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Baking analog master tapes
Old 5th July 2005
  #1
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Tim Farrant's Avatar
 

Unhappy Baking analog master tapes

I have two 1/4" master tapes, (Agfa 469 circa 1986), which I have baked twice now in the recommended fashion (50 degrees C for 4 hours) and still they are still sheding oxide.

Has anyone had experience with this? Is there anything more we can do to get these to play just once more for transfer?

Thanks in advance
Cheers
Tim
Old 5th July 2005
  #2
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brianroth's Avatar
 

Hmmmmmmmm...two things come to mind. Do the Agfa tapes exhibit sticky shed (ie, leave a gummy mess on the tape guides, often to the point where the sludge will completely stall the tape while in play)? Baking is intended to fix that...turn the sludge back into something more solid. Dry shedding is another whole problem and I don't know the answer.

If it IS sticky shed, try 6 or more hours of baking.

Bri
Old 6th July 2005
  #3
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Tim Farrant's Avatar
 

Hi Brian,
yeah, it's sticky shed. I've baked them twice already, total 8 hours or more, I think the last time it was more like 6. I've done many other tapes with great success so a bit baffled, maybe these are just beyond repair now?

Tim
Old 6th July 2005
  #4
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brianroth's Avatar
 

Maybe Agfa requires a different procedure than Ampex tape? I never had to deal with a SS roll of Agfa, so I'm drawing a blank.

Bri
Old 11th July 2005
  #5
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I have heard of higher temperatures, please look that up seriously..
(fahrenheit..?)
Old 11th July 2005
  #6
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Tim Farrant's Avatar
 

I have been given some specific instructions from the generous people at Fogolabs in Canada, thank you Francois and Matt. Matt has suggested I bake again for 10 hours with one spool flange removed, so I will give this a try and let you know the outcome.

Cheers
Tim.
Old 11th July 2005
  #7
Here for the gear
 

Hi Tim,

Sounds like you have been given some good advice. I thought I'd share some of my experiences with you. I have baked 1000+ radio archive tapes over the past two years on an archival project.

We use a lab oven set at 57 degrees C. I usually bake the tapes for 10-12 hours. Almost as important as baking is the cool down time. I've found you should cool down for the same time as you spent baking.
I have run into an occasional stubborn tape that was still sticky after baking. In those cases, I baked again for 12 hours and cool for 12. One case, I had to do this 3 times, it then worked.

I have found Ampex tapes to be the stickiest. Fortunately, most of our archived material is all 3M (thanks to being in St. Paul, Minnesota). The 3M tapes had the least amount of sticky shed problems.

Hope that helps.

Scott
Old 14th July 2005
  #8
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Drumsound's Avatar
Are the tapes useable after baking, or will you just get one play?
Old 14th July 2005
  #9
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Quote:
Originally Posted by Drumsound
Are the tapes useable after baking, or will you just get one play?

From my experience, the tapes were playable numerous times up to a point that the binder reabsorbed moisture again from the air. In most cases, the tapes were good after baking for at least a month. YMMV depending upon humidity conditions.
If the tapes absorb moisture, baking them again restores them to a playable condition. It is conceivable that this process could be done many times with no damage to the tape.


Scott
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