Foam for lens case

[NW2Wheeler]

Good Afternoon Forum members,
I am thinking about building some custom lens cases for my 4x5 lenses 90-250mm (mostly Fujinon CM W series).
It seemed like a reasonable design problem until I started thinking about which kind of foam to use for cushioning.

There is a multiplicity of different foam types, open cell / closed cell / polyethylene / polyurethane / polyester / et cetera.
It would at first blush, seem that closed cell would be the obvious choice. Is this the correct assumption?

One concern that would be problematical is outgassing - Does anyone have any wisdom in this area they would care to share?

Any Spec callout (Mil or otherwise) that I can use to differentiate between the choices?

Thanks for your time and experience.

[Bob Salomon]

There is another major problem. Foam that deteriorates and lets very small pieces migrate into whatever is stored in it.

You can see this in some older camera cases. Like old Fiberbuilt or Halliburtons.

[Dave Dawson]

Assuming your lenses are mounted on lens boards....Why would you want to surround them in foam?

Cheers Dave

[Jac@stafford.net]

Cotton batting is best.

[LabRat]

Foam is going to be a problem sooner or later...

The last case I put together had slotted holders to support lensboards, cut from wood strips...

Steve K

[Dave Dawson]

Foam is going to be a problem sooner or later...

The last case I put together had slotted holders to support lensboards, cut from wood strips...

Steve K

Exactly !

Cheers Dave

[John Kasaian]

It's a lot of fun emptying those purple bags which bottles of Crown Whisky comes in, which can then be used to hold lenses

[Nodda Duma]

Outgassing is going to be a problem for long term storage with foam. The suggestion of slots in a wooden case is best. Line the slots with felt and ensure the lens can’t jostle around when the lid is closed. This is how optical instruments are packaged in the industry

[HMG]

It's a lot of fun emptying those purple bags which bottles of Crown Whisky comes in, which can then be used to hold lenses

Or, for the teetotaler, there are lens wraps. But I'd be leery of any of those fabrics in contact with the glass.

[Bernice Loui]

Big NO on any foam used for precision optics. Foam degrades and outgassed with corrosives chemicals. Degrading foam does an excellent job over time to slowly digest the item stored in a foam padded container. Hard woods like Popular, Birch, Spruce ply and similar with felt is commonly used as padding-contact material for optical lenses or other high precision devices.

Take a hint from what Eastman Kodak once did with packaging their Ektar lenses, they were shipped and stored in very high quality wood boxes lined with felt. These Kodak Ektar boxes were excellent high quality items all their own. Speaks volumes about what Kodak Ektar lenses once were.


Bernice