Jack Aubert asked:
A couple of questions...
1. Is it OK to leave the piece in the anodizing bath for a long period...
I mean does it have to be removed when it's done or will it continue to
cook and spoil the finish somehow.
If you allow the anodic film to continue building it will
Tony et al.,
In Volume 2 (Mechanical) of Advanced Telescope Making
Techniques, Selected Articles from the Maksutov Circulars,
Edited by Alan Mackintosh*, Chapter 10, The Telescope Maker's
Workshop, there is an article titled, Anodizing For The
Amateur Telescope Maker by Maurice V. King. pp.
Tony,
Great stuff! Can you give any indication of how much currect is needed (per
square inch of object?).
Also, have you ever tried masking some areas of the film ( hour numbers)
before the dying process, so that they come out a contrasting (or clear)
colour?
Cheers,
John
Can I just add a note of caution to Tony's note that concentrated caustic
soda is really nasty stuff as well
as the sulphuric acid. If you get a splash of conc caustic soda in your
eye, don't bother to rush to the tap - by the time you get there it will
have already gone !!!
Have fun but BE
Roger Baily contributed:
Great, informative note. I always wondered how these coloured oxide films
were created. Thanks, I will try your techniques.
Have you, or others on the list, had any experience using caustic to
chemically etch aluminum? We used to make hydrogen to fill party ballons
and
Warren Thom wrote:
I have looked around the web for more information and found a caution of:
Because of its porosity you do not get a satisfactory anodized finish on
cast aluminium which has been machined. An as-cast aluminium surface will
not have a lusterous finish when anodized. (looks
Hi Tony,
I have looked around the web for more information and found a caution of:
Because of its porosity you do not get a satisfactory anodized finish on cast
aluminium which has been machined. An as-cast aluminium surface will not have a
lusterous finish when anodized. (looks poor)
What
Hi Tony,
Great, informative note. I always wondered how these coloured oxide films
were created. Thanks, I will try your techniques.
Have you, or others on the list, had any experience using caustic to
chemically etch aluminum? We used to make hydrogen to fill party ballons
and make mini
