from
the anode wire (+) to the work, then through the electrolyte, to the
Put the work piece in the electrolyte and prepare to touch it with
the (+) wire. It won't scratch the surface.
You cannot say that one voltage will produce one colour. The colours
are voltage-dependent to a degree, but not entirely, as size of the
workpiece has a big bearing on the colour at any one voltage. Switch
on power at (say) 25v and watch the colour happen. With the voltage
setting at the one low setting such as 25v the whole piece will
become a colour all over depending on ths size factor. Just wing it
for the colour you want. Raise the voltage and try for another
colour. Watch and see.
It's not a given that all anodised Ti (and niobium) will come out
even-coloured. Surface quality has a bearing so degrease the piece
well. Parts near the cathode get coloured earlier, and it's
irrespective of where you touch the anode wire to the work. Pointy
and narrow bits colour up earlier too. Unlike anodising aluminium
where very dangerous currents are used, in anodising the reactive
metals the amperage is lower (way less than an amp), so no arcing
happens where the anode wire touches, except at about 150v up.
I recommend you buy the anodising machine from Reactive Metals. They
sell a lot of other useful stuff - get their paintbrush attachment
and paint your designs.
NO RESPONSIBILITY, the usual riders etc, for all this advice. I
don't know how competent you are with this sort of equipment.
B r i a n A d a m a n d R u t h B a i r d
AUCKLAND New Zealand