Question about DECtape formulation

Tom Gardner tom94022 at comcast.net
Wed Jan 26 12:28:42 CST 2022


> On Jan 24, 2022, at 10:27 PM, Gary Oliver via cctech
<cctech at classiccmp.org> wrote:
> 
>> ...
> 
> As to the real reason I was doing this: Most of my tapes are un-boxed and
have suffered being in a dusty area (before I got them) with the dust
forming a sort of 'crust' on the outside of the tape.  It's only on the
first wrap or so, but it's enough that it keeps those handy vinyl cohesive
tapes from sticking.  For that reason, I was trying to find something to
clean of this dusty gunk so the vinyl strip would hold the tape into a
spooled condition. It was the side-effect of this effort that lead me to the
discovery if this "removable layer" on the DECtape.
> 

I talked to a friend who was at DEC during the days of DECTape and
thereafter, his comment:
..."I think it is a thin version of the base material, some flavor of
polyester film.  Most likely a 3M tape.  The bit density is so low a little
spacing doesn't matter much.
...The UNISERVO I, of Univac I, tape drives had a separate spool of clear
very thin film that was clock motor wound across the head when tape was
moving, since the phosphor bronze plated tape was very abrasive.  That
existed long before LINCtape/DECtape."

Note that LINCtape is DECtape :-)

Tom



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