Film-Tech Forum ARCHIVE: electric rewinders

This is topic electric rewinders in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Josh Jones (Member # 447) on 09-23-2001, 10:10 PM:

First off, I am planning to have this for home use.

What is the consensous on electric rewinders? Are they prone to scratching film, for that matter, even necessary items for a changeover booth? I have worked with one that when it started up would make the noise a reel of film makes when you hold the reel stationary and pull on the tail of film. can this cause cinch marks, or scratching of some kind? I am designing a film rewind/repair bench for my booth and am curious if one of these would come in handy.

Josh

Posted by John Pytlak (Member # 331) on 09-23-2001, 10:18 PM:

If you hear the film rubbing on itself, it IS cinching and will quickly develop permanent "cinch marks".

Powered rewinds are fine, as long as they maintain constant winding tension, and accelerate gently without cinching the film. A rewind that jumps to full speed, and then slaps the end of the film when done rewinding, is asking for film damage. Tension should be just high enough to wind a tight roll without any looseness. Excessive tension will cause uneven winding ("spoking"), will stretch the splices, and may even stretch the film.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
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Posted by Ken Layton (Member # 133) on 09-24-2001, 01:18 AM:

If you have a TECO belt driven rewinder, run the belts loosely like the manual says.

Posted by John Anastasio (Member # 607) on 09-24-2001, 05:11 AM:

I wouldn't ever use one on a valuable print. I prefer to use a good hand rewind with a tensioner ...but then my right arm is starting to look like one of Popeye's. The variable speed ones with a foot controller are a lot gentler than those old enclosed film shredders. You mean you haven't BUILT one yet?

Posted by Jerry Chase (Member # 660) on 09-24-2001, 07:07 AM:

Josh, many rewinds have the manual wind handles as well as the motor. The idea is to get the film up to speed manually, and then cut in the motor to avoid cinching. Otherwise, a rheostat or other soft start device is in order.

Posted by Josh Jones (Member # 447) on 09-24-2001, 12:23 PM:

Sorry to dissapoint you John

I am saving this for a rainy, maybe blizzard day. I would also like to incorperate a light table into the bench for film inspection.

even more fun ahead!

Josh

Posted by Brad Miller (Member # 2) on 09-24-2001, 12:46 PM:

Go with an electric rewind that has a rheostat so you can have a "speed control" on it. Any powered rewind bench that doesn't have a variable speed adjustment should not be used. Also, rewinding by hand will never make the kind of quality wind possible from a motorized table and I've seen many instances where the film got cinch scratched from varying tensions. Sorry John, but no human is as consistent as a machine.

Posted by John Pytlak (Member # 331) on 09-24-2001, 12:54 PM:

I agree with Brad that maintaining constant tension on a hand rewind takes real care and effort, not to mention being tiring and building "Popeye" muscles.

Posted by John Anastasio (Member # 607) on 09-24-2001, 06:12 PM:

Yeah....It's hard getting the tension exactly even by hand. A nice even wind is something pretty to see, especially if you're using cores, and you can only do that with a motor. But I still get this craving for spinach when the film is done.

Posted by Paul G. Thompson (Member # 655) on 09-24-2001, 10:31 PM:

I have used Goldberg and other electric rewinds in my days, and never had any film damage that I detected if good straight reels were used. The tin shipping reels that were all beat up will cause lots of damage to the film. And of course, so will bent and beat up house reels.

Yes, you have to watch the tension very carefully. Some electric rewinds I used were so loose that the film actually "sagged" on the rewound reel.

When we were taught hand re-wind and inspection techniques in MPO school, tension adjustments were frequently needed. Especially when you have to start and stop to inspect a splices, and any other defect that is on the film. Cplse attention was paid to an even film pile on the reel, and even tension so that the film would not cinch the reel convolutions.

Josh, I will be happy to demonstrate these techniques to you next month. Your hand rewinds you have at present will do the job. One secret is never get in a hurry.

Paul