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Richard and John, Thank you for the information you provided. I have a set of Tannoy monitor gold 15" speakers that have a lesser magnetic field than my oven, and the last thing I would do is to place my master tape on the speaker cabinet. So I wanted to double check that it was safe to bake the tape in my new oven. I wanted to avoid telling this new client that his precious master tape was partially erased. I can now go ahead and bring this tape back to life. Louis 2013/10/29 Richard L. Hess <[log in to unmask]> > Louis, > > I measured about 1 G very close to the motor in my American Harvest > dehydrator and about 400 mG where I usually bake tapes (near the top of the > stack). > > No one has ever complained about the American Harvest FD60 erasing tapes. > Mine is the model with the motor on the bottom, the newer ones have a motor > in the lid. > > To put this in perspective, my tape demagnetizer read 2 G at about one > foot. 2 G is the limit of resolution of my tri-axis magnetic field meter > which was in ELF mode and all three axes were measured. > > On the other hand, my studio was reading around 1 mG, more when I moved > rapidly (because I was cutting the 0.5 G earth's field). > > The canonical paper on this (maybe the only paper) is Jay McKnights at: > http://home.comcast.net/~**mrltapes/field-strength-for-** > partial-erasure.pdf<http://home.comcast.net/~mrltapes/field-strength-for-partial-erasure.pdf> > > This might be useful for converting among the differing field units: > http://www-d0.fnal.gov/**hardware/cal/lvps_info/**engineering/mag_conv.htm<http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/mag_conv.htm> > > Cheers, > > Richard > > > > On 2013-10-29 12:51 PM, Louis Hone wrote: > >> It's been a while since I've baked tapes in the oven. I'm about to embark >> on a project that involves baking half a dozen Ampex 456 quarter inch tape >> on 10.5 inch reels. We have a new kitchen oven that has a dehydrate >> setting >> (130 degrees F) so it seems perfect for the job. However, I notice that my >> Trifield Meter indicates that the magnetic field is way over 100 >> milliGauss. My old oven in which I baked many tapes, probably had the same >> reading but I never measured it. I'm not too thrilled subjecting a master >> tape to such a strong field. Has anyone else ever measured the magnetic >> field of their kitchen or tape baking oven/dehydrator ? >> >> Louis Hone >> >> -- Richard L. Hess email: [log in to unmask], Ontario, Canada 647 479 2800 > http://www.richardhess.com/**tape/contact.htm<http://www.richardhess.com/tape/contact.htm>Quality tape transfers -- even from hard-to-play tapes. >