[vcf-midatlantic] Getting Data off old Atari Floppies

[Herb Johnson]

David Riley:

>> Chuck's advice was to do what he did: make a plywood box,
 >> put a 25W bulb in, and "bake" it in there for a few days
 >>  (sans vinyl jacket). That won't get you above warping
 >> temperature. Please don't bake any plastic-based media
 >> at 300F.

Did Chuck say why to do this, what this baking would accomplish? The 
previously referenced Web page which discusses baking audio tapes says:

"The purpose of "baking", is to drive out all the moisture that the tape 
binder has accumulated, which is what caused it to go sticky in the 
first place."

I do not know that this applies to diskettes and the binders used on 
their surface coatings. another Web page on baking tapes is:

http://www.wendycarlos.com/bake%20a%20tape/baketape.html

..and one Google search hit for "guzis bake diskettes" says, Chuck baked 
*10-inch tape reels", not diskettes; and the thread was about baking 
TK50 tape cartridges. Read the thread.

https://www.mail-archive.com/cctalk@classiccmp.org/msg04318.html

[Re: TK50/TK70 Info,  Chuck Guzis Fri, 28 Aug 2015]

another "hit" is on the mark: here's an exerpt.

http://marc.info/?l=classiccmp&m=137627575108631&w=2
    [classiccmp list
    Re: MFM floppy disk write precompensation
     Chuck Guzis,  2013-08-12 2:18:15]

Sure, remove the cookies from the jackets, bake them at 140F for 4 or 5
hours, then apply a good-quality synthetic auto paint sealant--Klassic
seems to be pretty good.  No abrasive polishes, please.....

That seems to provide a slick enough surface to keep the heads from
grabbing the oxide--at least for a few reads.  The alternative is 
disaster....Basically, you want to prevent the heads from "grabbing" the 
oxide. Once that starts, you're looking at a circle that you can see 
through. Get yourself an old box of Wabash floppies (any size) and play 
around......[end excerpt]

---------------

Kyle Owen, good student he is, did his homework, and corrected my 
assumption that the Mylar would buckle - it's much more temperature 
tolerant, which you'd want for a stable magnetic backing. Thanks, Kyle!

In any event, I did an uncontrolled experiment. Briefly: several minutes 
of baking an 8" diskette envelope (probably PVC?) and the diskette media 
cookie (Mylar coated with oxide) at 110-120 degrees F, did not seem to 
immediately distort (melt) either cookie or envelope. But minutes into a 
180 degree spike, turned the envelope to a waffle, and put noticeable 
distortion into the cookie. When cooled, the cookie showed some 
distortion - I could not say it was sufficient to cause read errors. Of 
course the envelope was trashed.

Again - I'm not convinced baking floppy diskettes, will solve any 
problems with mold or "moisture", which occurs more often than "flaky" 
diskettes. Chuck Guzis - who has informed me many times through the 
decades on matters floppy - seems to use this method to re-bind magnetic 
coatings on diskettes. and that's consistent with the same method, used 
to re-bind magnetic coatings on a certain class of 1970's audio tapes, 
some old DEC magnetic tapes, etc.

This was informative discussion, thanks!

Herb Johnson



-- 
Herbert R. Johnson,  New Jersey USA
http://www.retrotechnology.com OR .net