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» Film-Tech Forum   » Operations   » Film Handlers' Forum   » Kelmar film cleaner moving too slow?

   
Author Topic: Kelmar film cleaner moving too slow?
James R. Hammonds, Jr
Jedi Master Film Handler

Posts: 931
From: Houston, TX, USA
Registered: Nov 2000


 - posted 02-14-2001 09:14 PM      Profile for James R. Hammonds, Jr   Email James R. Hammonds, Jr   Send New Private Message       Edit/Delete Post 
When I went back to work at one of my old theatres, I was told by my booth manager that he had quit using film-guard because the motor for the film cleaner itself was moving too slow, which he thought may have been allowing (but not neccessarily being the only reason for) prints to be scratched due to film being run over excessive dirt biuld-up.
We later used one of these film cleaners to apply film-guard to a print we were having static problems with and when the print was over, I had noticed that the used portion of the media pads were only about 1/4 of an inch thick, when normally, the pad would have been almost halfway through.

Has anyone else had this problem, or know what could cause this?
Could there be dirt biuld-up inside the film cleaner itself that is causing the media pads to move so slow?

Randy Stankey
Film God

Posts: 6440
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 02-14-2001 09:32 PM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
There are a couple of things that come to mind:

1) The rubber around the edges of the drive "tire" might not be gripping the film well enough, thereby not moving the mechanism fast enough (or not at all)

My solution for this has been to take a Q-Tip® and apply a little FilmGuard® to the rubber. It "regenerates" the rubber enough to make it grip again. Also, you should check your film path to make sure things are right. If all that fails, you can get replacements to put around the edge of the drive tire.

2) The rubber inserts in the center of the take-up spindles might not be gripping tight enough. They work by compression: The tighter you tighten the screws, the more they get squashed and the tighter they grab the take-up spool. If there's something wrong there, even though the thing is running properly the media won't get pulled along as it should.

You could take a look inside and see if there's something amiss there but you'll find out that there really IS nothing inside the things besides a couple-three drive sprockets and some jack chains. I'd say that since the thing is taking up the media at all the problem doesn't lie there.

If both media spools are taking up evenly then I'd go for option #1. If both spools aren't taking up the same (or nearly the same) amount of media then I'd go for option #2.


Michael Cunningham
Expert Film Handler

Posts: 186
From: Anchorage, AK
Registered: Nov 1999


 - posted 02-14-2001 09:41 PM      Profile for Michael Cunningham   Email Michael Cunningham   Send New Private Message       Edit/Delete Post 
What drives these film cleaners is the film passing around the large "wheel" like hub in the upper right corner of the cleaner. Inside the cleaner, this hub's shaft is connected by a chain (think bicycle) to gears on the media shafts. These gears are sized to translate the speed of the hub down to a lower speed for the media. What I would check for your too slow media is that the film has enough tension as it passes around this hub. If the film is not firmly against it, it may not be rotataing at the same speed as the film passing around it.

-Mike

Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000


 - posted 02-14-2001 11:04 PM      Profile for Darryl Spicer     Send New Private Message       Edit/Delete Post 
Had this problem before. The film is actualy slipping on the rubber of the large drive wheel. I have found that if you apply a little wd-40 to the large wheels internal spindle and all the media shaft spindles on both sides of the internal area. This will free up the mechanisms allowing the cleaner to spin more freely.

Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 02-14-2001 11:53 PM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
Do yourself a favor and throw that WD-40 out of the booth. Sure, it smells nice, but when you spray it on something and the solvent evaporates, all you have left is a gummy goo that makes it work worse. WD-40 is good for loosening a rusty nut or bolt. But that is as far as it goes. I have seen people use in on Twist rods of LP platters, the dancer guide rods on CFS, Potts, and Strong platters, and a week later, they are sluggish as hell until you re-clean them with stoddard solvent or denatured alcohol. I have also seen some idiot technician use that stuff on lateral sound guide rollers, and then they can't figure out why they get sluggish, and do not return to optimum position after a crappy splice goes through them. WD-40 is a disaster in the booth. I don't allow that stuff in my booths, period! I have seen the headaches it causes.

Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000


 - posted 02-15-2001 12:16 AM      Profile for Darryl Spicer     Send New Private Message       Edit/Delete Post 
Use three in one oil then.

Randy Stankey
Film God

Posts: 6440
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 02-15-2001 12:27 AM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
I wouldn't use 3-in-1. Not only is it bad for the film but it can also eat the rubber and make the problem worse.

If you are using FilmGuard in your booth there should already be small amounts of it getting on the rubber. That ought to be enough to keep the rubber in good shape. If you need a little more you can use just a touch of FilmGuard on a Q-Tip and rub it on the rubber.

If your rubber rings are getting really yucky you might have to replace them. (Sometimes they dry out and crack.)


Brad Miller
Administrator

Posts: 17695
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 02-15-2001 12:29 AM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
Some of these may have been listed above.

Are you using Christie platters with the center brain back-tension spring in place? If so, the higher feed tension will make the takeup roll wind tighter and pull less media per foot of film.

The main large drive wheel could be the culprit. This is generally caused by a dropping of the cleaner itself, which bends the shaft just enough so that it does not spin freely. Occasionally it just needs lubrication. Whatever is the cause, that should spin freely.

Those little rubber inserts in the takeup shafts are notorious for hardening up and not gripping the takeup core after a certain amount of usage. The good news here is they are dirt cheap to buy and every dealer I know of stocks them. When you have loaded your new roll of media onto the cleaner and tightened down the takeup thumbscrew, try and spin the takeup core by hand. If it does not slip, you are fine. If there is some slippage, you can "buy time" with those old rubber inserts by sandwiching an appropriate sized washer in between the thumbscrew and top plastic shaft. Such a washer (sometimes it take 2 or 3) must not have an outside diameter larger than the inside diameter of a core. This is the ideal temporary fix, but finding washers of that size is hard to come by. A less than ideal fix (but which works just as well) is to place a large washer at the bottom of the entire takeup assembly (on the narrow non-removable shaft). This washer must have a center hole just larger than the shaft to work properly and you must be careful to tape the media to the takeup core straight, since the modified takeup shaft will not place the core in direct alignment with the supply roll. (I know this is confusing, but I'll try and take some pictures in the next couple of weeks and post here.)

Another possibility is on the older units that are chain driven as opposed to the newer gear driven ones. Sometimes the chain drive pulley slips on the shafts and all that is needed is a retightening of the allen set screw.

Finally, your speed problem may be nothing more than the type of media used. Different media is made in different thicknesses and a thinner media will wind slower than a thicker media. Remember also that the media pulls faster and faster as the roll runs through, since the takeup shaft turns at a constant tension while the outer diameter of the takeup roll increases with every turn. For this reason, a 90 minute film may look like hardly any media was pulled, but a 2 hour film may look like a substantial amount of media was pulled.


Darryl Spicer
Film God

Posts: 3250
From: Lexington, KY, USA
Registered: Dec 2000


 - posted 02-15-2001 12:33 AM      Profile for Darryl Spicer     Send New Private Message       Edit/Delete Post 
Randy, I was just making a joke Just use a little light projector oil inside the gear compartment on the individual shafts instead of wd-40. I have not had a problem using wd-40 but to each his own. just a little to lube up the shafts.

Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000


 - posted 02-15-2001 12:49 AM      Profile for Paul G. Thompson   Email Paul G. Thompson   Send New Private Message       Edit/Delete Post 
WD-40 is a water displacement compound in addition to loosening any rusted nuts and bolts you might have. Not a lube. The more you use it as a lube, the more trouble you will have with the unit you are using it on, which means, MORE WD-40! When that residue WD-40 leaves behind builds up, you have been snapped by an alligator.



Randy Stankey
Film God

Posts: 6440
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 02-15-2001 08:54 AM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
Honestly, I have never had very much trouble with WD-40 on anything. You're not the first person to tell me about the ills of the stuff, either.

The only time I've had trouble with it was when I was out hunting. We had used it to do an "emergency cleaning" of my shotgun. (I was duck hunting and I dropped the shotgun in the water.)

Well, it started to get cold later on and the WD-40 started to gum up. It got so bad the gun was unusable. (It was a Rem. Mod. 1100)

Normally, when I use WD-40 on guns (or anything else, for that matter) I always make sure I wipe it as dry as I can. Maybe that's the reason I never had trouble, except that once.

John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999


 - posted 02-15-2001 12:31 PM      Profile for John Walsh   Email John Walsh   Send New Private Message       Edit/Delete Post 
Don't forget that older Kelmar/Christie film cleaners only ran for about two hours. Then they changed them (changed the ratio) to run slower, since most newer films ran over that.

John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 02-15-2001 04:55 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
One way to tell if the film is slipping past the drive roller of the Christie web cleaner would be to calculate or measure the exact circumference of the roller (I recall it is probably somewhere close to 12 inches). Then divide it into the 90 feet per minute transport speed of 35mm film. Then count the number of revolutions the drive roller makes per minute, and see if it is much less than what you calculated it should be if there were no slippage.

For example, if the circumference were exactly 12 inches (one foot), then film moving at 90 feet per minute should drive the roller at 90 revolutions per minute (90 RPM) if there is no slippage. As noted by others, if there is significant slippage, be sure the mechanism isn't binding or the film tension isn't wrong.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion




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