[vcf-midatlantic] Getting Data off old Atari Floppies

[Jonathan Gevaryahu]

On 12/14/2015 6:50 PM, David Riley via vcf-midatlantic wrote:
> 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
>
>
Yeah 300F was completely wrong, I was mixing baking floppies up with 
baking EPROMS after x-ray (not UV!) based erasure (which really does 
need 300F).

-- 
Jonathan Gevaryahu
jgevaryahu at gmail.com
jgevaryahu at hotmail.com