LGP-30 Memory Drum Update

allison ajp166 at verizon.net
Wed Jan 4 09:56:18 CST 2017

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 

> 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 

> 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.

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