Feb 16, 2018

veiled effect on colour

1 comment

Hi there. I have been experimenting with anodising titanium for a little while, along with a friend. We have different set-ups, and I am following the technique outlined by Bille Seeley (SMT, TSP, etc). My friend uses sulphuric acid in place of TSP, which is something I do not want to do. His colours come out clean and pure (no mottles etc). Mine, on the other hand take forever to change, even at lower voltage, and have an effect that I can only describe as like a translucent white veil over them..

 

The preparation and cleaning is identical - I have prepared pieces for my friend in helping him with a collection.

 

Any clues?

Feb 16, 2018

Hi Ozzy, Firstly, it is not necessary to use sulphuric acid as your electrolyte--it is a carry over from anodizing aluminum. It actually makes no difference for the titanium.

 

Secondly, the veil you are seeing is likely oxide. Any time you see pastel or mottled colors instead of bright clear colors, that is oxide. This provides resistance which is why it takes forever to change color (assuming your mixing ratio of TSP is correct: Regular TSP=1 and 1/3 cups per gallon distilled water, TSP-PF= 1/2 cup per gallon distilled water).

With titanium you must remove this oxide by either chemical means (we prefer Multi Etch) or physical means. You didn't mention what grade of titanium you and your friend are using. This could also have some bearing. Grades 1-4 (Commercially pure) will always need etching first. Grades 5 & 23 (6al/4v alloy) very often don't need etching unless you are trying to hit higher voltage colors.

 

Just to make sure your steps are correct, here's a basic step order:

1. Clean & degrease pieces (we like heated simple green)

2. Rinse in distilled water (or Reverse Osmosis)--so you don't get mineral spots from hard water

3. Multi Etch (or physical removal)

4. Clean & degrease

5. Rinse in distilled water

6. Anodize immediately. **Note: Titanium will rebuild it's oxide layer when in contact with oxygen, so at the very least, anodize it up to 5-10 volts to "seal" the etch in. That way you can come back in a year and color up to whatever color you want without etching again.

7. Rinse in distilled water

8. We prefer blowing dry with a hair dryer vs air drying

 

Hope this helps!

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