[Milsurplus] Plastics turning to cheesecake

[Barry Hauser]

Hi Hue & list ..

I doubt if the condition of the cable is the same as that old foam padding 
that turns to gooey "cheesecake" as you put it -- I've seen a lot of that 
stuff.

More likely, the cable was coated with something and/or the oils from the 
rubber, neoprene or whatever have leached out to the surface.  I'm assuming 
this is a military radio cable, most of which were made of very durable and 
restorable stuff, in my experience.

Avoid using (the wrong) solvent, detergent or 409 type cleaners as this will 
dry out the rubber and cause it to crack prematurely.  The best stuff to use 
is CaiKleen from Caig -- the people who make DeOxit.  I have also found a 
cheaper rubber cleaner/rejuvenator for about $3, but can't remember the name 
offhand.  Both of them have a very strong orangy/citrus odor.

You wet a rag or paper towel with a moderate amount of CaiKleen and wipe 
down the cable with it.  Results may be alarming at first as a lot of black 
will come off on the rag.  It will seem as if you're dissolving the thing. 
It will probably take several go-rounds with fresh toweling until the cable 
is clean.  The black will continue to come off, so don't use that as a 
guide.  Did one cable some time ago which I was sure I had ruined with the 
stuff -- it reacted with a case of the chicken pox -- all puffed up and 
uneven looking.  I stopped and let it set.  About a half hour later, it 
looked like new as the rubber recovered and shrunk back.

Apparently Caikleen does two things -- dissolves off dirt, grease and old 
dead rubber -- and adds back some oil or whatever.  It is excellent for 
cleaning and restoring dirty old rubber test leads.  Get's the gunk off, a 
bit of the dried out rubber surface.  The red lead is red again and the 
leads become flexible and drape the way they're supposed two.  I bought a 
half-pint can about 4 years ago and still have about half left.  Have also 
used it on more modern cables (PVC/vinyl, etc.), rubber feet and other 
rubber parts with good results.

The stuff reeks like the orange grove got hit with napalm, but it works like 
a charm.  You'll find yourself looking all around for old rubber things to 
use it on.

I've seen a lot of examples of plastic cases that have become "engraved" by 
cords -- sometimes obviously wrapped around them.  That's probably some 
other chemical reaction -- possibly aided by heat.

Barry



Hue wrote:

> The other day i unwrapped a power supply cable for a radio, manufactured 
> and wrapped in
> 1945. The surface of the cable was very sticky. Altho i will indeed try to 
> clean it, i suspect
> it is in the process of becoming sticky black cheesecake, like equipment 
> feet, handles,
> some cabling, and shock-resistant padding in shipping trunks on other 
> equipment older than
> 40 years or so.
> I wonder: what is going on here. Is the "plasticizer" which lends 
> flexibility or some softness
> to plastics based materials, now migrating to the surface? Or?
> Will all plastics based components meet this fate - the still solid ones 
> just waiting their turn?
> Or is there a reason some plastics  components will  "melt" while some 
> others will not?
> I think the "melt" syndrome is similar to the situation seen in 
> collectible transistor radios
> where a headphone cord stored in the same box "burns" lines into the 
> radio's case.
> -Hue Miller  KA7LXY / Newport, Oregon, USA, Oregon's scenic Pacific coast
> ______________________________________________________________