Hi all,
This is something I've wondered about for quite some time now, and with a number of video tapes (cassettes) containing "never to be seen again" and "one off productions" I have good reason to want to know how best to avoid ruining irreplaceable recordings.
I've heard of 'baking' tapes, but what does that entail? Obviously, we're not talking "Gas Mark 7" for 45 mins!
I can envisage warming cassettes at a very low temperature for long periods of time to drive off absorbed moisture, but is it really as simple as that? Any heat applied cannot be much, otherwise the tape would warp and shrivel, and as we all (?) know, heat will destroy any magnetic recordings (moreover, the tiny magnetic fields that constitute the recording) - try burning any magnet, like the ceramic magnets from speakers, or focus magnets from a vintage TV, and the result is a 'dead' ceramic ring with very very little or no magnetic flux.
So is there a black art involved? Or is there some high tech process known only to Merlin and the television companies?
Four recordings in my N1700 range immediately come to mind as prime candidates;
1. "Home from from the sea" - the full length, live broadcast of the decommissioning of HMS Ark Royal (1979).
2. "Bing Crosby - The Christmas years" - A special recording made after the sudden death of Bing Crosby, and featuring parts of what were to be that year's (1977) Christmas show, sections from shows over the preceding 'television' years, and personal continuities by the Crosby family.
3. "Once in a lifetime" - single episode covering the shrimp fishermen of Morecambe Bay (circa 1980) using "tractor trawling" techniques, literally, adapted Nuffield tractors and specially built floating trailer/trawlers. Featuring Cedric Robinson, the then official guide to Morecambe Bay (by royal appointment).
4. "Balloon over Yorkshire" - Featuring the fabled Sid Perou (cameraman) renown for his breathtaking daredevil camera work. (BBC Leeds 1982).
There are many more, but these four stand out as the ones I'd really like to see again.
Marion
It's more a question of dealing with the plasticiser. You won't kill the magnetism unless you exceed the temperature at which the Curie Effect takes place.
From memory, the tapes are baked at around 60° C?
Hi Mike,
That was very interesting, thanks.
Following a link in there took me to more detailed information, or read as tales of doom.
It seems then that an accurately controlled oven is required, and tapes more than ten years old are not good news.
I'll have to dig out the tapes and see what they're looking like. Then one of the recorders will need restoring before anything else, though it seems it would not be a bad thing to bring the tapes up to a suitable temperature, and down to a suitable humidity straight away.
This could be an interesting challenge, to say the least, but the primary objective is to make digital copies of whatever, if any, I can salvage.
Marion
The only video tape I've ever had problem with is 405 and early 625 open-reel tape (some skip-field!) of the Sony brand. The scotch tapes of similar vintage seem to be holding up OK.
I've never had the problem with any video cassette tapes! Even my oldest N1500 cassettes are still OK. There will be drop-outs etc, but I've never had the sticky plasticiser or shedding issues with any.
If I was worried, I'd devise some method of winding the tape, keeping away from the video head drum, and look to see what's coming off.
If only I could say the same for the miles of Racal Zonal audio tape I have ....
Are they Scotch Tapes? 
Frank
nuvistor said
Are they Scotch Tapes?
1983... oh dear, I do feel somewhat ancient now ....
Doz said
1983... oh dear, I do feel somewhat ancient now ....
1983, It was only three years ago...... wasn't it ? Someone please say it was and dispel my idea of a great passage of time. 
To understand the black art of electronics is to understand witchcraft. Andrew.
Voiced by Derek Guyler, no less.......
Ironically, I know there are a good few vintage adverts on some of my N1700 recordings, in their day, nothing other than a nuisance, now themselves worth preserving.
Funny isn't it, how we threw away then, the things we treasure today..?
Somewhere in my cabin, there is a long lost "mini-fridge"..... Those little tabletop insulated boxes with a big heat sink, both in and outside the box, and a pair of fans on a common motor shaft.
As with most of these mini-fridges, this one can also heat things up - there are a couple of aluminium clad high wattage resistors (read as heating elements) attached to the inner heat sink. It can certainly warm up a pie/pasty to a nice, edible temperature, and my thinking is that if I can find a suitable thermometer I can test the actual temperature generated, and if suitable, this could be the way to bake video cassettes. Naturally, I'd perform some simple tests on a couple of unimportant VHS recordings to make sure the cassettes don't melt or the tapes shrivel up, and of course to make sure the recordings aren't destroyed by the heat.
One definite advantage is that the internal fan moves the air around inside the box so that anything inside will be uniformly heated, and the moving air will aid evaporation of moisture.
Just a thought, and since these things aren't particularly expensive it would be no big hardship to get another if I can't find my own.
Marion
I've got one of those little fridges too, the one I have uses one of those Peltier elements, so changing the polarity to it changes which side gets hot, and which gets cold, all done by a switch on the back. A quick thought for getting the temperature right inside it, you can get little digital thermostat modules that you can set the temperature you want, wouldn't be too difficult to fit one to it.
Quite useful little fridge to have in the workshop, I used to keep superglue in mine that needed to be kept cold, and also useful in the summer to keep a pack of biscuits in to stop the chocolate melting! I never thought of using it on hot for baking tapes, I might try it on some NOS Ampex reel to reel tapes I got that leave sticky stuff everywhere.
Regards,
Lloyd.
As a side note I believe that Cedric Robinson is still the queens Guide to the removed link
I too have a N1700 Machine, plus almost a second for removed link I'm hoping to obtain some belts soon and a tape or two so I can finally test the machine!
Moderator note: In case you're wondering where your links have gone, its an automated anti-spam forum policy to disallow a new members first post to contain links or attachments. You'll find no such restriction on subsequent posts.
nuvistor said
Are they Scotch Tapes?1983... oh dear, I do feel somewhat ancient now ....
Preferred this ad, myself:
As a side note I believe that Cedric Robinson is still the queens Guide to the removed link
I too have a N1700 Machine, plus almost a second for removed link I'm hoping to obtain some belts soon and a tape or two so I can finally test the machine!
Moderator note: In case you're wondering where your links have gone, its an automated anti-spam forum policy to disallow a new members first post to contain links or attachments. You'll find no such restriction on subsequent posts.
The good news is that there is a guy in Budapest, who makes sets of belts for these machines. The belts are made up in small batches and can be bought via eBay. I have a set waiting to be fitted.
Now, with regard to Cedric Robinson, I wasn't sure if he was still guiding these days - he must getting on in his years?
One thought that's been on my mind for a little while.... Is it really necessary to actually heat the tapes? Or would it be sufficient to use a dehumidifier (or desiccant gel sachets) to simply extract the moisture. Or is it more complex than that? Here, I'm thinking perhaps the elevated temperature is necessary to 'fix' the recording surface - fix, as in make fast/secure, as opposed to repair/mend.
