4 Jan
2017
4 Jan
'17
12:50 p.m.
On Jan 4, 2017, at 2:48 PM, Kyle Owen <kylevowen at
gmail.com> wrote:
On Wed, Jan 4, 2017 at 12:06 PM, Jon Elson <elson at pico-systems.com> wrote:
Electroplating sounds ok, I don't know about procedures. You'd have to be careful
that the electrolyte doesn't damage the drum body.
Evaporation and sputtering are used to make well controlled thin films, but there's
nothing I can think of that limits how long you continue. A mirror is coated only to the
point that its reflection coefficient reaches the limit of the metal used, more is not
useful. But here you could just keep going however long you need.
As for adhering, both should produce good coatings if the substrate is clean. I remember
a test for good evaporative coating technique: coat a test piece, then try to rip off the
coating with scotch tape. It shouldn't be affected at all by that test.
There are reasons for using sputtering vs. evaporation, but I don't remember them. I
think the Strong book I cited discusses the subject.
paul
Previous messages suggested the LGP-30 drum was plated with nickel. If
there are amateur astronomers with a vacuum evaporator, it might be
possible to get them to adjust their setup slightly to vacuum evaporate
nickel on your drum, after refinishing the base. You'd need a rig to
slowly turn the drum while evaporating the nickel. Some other research labs
at universities might have the necessary equipment, also - check with the
Physics department (or electrical engineering).
Will the desired thickness be enough with sputtering or evaporation? For
modern hard drives, sure, but my gut instinct is that you'd want a thicker
coating on the drum. I'd suggest sputtering over evaporation since it will
probably adhere to the surface better. I'd think nickel electroplating
would take less time and effort, though.