"Don Fearn" wrote...
Post by Don FearnPost by Dave H."Blabber" wrote...
Post by BlabberAnyone have any ideas on how to remove silicon dielectric grease from
small
Post by Blabbermultipin bike connectors? I'm looking for something that I can soak the
connector in or spray on (since the pins are too small to clean directly).
Thanks for any advice.
Whatever you use, get that silicone crap away from anything electrical!
Silicones subject to arcing decompose, leaving a residue of silica (yep,
sand, like on sandpaper) - if this is between mating surfaces or contacts it
wears away any protective plating or contact material, and also embeds
itself in the base metal so that it can carry on wearing away (for instance)
your nice expensive non-repairable switchgear...
You can buy mineral greases designed for electrical contacts which don't
cause this problem - the yellow or red stuff sold for battery terminals is
pretty good, waterproof and corrosion inhibiting.
What are you babbling about? Silicone Dielectric Grease is exactly
what you WANT on electrical connections that are subject to the
elements. Yeah, like connections on motorcycles. See
http://tds.loctite.com/tds5/docs/DIEG-EN.pdf for more details . . . .
Hi Don, I know it's sold as such, but this is a known problem with silicones
in electrical contact applications, refs here:
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&arnumber=1518216&isnumber
=32504
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&arnumber=1135411&isnumber
=25247
http://www.e-driveonline.com/images/DowCorning.pdf
http://www.echeloninc.com/contactlubrication.htm (the "silicone
contamination" bit)
There are a number of advisories (particularly among the military and
aerospace fields) regarding avoidance of silicones in electrical contact
assemblies - this issue has only been known since the late 80's / early 90's
but there are a number of verified and reviewed studies that have been
carried out that all contra-indicate its use where moving or arcing contacts
are present.
A nice quote re inter-board contacts (from a computer engineer)
"Another contaminant that causes havoc when deposited within connections is
silicone. Furniture and floor polishes are prime culprits in the spread of
silicone oligomer which can contaminate connections a considerable distance
from the source application. Fretting or arcing converts the oligomer into
hard crystals of abrasive compounds, e.g. silicone carbide, which cause a
loss of conductivity and exacerbate the wear in the contacts.
Many sprays sold for electrical use contain silicone oils which, although
they may provide lubrication and repel water, do more harm than good in this
context."
In my last job (maintaining a military satellite ground-station) and my
current job (maintaining internet backbone and similar hardware) there are
strict "no silicones" policies due to this issue (afraid I can't remember
the DEFSTAN number...), to the extent that a USAF guy I knew and worked with
was banned from maintenance activities and sent for retraining for using
silicone grease to seal external connectors (just like those multipins on
our bikes). I've had personal experience of a set of bike switchgear ruined
by silicone use, and seen the results of contamination in a variety of other
contact assemblies (I've been maintaining a variety of electrical and
electronic kit for 30 years, and it *only happens with silicones*) and I
would never let the stuff near anything I might have to repair in the
future!
Hope that helps,
Dave H. (The engineer formerly known as Homeless)