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On Friday, March 12, 2010 9:10 AM, Eisloeffel, Paul wrote:

> I'd line the crates with ethafoam (or styrofoam in a pinch; 
> it's cheaper but less rigid)

Yes.  A material that surrounds the discs and absorbs any
shock is important.


>  and also sandwich each disc between two sheets of ethafoam. 
> 1/2" should do.

Some alternative thoughts on this.  Some mechanical issues 
with glass discs are (1) impact and (2) flexure (others on 
this list have already talked about temperature and humidity).

The crate lining will help protect against impact.  But the 
foam layer between each disc will not prevent flexure, 
particularly if the crate is dropped and there are acceleration 
forces orthogonal to the plane of the disc.

You can better protect against flexing by actually sandwiching 
the discs directly together, while in their base-buffered 
archival sleeves. This creates a rigid structure akin to a 
piece of plywood.  This sandwhich should have as its book 
ends some sort of rigid layer like melamine board.  This can 
then be tied or taped to form a very rigid sandwich so that
the discs do not shift relative to each other.

If you have a mix of glass and aluminum discs, put the glass
in the center of the sandwich with aluminum discs on the
outside.

We like to package 10 discs per sandwich.  This keeps the 
overall weight of the sandwich manageable, and less likely 
to be dropped or mishandled due to its size and weight 
when being packed or unpacked.

These sandwiches can then be put into foam lined crates or
boxes.  The foam should protect the sandwich from every 
direction, both edges and faces.

> So looking at the open crate from the top, from left to right 
> you'd see: crate side, ethafoam, disc, ethafoam, disc. . . 
> until you reach the opposite side of the crate.

See my notes above.  I'm not sure that foam between each disc
is the safest method of transport and storage due to concerns
about disc flexure when the crate is handled roughly.

We've been successful shipping 16-inch glass transcription 
discs in rigid sandwiches cross country as described above,
without a foam layer between each disc.

On Friday, March 12, 2010 9:39 AM, George Brock-Nannestad wrote:

> Going to the media that query (1) was about: the transcription 
> discs, there seems to be 5 plywood crates. These are probably 
> made for the job, and for keeping horizontal. Specifically 
> these I would propose to put in larger, horizontal boxes, with 
> insulating padding all around them. They will take up more 
> space, but temperature changes will be a lot slower and shocks 
> will be partially absorbed.

I really like this suggestion, which in effect treats the 
existing crate as a sandwich.  Each time a glass disc is
handled, there is an opportunity for breakage.  If the 
existing packaging is good for storage, but maybe not 
sufficient for transit, "double boxing" the existing crates
can minimize handling of each disc while improving their
protection during transit.

> If the plywood boxes are not filled and if there is an 
> insufficiency of padding inside the box, putting them on 
> edge will most probably damage the discs even more than 
> keeping them horizontal.

George brings up an excellent point here - at the very least,
take time to open each box and make sure there is no empty
space in the box.  If there is, fill that space uniformly
with padding.  If the padding is bunched up in such a way
that it is applying more force on one face of a disc than
another, there is risk that this non-uniform force will 
crack the glass.  For this reason, we prefer sheet padding.

I've used 1/8" and 1/4" sheets of closed-cell polyethylene 
foam with good results.  It can be purchased in rolls and 
easily cut to fit.  The closed cell foam does not absorb 
water, resists mold and mildew, provides shock absorbption, 
it's lightweight, and is a modest temperature insulator.


Eric Jacobs

The Audio Archive, Inc.
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Disc and Tape Audio Transfer Services and Preservation Consulting