4 Jan
2017
4 Jan
'17
7:56 a.m.
On 1/4/17 10:19 AM, Al Kossow wrote:
On 1/4/17 7:03 AM, Klemens Krause wrote:
> We have a second LGP-30 drum in our museum. It is damaged by water.
> (large rusted areas, probably from water between heads and drum).
> I'm dreaming to wash the brown oxide coating off with a solvent like
> acetone, polish the drum and repaint it.
> As magnetic paint I would try iron oxide from audio tapes solved in acetone or some
other solvent.
> Perhaps one could ask an airbrush artist to do this.
> Rumours say, that the drums originally also were coated "by hand".
>
The was a post application "calendaring" process to get a uniform
smooth
surface.
In doing some disk research recently, I came across a
footnote for a rather unlikely
place to find information on magnetic coatings, which I just got a copy of:
Patton "Pigment Handbook Volume II Applications and Markets" 1973
Kurt Kreiselmaier "Pigmentation of Magnetic Tapes" pp 315-329
Which goes through the whole process at a high level of how magnetic tape is made,
including aligning all the magnetic particles on the surface. They also mention sperm
oil being used as one of the ingredients (I had wondered if there was documentation
for that claim), and about two dozen patents at the end.
Sperm oil was a high
quality wax/lubricant. Its low viscosity and high
resistance to oxidation
were its high points. Its likely use was as a plasticize the binder and
surface.
There is also a lot of information in the book on
colorizing agents for plastics.
I'll put a scan up today under midwesternUniveristy, where Kreiselmaier was an asst
prof.