Treating rubberized cloth shutter curtains ?

[Spyderman]

Hi,

I was just thinking about some treatment to keep the rubberized cloth focal plane shutter curtains in good condition. It's natural that the rubber ages, so why not try to keep them in good condition ?

I've got a couple of "parts" FED-2's with the curtains dry and with many cracks, then I've got a couple good FSU Zorkis and FEDs, and just recently I bought a Zorki-1 with quite good curtains, but there are a couple of small cracks...

So, one question is how to avoid cracking of the curtains ? and another is how to repair those cracks when they appear ? (other than to replace whole shutter curtains)

I was thinking about applying glycerine as a general rubber treatment... I even applied some of it on curtains of some of my cameras, but I don't know if it helped at all... But certainly it doesn't seem to hurt either.

What do you think ?

 

[ZorkiKat]

Ondrej

Some have reported using "Armor All" as a rejuvenating cream for vulcanised cloth shutters. Armor All is a prepartion for preserving rubber and vinyl based surfaces, so it may work for some types of shutter blind coatings.

Note though that not all shutter blind coatings are made equal, so treatment for one make may not work for others.

The deterioration of rubberised coatings is inevitable. Climate plays a role in the rate that this happens. The coatings dry, lose their suppleness, and crack and flake as they age.

Cracking curtains have very little chance of being useful for long if they are just patched.
Patching cracks (as opposed with patching small pinholes - these are entirely different) is at best a stop-gap measure. It's a temporary remedy done to make the shutter useable at least until its blinds can be replaced. When the vulcanised coating cracks, it means that the shutter blinds have reached the end of their useful lives.

Pinholes are different. Having them does not really mean that the rubber coatings are dying. Patching one or more of these tiny holes is a sound repair procedure. I use rubberised textile paint (ordinary black textile paint is as good) to patch tiny pinholes.
The paint is applied as tiny dabs with a toothpick and then 'smudged' flat using the finger. Textile paint often dries quickly, so the shutter can be used about an hour after application of the patches.

Glycerine may not be a good material to put on your curtains. The hygroscopic nature of glycerine will not be good for the shutter blinds, or the camera's insides for that matter.

Jay

 

[wolves3012]

Ondrej,

Both the rubber coating and the cloth of the curtains will become brittle with age - glycerine will do nothing to help this and, as Jay says, will attract moisture that may do more harm than good. There's little you can do but replace ageing curtains. As for keeping them in best condition, store the camera away from strong chemicals and in a not-too-damp place. More than that there isn't a lot you can do. They will age and you can only try and minimise that.

 

[oscroft]

I've used acrylic black paint to patch small pinholes - you can get it from art supply stores. it's flexible enough to work, and dries fairly quickly. But I agree that trying to patch up cracks is at best an emergency measure.

 

[Spyderman]

Thanks Jay.

In case of my Zorki - it's just a part of the curtain that shows some cracks. I examined the whole curtain, but bigger part of it seems to be in good shape - elastic, no signs of drying. I'd like to repair just the part with cracks...

And thanks for the warnong about glycerine. I'll avoid it in the future...

 

[mravigna]

Spiderman, I have repaired the shutter curtains on my Fed 1 with textile paint and a small paint brush. You need to let it dry overnight. I would recommend adding a second coat . Pinholes often appear because of a crack in the rubber. I have also repaired one the shutter curtains in an old Exakta Varex. This one was full of pinholes (hundreds I would say). The rubber viewed from the lens mount side was full of cracks letting the light run through the cloth curtain. I painted the cloth side (back side) with textile paint (several coats) and this seems to have worked. I also painted the cracks on the rubber side (inside mirror box). I dont use this camera very much and changing a curtain is simply not worth the expense. The textile paint works fine and seems to last long enough, although would probably not if the camera was being used consistently over several years.

 

[Rob-F]

When not in use, store the camera in a cool place, with normal humidity. The environment that is comfortable for you is good for your shutter.

 

[mravigna]

I also think that exposure to light will shorten the life of a rubberized curtain. The Exakta that I was referring to in my last note has one cracked shutter curtain (the other one is perfect). The cracked curtain is the one exposed to light (once the shutter is fired) through the lens. I think that this camera was left with its lens on without a lens cap in a display cabinet for many years. These cameras are very pretty and often displayed like this in special glassed cabinets. I purchased this camera on Ebay and the lens was filthy covered with encrusted dust on it's outer surface. This is why I think that it was left exposed to light for several years. Keep a lens cap on your camera and this should help protect the curtains against UV rays.

 

[giovatony]

Why not consider the black butyl rubber repair adhesive that comes in a squeeze tube?
It`s flexible and should be suited for larger cracks and holes.

 

[Murray Kelly]

I have a Thornton-Pickard shutter here from my Great Uncle - it is over 100 yo. What kind of cloth is recommended for a rebuild of one of these shutters? It is stuck hard in the rolled up position, but with the knowledge and encouragement here I feel more like tackle-ing the problem myself rather than see it go to waste.

The rest of the camera is in need of attention too, but the shutter is the biggest problem at the moment.

Murray

 

[ZorkiKat]

One factor to consider when painting over cracks on shutters is the extra layers which these patching material will put on the shutter cloth. An additional layer painted over will make the cloth blind thicker and heavier. The cracks to begin with are often places on the cloth blind which have become slightly thicker because of some separation between the cloth base and the vulcanising material.

Not only that, painting over some places will also mean that the patched blind will become thicker only in some places than in others.

A patched/painted shutter cloth which has become heavier and thicker in some places will definitely affect the efficiency of the shutter. That would mean uneven travel, or the necessity to increase the tensioning which in turn leads to more stress on the winding and more noise during firing.

Jay

 

[giovatony]

OK, I guess it would be senseless to argue or not consider ZorkiKat`s remarks . They make good sense .
However it`s also hard to dismiss the fact that a spot of flexible black coating thinly applied should not cause damage or should it noticeably effect shutter operation. If the normal operation of a camera is impeded it should be a clear signal that the repair was not done correctly. Probably not dry or applied in a too thick or heavy manner.
These simple repairs do work and have obviously proven to be a rather cost effective means for many. Done properly it should significantly extend the usefulness of a camera without having to assume the cost of curtain replacement , possibly worth more than the cost of the camera itself.

I`m in the middle of testing a high quality black acrylic artist paint (in a squeeze tube) on a peice of paper and woven cloth . What I`m finding is that after drying this stuff applied in a thin coat stays very flexible. I`d be quite amazed if it didn`t prove to be an excellent solution to a simple problem.
John

 

[Spyderman]

Let us know your results John. I'm very curious...

Interesting thing is, that often only a spot of the curtain is dry ant the rest is fine still flexible without any signs of drying I've got one curtain like that - only a circle with 1cm diameter is dry and cracking. This is out of camera at the moment, so I'll try to remove the layer of rubber from the dry section and try to replace it with some suitable paint...

 

[giovatony]

It seems the curtain material used in most FSU`s was pretty good material.
It has lasted well and in all my cameras it appears to be fine.
But I have one with a thinly worn spot 6 mm round and I have coated it with the Acrylic black paint and a small flat artist brush to spread it thinly and to blend it in to the surrounding area.
It remains quite pliable after drying.
This stuff is sold in craft shops and comes in a squeeze tube and seems to be a perfect consistancy.

 

[mravigna]

My response is to Zorkikats comments on how this might affect shutter response. I have read this elsewhere but based on my own experience, applying thin coats of textile paint will not affect the shutter response in such a significant way. Applying thick coats of rubber would likely set the shutter off. Also Giovatony mentioned something about using black butyl rubber.
I am not sure where this can be found. What would be a company name for this kind of product?

 

[ZorkiKat]

Cracks vs Pinholes

Cracks vs Pinholes

If it's just a pinhole or two or three that is the issue, then patching over the spot is no problem at all- my first response (#2) did say that pinholes are another matter. I even stated the method and material I use for patching them.

However, it is painting over serious cracking which is what I'm against. I've seen serious cracks -not pinholes- which run almost the width of the blind, and cause the vulcanising to separate and fall off the cloth. Painting over these isn't a good idea. I've done it before when I did not have the ability to do any better. But what came next were more cracks, subsequently followed by more painting over. At the end, new cracks eventually formed (perhaps because of stress caused by the new layers of paint, giving the old shutter blind various degrees of flexibility all over its surface). Once a shutter blind forms a crack (note Ondrej mentioned "cracks" first before pinholes- and these are two different things), the only way to go is replacement.

add: Shutter function is indeed affected by big 'patch jobs'. I've had a few Zorki and FED, as well as Zenit whose shutters had cracks which were patched with some material and have become sluggish and heavy. They fired noisily and often rougher than the other specimens of similar cameras. Replacing the shutter blinds more than significantly improved these cameras in terms of lighter winding and quieter firing.

 

[giovatony]

My response is to Zorkikats comments on how this might affect shutter response. I have read this elsewhere but based on my own experience, applying thin coats of textile paint will not affect the shutter response in such a significant way. Applying thick coats of rubber would likely set the shutter off. Also Giovatony mentioned something about using black butyl rubber.
I am not sure where this can be found. What would be a company name for this kind of product?

One brand is Locktite # 5368 a type of black flexible adhesive and i would imagine it to be very similar to black silicone sealant / adhesive found in automotive stores.
I`ve ran across references to a variation having butyl rubber incorporated nto it. I know for sure they make a black butyl rubber sealant adhesive used for calking purposes too. Tis can be found in home improvement stores.

As mentioned before it really would have to be applied sparingly and thin or it might interfere with curtain operation .
John