From: "Barry L. Ornitz" <ornitz@tricon.net>
Subject: Re: Storing Radios and Components
Date: Jun 12 1997
Newsgroups: rec.antiques.radio+phono

Phil Bolyn <pcb1@trpo3.tr.unisys.com> wrote in article
<339F1274.1B0D@trpo3.tr.unisys.com>...
> I am seeking advice on practical ways to protect stored radios and
> components from dust and moisture damage. My workshop and storage
> area is part of my basement. It gets somewhat damp (high
> humidity) during the summer months.

This is an interesting problem.  Moisture is damaging to most components
but is absolutely necessary for electrolytic capacitors.  These are
typically made with a paste electrolyte which must be damp for them to
function.  It was common to add ethylene glycol and inorganic salts to the
electrolyte (normally boric acid) to absorb moisture from the air and
maintain the electrolyte at a particular humidity level.

> Is it OK to store radios in plastic trash bags? Is it possible
> for the plastic bag material to interact in a damaging way with
> wood or plastic cabinets over a long period of time?

Absolutely do NOT use vinyl plastics (plasticized polyvinyl chloride).  The
plasticizer will leach from them over time and damage what is stored
inside.  Polyethylene trash bags generally contain no plasticizer so they
are safe.  Air and moisture WILL diffuse through them slowly.  Metal foil
is pretty impermeable if you want to use it between layers of polyethylene.

However, particularly with OLD radios, some of the internal plastic parts
may be cellulose ester based.  This includes celluloid (cellulose nitrate
plasticized with camphor), cellulose acetate, and mixed esters like
cellulose acetate-butyrate.
These materials will eventually break down releasing the corresponding
acid.  This acid will catalyze the further decomposition and soon you will
have nothing but a sticky, corrosive mess.  Free air flow over these
plastics will remove most of the acid released, but by sealing them in an
airtight container you will almost guarantee that once the decomposition
starts, it will continue quickly until everything is ruined.

There are special test papers that can be packed next to these plastics
that will change color and give early warning, but you have to check these
frequently.  If you should note any tendency for old plastics to get sticky
or smell acrid or acidic, you should remove them immediately and soak them
in a dilute solution of baking soda for several hours to neutralize the
acid.  If these plastic parts are dials and such, be careful as washing is
likely to remove the markings.

It is unfortunate that many clear dials and dial covers were made of
cellulose acetate as late as WWII.  This was often done in the interest of
cost savings and the poor availability of better materials during war
shortages.

> Is a dessicant required? If so, where do I get it locally?

Dessicants are rarely required if you can guarantee that the storage
location remains at a reasonably constant temperature.  The worst thing is
for warm, moist air to contact cold stored items.  Temperature changes will
cause even the best wrapped packages to "breathe."  

	73,  Dr. Barry L. Ornitz  WA4VZQ  ornitz@tricon.net