[time-nuts] OT: Packing and shipping of test equipment

[J. Forster]

I avoid styrofoam insulation because:

It is too rigid and therefore transmits shocks to the object.
Once crushed, it provides no further protecrion.

-John

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> Jim wrote:
>
>>As you can imagine, it turns out that foam can be too stiff or too
>>soft, and that the appropriate foam density and thickness is
>>dependent on both the mass of the thing being supported and the
>>expected loading.
>
> You also need to pay attantion to what parts of the item can bear how
> much loading, and from which directions -- knobs, connectors, and
> many handles can't bear much, for example -- and design the packaging
> to route loads around these features to other parts of the item that
> can bear them.  That's what all the carefully folded cardboard and
> die-cut foam in engineered pakaging do.
>
>>Take home message:  packaging is non trivial. A simple: "pack it in
>>two boxes with X inches of crumpled paper or peanuts" isn't going to
>> work.
>
> There is no substitute for a basic understanding of the physics
> involved and the properties of available packing materials.  The
> mistake I see most often is that the contents of a box are not
> immobilized by the packing.  When the box is in motion and then
> stopped abruptly, the item has a running start to smash into the
> inside of the box and whatever stopped it.  Sometimes there is enough
> packing material to fill the space in the box but it just isn't stiff
> enough (e.g., light open-cell foam), and sometimes there isn't enough
> packing material so there is air space inside the box.  Frequently,
> both.  The buffer material for a 50 to 100 pound item needs to be
> considerably stiffer than most people think.
>
> That said, it's not rocket science.  Large-bubble bubble wrap,
> wrapped TIGHTLY around the item in at least two directions until
> there is at least 4" on all sides of the item, is a very good start
> for anything up to about 100 pounds (6" on all sides is better by the
> time you get to 100 pounds).  You may need to use sheets of styrofoam
> insulation, heavy cardboard, or plywood to make sure loads will not
> bear on fragile parts of the item.  The bubble wrap must be taped up
> very tightly so the wrapped item feels like a monolith bursting at
> the seams, then put into a box rated for the weight of the item.
>
> All internal space in the box must be filled with packing -- the
> bubble wrap, applied as described, will make a rounded shape, so
> peanuts or something else must be used to fill the gaps to the square
> corners of the box (I hate peanuts, so I generally use rolls of
> bubble wrap, pieces of styrofoam building insulation, etc.).
>
> Finally, the entire contents should modestly overfill the box -- you
> should have to compress the packing to get the box shut.  When you
> do, USE TAPE FREELY.  Do not depend on tape-to-box adhesion -- wrap
> wide (at least 2"), strong tape all the way around the box
> (fiberglass filament tape is excellent), lapping the tape over itself
> the entire length of the longest side to form a tape band all the way
> around the box.  Wrap tape all three ways around the box (all three
> axes).  For smaller boxes, you can wrap once per axis, in the middle
> of the box.  For larger boxes, you need to use two or even three of
> these loops per axis, spaced out along the box.
>
> You can also build up most of the buffer with styrofoam building
> insulation, if you prefer.  I still like to use an inch or two (all
> sides) of tightly-wrapped bubble wrap as the innermost layer.
>
> All of this is not exactly free, and takes a bit of time -- I often
> use a whole roll of bubble wrap, sometimes more, and half a roll or
> more of tape, for a benchtop instrument or a boatanchor radio.  Plus
> a good, sturdy box.  But I have never once had an item damaged in
> shipping, since long before there was an eBay.
>
> Best regards,
>
> Charles
>
>
>
>
>
>
>
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