On Thu, 27 Sep 2012 14:32:30 -0700, BeeJ wrote:
I have some rubber components that need protection.
Previously these rubber parts deteriorated probably due to crap in the
air (all I can figure since that is all the were exposed to over years
of sitting untouched). These components are used for light blocking
like on a camera lens and have no mechanical interfaces other than
mounting.
So would using pure silicone spray be best or what?
Spray and wipe off excess leaving a very think film or would it soak
in?
Suggstions please.
The Smithsonian uses cold storage:
http://www.si.edu/mci/english/research/past_projects/rubber_deterioration.html
How to store rubber and plastic parts:
http://www.epm.com/storage.htm
I would not be so sure about your analysis. I have some instruments
with rubber feet that have turned into a sticky gooey yucky
semi-liquid mess. The problem is that out of 4 feet, only one has
deteriorated. It was something in the environment, why didn't it
attack only one rubber foot? I've seen similar situations with rubber
idlers on tape and VCR recorders. Some of these have never seen the
light of day, much less a UV lamp. My success with coating the rubber
with something that blocks UV has been dismal. I use clear acrylic
(Krylon) for this purpose to prevent deterioration of vinyl tape on
outdoor antenna installations. It works just fine for this purpose,
but not for protecting rubber. My conclusion is that UV has nothing
to do with the rubber deterioration.
Another example is an Alienware (now Dell) laptop with a spray painted
rubberized cover. The entire rubberized area is becoming sticky and
will soon turn to goo. This includes areas which are NOT exposed to
UV. If it were chemicals delivered from the users hands, it would be
localized to areas of contact. That's not the situation as the entire
surface is turning to goo. However, it might be an aromatic delivery
mechanism.
Also note that when rubber turns to sticky goo, it does so over the
entire volume of the rubber part and not just on the surface. If it
were a chemical or optical attack, it would start at the surface, and
be largely unaffected towards the interior. This is not the case,
which leads me to suspect that it is NOT caused by an external attack.
I don't know exactly what causes the problem. My best guess(tm) is
that the problem is in the manufacture of the rubber parts and paints.
There seems to be a time delay involved, where everything is fine
until some reaction occurs, causing instant self-destruction. Near as
I can tell, what happens is that the rubber breaks cross links and
returns to the petroleum based primordial tar from which it was
originally derived.
This article:
http://www.cci-icc.gc.ca/publications/notes/15-1-eng.aspx
suggests that plastic and rubber continuously deteriorates. The
deterioration can be accelerated by multiple sources.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558