[vcf-midatlantic] Getting Data off old Atari Floppies

[David Riley]

On Dec 14, 2015, at 14:56, Kyle Owen via vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> 
> On Mon, Dec 14, 2015 at 1:47 PM, Herb Johnson via vcf-midatlantic <
> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
>> 
>>> Supposedly (Based on info from Chuck Guzis/sydex, though I've never
>>> tried this myself), if you dismantle the floppy by cutting open the
>>> vinyl case and removing the "cookie" inside, and put it on a baking
>>> sheet and bake it in the oven at 300F(?) for maybe 8 hours, they can be
>>> made readable again. You may need to apply some sort of sealant to the
>>> outside of the disk after baking.
>> 
>> This is, to be polite, flawed advice. There may be some confusion about
>> "baking" 1/4" audio magnetic tapes - I have no details about that process.
>> 
>> The diskette Mylar cookie will distort with heat - period. So will the
>> plastic envelope. Distortion temperatures are likely above, 120, 130
>> degrees F. I don't know the minimum. Storage above room temperature is not
>> recommended.
> 
> I thought 300 degrees F is a bit high, personally, but looking at DuPont's
> datasheet for Mylar, it looks to me like it can quite easily handle it. It
> has a melting point of 489 degrees F, after all. The shrinkage specs also
> look quite respectable; it looks like you can expect 2% shrinkage at 300
> degrees F.
> 
> That being said, most procedures I see for baking tapes rely on 130 degrees
> F. http://audio-restoration.com/baking.php for instance, cites 130 degrees
> F as being a good target temperature.
> 
> Regarding the envelope: he did say to cut open the "vinyl case" and remove
> the cookie.
> 
> Might be worth a try on those nasty Wabash disks.

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.


- Dave