Tape baking problem (backing)

  • Thread starter Thread starter TCmullet
  • Start date Start date
Vacuum and tapes

I use a vacuum pump to treat film for astrophotography. I bake the film in a converted preassure cooker sitting in an electric skillet of water. the cacuum helps get the water and oxygen out of the film backing.


This cooker would fit a 7" reel (actually 10 reels) with precise temp regulation. I don't thank that you need to pull a very deep vacuum so most any small surplus pump would work.

I'll have to give this a try. I have some sticky reels of Ampex 791 data tape. I think that a day or 2 in vaccuum and then bring the temp up to 130 for 4 hours.

The room temp vaccuum is to pull the water out of the tape and the heat is to "recondition" the oxide and backing binders. I'll have to see if heat and vaccuum will boil of any of the needed adheasives and lub.

All speculation of course. Regards, Ethan
 
Vaccuum and tape

OK (not to hyjack the thread) I just placed 4 reels of 797 (not791) in a vaccuum chamber and pumped it down to 26 inchec Hg vaccuum. You can see how primitave the setup is at: http://arafel.org/audio/

I'll leave those tapes in there for a day or 2 and them pull one out and see if there is a change in stickyness. Then at some point I'll try baking with and without vaccuum.

--Ethan
 
evm1024 said:
OK (not to hyjack the thread)
Click to expand...
No problemo, friend. On other boards have benevolently hijacked many threads myself when it seemed relevant to what was being discussed. Yes, sometimes it's hard to decide whether to start a different thread. Even my comment right this second is philosophizing over threads instead of tape-baking, so there. :)
 
Hi Anaolg Only

Just a quick jack but somewhat related. I have a few 1/4" 7 half ips reels from 1979. The producers transfered them for the first time in 20 years last week and noticed considerable gunk coming off which I assume is this sticky shedding problem. I wasn't aware that baking should be done before any playback but can't turn back time so my question is whether you can judge if they are still salvageable by listening to the sound? Really poor right now but as I have 0 experience with this any advice is much appreciated.

bad reel:

untitled

Dr Music

good reel:

I Don't Care

regards,
Tenyu
 
It's hard to tell if the muffled sound is from shedding or some other process that erased the highs. Much of the oxide that contained the highs could be physically damaged beyond repair or a strong magnetic force during storage could have done it as well.

If the tape heads were clogged with tape shed it would prevent the necessary tape/head contact to reproduce the higher frequencies. A thorough cleaning of the tape path and baking the afflicted tapes could resolve that. At this point it certainly can’t hurt.

The one thing I didn’t hear was erratic speed fluctuations or a slowing down of the tape. This is very common and the friction can even force the machine to a stop.

Good music – I hope you can salvage it.

-Tim
 
Hi Tim,

Thank you for the response. This is the Family Underground who never had a record released even though they were a huge part of the New Orleans scene. Not taking the blame from myself but shouldn't the engineer at the studio where the transfer was done known better than to play/record the reel of 7 songs after immediately noticing all the *dirt* collecting on the heads??? The producers told me he wasn't even 30 years old so should I not be surprised?

kind regards,
Tenyu
http://tenyuhamaki.com
 
tanoka said:
Hi Tim,

...shouldn't the engineer at the studio where the transfer was done known better than to play/record the reel of 7 songs after immediately noticing all the *dirt* collecting on the heads??? The producers told me he wasn't even 30 years old so should I not be surprised?

kind regards,
Tenyu
http://tenyuhamaki.com
Click to expand...

Someone there should have known. Nothing surprises me anymore though. If they don’t work with tape much they just may be out of the loop. I learned about it the hard way myself a few years ago, but I had been out of the loop myself for a while. Analog has only gained in popularity since the late 90’s, so a working studio today should learn fast if they don’t know.

-Tim
 
I may be heading toward the Walmart-special! (dehydrator)

My oldest reels have exhibited "the shed" for a while now. I've never baked a tape before. but I may do so, soon! The only mitigating factor, is that my 38 has been "down" on *very minor* maintenance, for about a year & a half! Sometimes, it's the smallest projects that take the longest,... or get put off indefinitely! :eek:

Anyway, Walmart small appliance section,... here I come!;)

Thanx for the info! I'll eventually get to it!!! :eek:
 
I was thinking that after dehydrating the reel it would be a good idea to vacuum seal it with my handy $129 food saver vacuum sealer to prevent moisture from afflicting the tape especially until we can get it cut to lacquer. Has anyone here tried this as an effective storage solution or know any issues against doing so?

thanks again,
Tenyu
 
Yes, that is a great idea. I know of a few people that are doing just that after baking. Since the binder breakdown is related to moisture, sealing should extend the life of a restored tape. :)

-Tim
 
Thanks again Tim!

I spoke to an engineer the other day who told me vacuum sealing is a great idea but cost prohibitive, well I already have the Tilia Food Saver so cheap as chips to me. Now my only concern is shipping the reels via usps from New Orleans to Brooklyn. If you have any tips or precautions for that would be great. I'm wondering if I have to worry about any x-ray post office might do or anything of that sort that could damage the tapes?

regards,
Tenyu
 
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