Packard Shutter mystery! Please help if you can...

[Dustyman]

Greetings.

On an 8x10 Century Master Studio camera I have a large Packard shutter (8x8" with 4-1/2" opening) that has separate timed exposure and instantaneous pistons utilizing two separate air bulbs.

If you are reading this then you probably know that, regardless of which piston you expose with, one must use the timed exposure option to "lock" open the shutter to focus. The problem is that it is way too sensitive, making it very difficult to get the shutter to stay in the open position. It takes quite a few super gentle attempts with the bulb to get the shutter remain open. Then, once it is finally "locked" open, even a very slight vibration of the camera causes it to close again. This is extremely frustrating when doing portraiture.

Usually with these old shutters the opposite is the problem. They would get stuck open or do not smoothly close. In this case, however, it does't want to remain open. It's as if there's not enough friction on the piston tube itself.

I have lots of experience with using Packards. I have several, used them for years. I even have another one, just like this one, mounted on my Deardorff 8x10 Portrait camera. All the others work fine. No problem locking the shutter in the open position. It's just this one, on the Century, that is too sensitive and shuts down too easily.

Suggestions? Anybody experience this same issue? I would love to hear what you might suggest I try.

[cdholden]

I'm not that familiar with the insides, but take 2 apart and compare this problematic one with a good one.

[mdarnton]

I can think of a lot of ways to increase the friction of the cylinder so it didn't easily drop back down. Something reversible, like pulling the piston out as far as it goes and rubbing some candle wax on it, but not smoothing it out, or building a pile of adhesive back felt next to it so that the rising piston would rub against the felt. I don't think they're intended to be oiled, so even a drop of oil might increase friction enough to make the piston stick. What I would not do is anything permanent, like scoring the piston.

[Jon Shiu]

Maybe try it sideways?

[Tin Can]

I have the same shutter. I suggest you do not oil anything, these must dry as can be. I would take it apart and see if any leafs look odd. Clean out the dust! and rust.

I have seen some WWII mods, where they paper lined the metal insides, for whatever reason. Perhaps silence, perhaps to make it work better.

Mine slips shut also, but lately it likes to just stay closed until I reach in side and wiggle both pistons. Jim Galli has said and I believe him, the double piston models are not as good as single piston.

When you fix that one I have a 5" with 4 leaves that is immaculate and doesn't work...different design that now another member here has to try his hand at it...last I heard he gave up too.

Last minute thought. These are designed to work 'upright', maybe turn it 90 degrees. I know they don't like being upside down.

[Tin Can]

Maybe try it sideways?

Ha, just what i thought!

Worth a try.

[Dustyman]

Thanks all. Turning on its side does keep it open, but it's sometimes finicky about closing, requiring more reverse suction than normal. It's definitely an option though, should other ideas not work.
I like the idea of building up felt for the side of the piston to gently rub against, an idea that crossed my mind before I posted the question. I'll probably give that a try before adding stuff, i.e. wax, to the piston itself. My local Home Depot has adhesive backed felt. I'll let you know how successful it is.

[Dustyman]

Just a quick followup. The felt option was 100% perfect. Just 2 small round self adhesive pads on either side of the piston groove did the trick. The shutter stays firmly open with a single squeeze. Closes with normal reverse suction. Works like a dream. Thanks to all.

[Dustyman]

Just noticed how phallic these pictures are. Oh well, whattaya gonna do.

[Tin Can]

Interesting. I will try that.

Is the felt polyester, which may produce less dust than wool, cotton or natural felt?

I may try soft Velcro dots, just because I have them.