Hi All,
Some would vote for slate, but for my money anodised aluminium is just about
the best material for a dial. It shows shadows brilliantly, can be coloured
brightly and with very fine detail by a photoresist process as John Davis
has shown. Its surface is very hard and very resistant to weathering.
But, here in the UK at least, it appears that it doesn't have the cachet of
brass, bronze and stainless steel. Too bad.
I'm sure that sandblasting was discussed once on this list as a method of
dulling the mirror reflections from stainless, but perhaps that isn't the
appearance you're after here.
Chris Lusby Taylor
51.4N 1.3W
----- Original Message -----
From: "Ricardo Cernic" <[EMAIL PROTECTED]>
To: "oglesby" <[EMAIL PROTECTED]>
Cc: "sundial" <sundial@uni-koeln.de>
Sent: Friday, April 25, 2008 1:20 AM
Subject: Re:Request for suggestions
Hello Mac,
I know you intend to use stainless steel, but even this kind of steel can
present oxidation problems if it is not top quality.
Have you considered using anodized aluminum? After anodization this material
can be dyed with special dyestuffs of many colors and sealed with a nickel
salt. This surface treatment improves the resistence of the surface at the
same time it gives a homogeneus color that has an awsome oxidation
resistence. The light fastness is also very good and the color will last for
many years. This kind of treatment has been used in satellites and
spacecrafts, masts for sailboats, window frames in buildings, etc.
Best regards,
Ricardo Cernic
São Paulo - Brazil
---------- Início da mensagem original -----------
De: [EMAIL PROTECTED]
Para: "Sundial Mailing List" sundial@uni-koeln.de
Cc:
Data: Wed, 23 Apr 2008 20:59:16 -0400
Assunto: Request for suggestions
>
> Hello friends,
>
> Does anyone know a simple, safe, and inexpensive method to
> permanently darken stainless steel?
>
> I'm involved in a project to create a vertical decliner (48 inches
> wide by 30 inches high by 1 inch thick cast concrete) sundial for our
> town's Municipal Center showing hours until sunset. For the hour
> lines we intend to use 1/4 inch square stainless steel bars imbedded
> into the concrete.
>
> Test castings show that, when sunlit, the imbedded bars appear dark
> from most viewing angles, but that from some angles reflect light so
> as to almost disappear. Although the changing appearance of the hour
> lines might be considered a positive feature, I'd rather the hour
> lines always looked dark.
>
> Thanks for any suggestions.
>
> Mac Oglesby
>
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>
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