On Dec 14, 2015, at 14:56, Kyle Owen via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
On Mon, Dec 14, 2015 at 1:47 PM, Herb Johnson via vcf-midatlantic < vcf-midatlantic@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