Plastic Film Cassettes Jamming

I use the plastic film cassettes for reloading. Lately, after reloading
they're sticking. I loosen the cap a bit and they spin quickly once the
tension is off. It's like I'm tightening the cap too much. But this was
never a problem in the past. Does the cap tend to "work in" after many
reloads with this type of cassette? I've tried cleaning the surfaces with
isopropanol and it makes no difference. Should I try "oiling" them? Is it
just time to throw them out? Thx.

Alan Smithee wrote:
I use the plastic film cassettes for reloading. Lately, after reloading
they're sticking. I loosen the cap a bit and they spin quickly once the
tension is off. It's like I'm tightening the cap too much. But this was
never a problem in the past. Does the cap tend to "work in" after many
reloads with this type of cassette? I've tried cleaning the surfaces with
isopropanol and it makes no difference. Should I try "oiling" them? Is it
just time to throw them out? Thx.


I never noticed this, but the end caps are not all the same. You may have
the caps on the wrong cassettes.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 11:00:00 up 16 days, 13:20, 3 users, load average: 4.31, 4.37, 4.29

"Alan Smithee" wrote

I use the plastic film cassettes for reloading. Lately, after reloading
they're sticking. I loosen the cap a bit and they spin quickly once the
tension is off.

It is call 'galling', usually referring to wear of metal surfaces but it
happens with all solids.

If a substance is rubbed against itself it will raise microscopic balls and
make tiny gouges. The gouges and balls interlock and you get a lot of
'sticktion'.

To counter this sliding surfaces should always be of dissimilar materials,
one hard material and one soft material. The soft material can not deform
the hard material and the hard material wears the soft material to a smooth
conforming surface so the load is distributed evenly and the soft material
does not wear away after the parts are 'worn-in'.

When the cassettes start to stick then the only thing you can do is chuck
them, things will only get worse, oil won't help. Lubricating _new_
cassettes may give a bit more life to them but eventually you will get
galling. Try an infinitely thin coat of Vaseline, lubriplate or silglide.
The right stuff is an olefin grease [you might try butter]. I find vacuum
grease to be excellent as it does _not_ migrate.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm

I thank you. This seems to be my problem. "Stiction" as you have so pointed
out. I hate using the metal cans so I guess it's time to stock up on the
plastic ones.


"Nicholas O. Lindan" wrote in message
ink.net...
"Alan Smithee" wrote

I use the plastic film cassettes for reloading. Lately, after reloading
they're sticking. I loosen the cap a bit and they spin quickly once the
tension is off.

It is call 'galling', usually referring to wear of metal surfaces but it
happens with all solids.

If a substance is rubbed against itself it will raise microscopic balls
and
make tiny gouges. The gouges and balls interlock and you get a lot of
'sticktion'.

To counter this sliding surfaces should always be of dissimilar materials,
one hard material and one soft material. The soft material can not deform
the hard material and the hard material wears the soft material to a
smooth
conforming surface so the load is distributed evenly and the soft material
does not wear away after the parts are 'worn-in'.

When the cassettes start to stick then the only thing you can do is chuck
them, things will only get worse, oil won't help. Lubricating _new_
cassettes may give a bit more life to them but eventually you will get
galling. Try an infinitely thin coat of Vaseline, lubriplate or silglide.
The right stuff is an olefin grease [you might try butter]. I find vacuum
grease to be excellent as it does _not_ migrate.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm

Alan Smithee wrote:
: I use the plastic film cassettes for reloading. Lately, after reloading
: they're sticking. I loosen the cap a bit and they spin quickly once the
: tension is off. It's like I'm tightening the cap too much. But this was
: never a problem in the past. Does the cap tend to "work in" after many
: reloads with this type of cassette? I've tried cleaning the surfaces with
: isopropanol and it makes no difference. Should I try "oiling" them? Is it
: just time to throw them out? Thx.

How long have you been using the cassettes. While I prefer the plastic to the
metal one the plastic ones don't last very long.

--




-------------------
Keep working millions on welfare depend on you

I've had the same batch for a couple of years. They all get used in
rotation. Is sticking the number one cause of plastic cassette failure?


"Frank Pittel" wrote in message
...
Alan Smithee wrote:
: I use the plastic film cassettes for reloading. Lately, after reloading
: they're sticking. I loosen the cap a bit and they spin quickly once the
: tension is off. It's like I'm tightening the cap too much. But this was
: never a problem in the past. Does the cap tend to "work in" after many
: reloads with this type of cassette? I've tried cleaning the surfaces
with
: isopropanol and it makes no difference. Should I try "oiling" them? Is
it
: just time to throw them out? Thx.

How long have you been using the cassettes. While I prefer the plastic to
the
metal one the plastic ones don't last very long.

--




-------------------
Keep working millions on welfare depend on you

I've never seen this but I will only use a cassette a few times before
discarding it.

My theory is that the cassette felt gets dirty and increases the chance of
scratching the film (even dust and small film particles from the bulk roll
could contaminate the felt) and that repeated use can wear enough "fuzz" off
the lips to increase the chances of fogging the film. Metal cassettes are
easier to blow clean but even easier to misalign the lips so may be less
prone to scratching and more likely to fog the film.

I mark each cassette each time I use it, after the fifth reload I'll use it
only for non-critical applications, such as copy work or camera and lens
testing. I also use photo-lab "twin-cheks" even when I process my own film
so I know which roll came from which cassette and can toss any offenders. I
have a lifetime supply that I got from mini-labs that I work at. Given to
me when we found they wouldn't stay on at 100 deg. F. (they work fine at the
temps I'm likely to use to process black and white film!).

And just a thought, not all plastic cassettes are made by the same plant on
the same set of molds so you could have problems if you've switched lids or
spools around between cassettes. I'm very careful when I use plastic
cassettes to keep all the pieces together as I load and unload them, using
ice cube trays to keep all the bits together.

--
darkroommike

"Alan Smithee" wrote in message
news:SbhQf.132767$B94.22447@pd7tw3no...
I use the plastic film cassettes for reloading. Lately, after reloading
they're sticking. I loosen the cap a bit and they spin quickly once the
tension is off. It's like I'm tightening the cap too much. But this was
never a problem in the past. Does the cap tend to "work in" after many
reloads with this type of cassette? I've tried cleaning the surfaces with
isopropanol and it makes no difference. Should I try "oiling" them? Is it
just time to throw them out? Thx.

"Alan Smithee" wrote

I use the plastic film cassettes for reloading. Lately, after reloading
they're sticking. I loosen the cap a bit and they spin quickly once the
tension is off.

Ah, I may have read this wrong. I have had trouble with the screw on
plastic caps sticking and projected my experience.

If the problem is that the film doesn't come out it may still be galling:
examine the outsides and edges of the spool flanges. If they are rough
and worn then the flange is rubbing against the top and bottom caps
and binding.

In any case, if the cassette acts up I would recommend chucking it. The
cost of a cassette is trivial Vs the cost of the film and processing and
the effort of taking the pictures.

And as Mike stated, dirt gets caught in the felt and scratches the film
with too much cassette re-use.

Leica and Nikon made cassettes with trap doors. Locking the back latch
on the camera would open up the cassette. This feature is on the F & F2 but
not of the F3-F6, and is on the M3 and most likely all the early M's
but for sure not on the M5. I think it is also on the I/II/III series Leicas
and their clones - Fed/Zorki/Nicca...

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm

I have to admit to discarding the cassettes while they're still usable.
My biggest fear is that a piece of grit will get into the light seal and
gouge the emulsion along the length of the film or that the cap will come
off. In either case by the time the cassette actually fails it's to late.

For me the biggest form of "wearout" failure I've had is that the cap won't
stay on. I have a few that had problems with sticking.


Alan Smithee wrote:
: I've had the same batch for a couple of years. They all get used in
: rotation. Is sticking the number one cause of plastic cassette failure?


: "Frank Pittel" wrote in message
: ...
: Alan Smithee wrote:
: : I use the plastic film cassettes for reloading. Lately, after reloading
: : they're sticking. I loosen the cap a bit and they spin quickly once the
: : tension is off. It's like I'm tightening the cap too much. But this was
: : never a problem in the past. Does the cap tend to "work in" after many
: : reloads with this type of cassette? I've tried cleaning the surfaces
: with
: : isopropanol and it makes no difference. Should I try "oiling" them? Is
: it
: : just time to throw them out? Thx.
:
: How long have you been using the cassettes. While I prefer the plastic to
: the
: metal one the plastic ones don't last very long.
:
: --
:
:
:
:
: -------------------
: Keep working millions on welfare depend on you



--




-------------------
Keep working millions on welfare depend on you

I think you had it right the first time. Galling. I can see the pattern worn
into both surfaces. Initially I thought it had to be the felt on the slot
grabbing but after testing a dummy roll I ruled that out. I never knew about
that trap door thing existed on the Leicas and the Nikons. I'll have to
check this out on my M3. Can you still buy these types of cassettes?


"Nicholas O. Lindan" wrote in message
ink.net...
"Alan Smithee" wrote

I use the plastic film cassettes for reloading. Lately, after reloading
they're sticking. I loosen the cap a bit and they spin quickly once the
tension is off.

Ah, I may have read this wrong. I have had trouble with the screw on
plastic caps sticking and projected my experience.

If the problem is that the film doesn't come out it may still be galling:
examine the outsides and edges of the spool flanges. If they are rough
and worn then the flange is rubbing against the top and bottom caps
and binding.

In any case, if the cassette acts up I would recommend chucking it. The
cost of a cassette is trivial Vs the cost of the film and processing and
the effort of taking the pictures.

And as Mike stated, dirt gets caught in the felt and scratches the film
with too much cassette re-use.

Leica and Nikon made cassettes with trap doors. Locking the back latch
on the camera would open up the cassette. This feature is on the F & F2
but
not of the F3-F6, and is on the M3 and most likely all the early M's
but for sure not on the M5. I think it is also on the I/II/III series
Leicas
and their clones - Fed/Zorki/Nicca...

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm