---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 01/25/19: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:04 AM - Re: Re: When / where to use dielectric grease? (Robert L. Nuckolls, III) 2. 07:42 PM - Adjustable pot prohibited ? (GTH) 3. 10:46 PM - Re: Re: When / where to use dielectric grease? (rayj) ________________________________ Message 1 _____________________________________ Time: 10:04:20 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: When / where to use dielectric grease? At 05:26 AM 1/24/2019, you wrote: > >There's a lot of chatter about the use of >dielectric grease. Permeate suggests that >Dielectric Tune-Up Grease is a good barrier to >oxidation at plugs, connectors and >terminals. There are some online comments at >forums that say not to place dielectric grease on connector pins. > >I've gone to the Permeate site, and the information is vague: > >"Protects electrical connections and wiring from >salt, dirt and corrosion. Extends the life of >bulb sockets. Prevents voltage leakage around >any electrical connection. Also prevents spark >plugs from fusing to boots. Required for modern high energy ignition systems." > >Directions for Connectors: 1. Make sure ignition >system is off. 2. Clean surface with Permeate >Contact Cleaner. 3. Coat both parts of terminal >contact with Dielectric Grease. 4. Reassemble, >maintaining metal-to-metal contact. > >In the PDF, Permatex cites uses for the Permatex Dielectric Tune-Up Grease: > >TYPICAL APPLICATIONS > >=A2 Spark plug boots > >=A2 Distributor cap nipples > >=A2 Battery terminals > >=A2 Ignition coil connectors > >=A2 Headlamp connectors > >=A2 Trailer electrical connectors Dielectric greases and coatings are proven prophylactics that ward off the effects of adverse environments for which the potential 'victim' is ill-equipped to manage on its own. Borrowing from the assertions of another competent observer of really big numbers, let us consider what must be 'billions and billions' of mated conductors in connectors that have performed over the LIFETIMES of the target technology with no 'extra' protection squeezed out of a tube or brushed on from a bottle. Does this mean that such products have no useful place? Not at all. My FIRST experience with dielectric grease moisture protection was 175' up on a tower where the boss told me that filling the mated coax connectors with DC4 before assembly had a demonstrated value for shielding connectors exposed to Kansas climate way up in the air. Over the years, I have had occasion to open factory assembled connectors that were obviously offered the benefits of protection above and beyond those offered by the enclosure. This includes lamp sockets on tail and back-up lights, marker lights and yes, trailer connectors. These instances were most common on fixtures especially exposed to splash or run-down. When refurbishing equipment that succumbed to contamination induced corrosion, the 'rule of thumb' called for protecting the replacement hardware with a good dielectric grease. But it was also a good idea to see if some gasket had failed allowing ingress of moisture. Emacs! In years since, designers for electrical connectors improved designs to improve performance in harsh environments. The moisture seal bellows on this connector is one example. Emacs! It's been a long time since I've opened a connector that contained any previously applied protection against moisture. It stands to reason that suppliers of such products want to sell as much as the market will purchase. The marketing problem is that it's seldom necessary/beneficial. The only time I've used the stuff is to provide an extra layer of protection for components that replaced victims of moisture damage . . . or selected instances of extra-ordinary risk . . . like difficult-to-access 175' up on a tower. The short story is that these products are best applied during replacement of parts that have succumbed to moisture effects. But when such damage is discovered, be sure to evaluate the circumstances of the failure. Was the connector a poor choice to begin with? Was it subjected to environmental stresses outside original design goals? Does a sealing feature of the enclosure need refurbishment? I have a 4oz tube of DC4 that is probably 40 years old and barely shows signs of having been squeezed. Dielectric grease is a band-aid on a marginal design. Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:42:33 PM PST US From: GTH Subject: AeroElectric-List: Adjustable pot prohibited ? Hello all, In the past few months I designed for some building buddies a small electronic device to close a relay when below a certain voltage. It includes a small multi turn potentiometer to adjust the 13.5 V or else set point. The device is currently under test. My intention was, once satisfied with the operation, to seal the potentiometer with a dab of varnish. But a friend just tells me that in aviation adjustable pots are prohibited, and that once adjusted, we should normally replace the potentiometer with fixed resistors or adequate value. Does anyone have further information about this rule ? Thanks, -- Best regards, Gilles http://contrails.free.fr ________________________________ Message 3 _____________________________________ Time: 10:46:54 PM PST US Subject: Re: AeroElectric-List: Re: When / where to use dielectric grease? From: rayj I can only comment from my experience on boats and docks. I have seen less corrosion problems on connections treated with dielectric grease. The difference can be seen in a matter of a couple of seasons, especially on ones that are removed and replaced frequently, such as removable anchor lights and cigar lighter type connectors. Admitted these are not high buck sealed connections designed for the harsh maritime environment, but using grease changes them from problematic designs to being reliable connectors. Raymond Julian Kettle River, MN The things we admire in men, kindness and generosity, openness, honesty, understanding and feeling are the concomitants of failure in our system. And those traits we detest, sharpness, greed, acquisitiveness, meanness, egotism and self-interest are the traits of success. And while men admire the quality of the first they love the produce of the second. -John Steinbeck, novelist, Nobel laureate (1902-1968) On 1/25/19 12:03 PM, Robert L. Nuckolls, III wrote: > At 05:26 AM 1/24/2019, you wrote: >> >> There's a lot of chatter about the use of dielectric grease. Permeate >> suggests that Dielectric Tune-Up Grease is a good barrier to oxidation >> at plugs, connectors and terminals. There are some online comments at >> forums that say not to place dielectric grease on connector pins. >> >> I've gone to the Permeate site, and the information is vague: >> >> "Protects electrical connections and wiring from salt, dirt and >> corrosion. Extends the life of bulb sockets. Prevents voltage leakage >> around any electrical connection. Also prevents spark plugs from >> fusing to boots. Required for modern high energy ignition systems." >> >> Directions for Connectors: 1. Make sure ignition system is off. 2. >> Clean surface with Permeate Contact Cleaner. 3. Coat both parts of >> terminal contact with Dielectric Grease. 4. Reassemble, maintaining >> metal-to-metal contact. >> >> In the PDF, Permatex cites uses for the Permatex Dielectric Tune-Up >> Grease: >> >> TYPICAL APPLICATIONS >> >> Spark plug boots >> >> Distributor cap nipples >> >> Battery terminals >> >> Ignition coil connectors >> >> Headlamp connectors >> >> Trailer electrical connectors > > Dielectric greases and coatings are proven prophylactics > that ward off the effects of adverse environments for > which the potential 'victim' is ill-equipped to > manage on its own. > > Borrowing from the assertions of another competent > observer of really big numbers, let us consider what > must be 'billions and billions' of mated conductors > in connectors that have performed over the LIFETIMES > of the target technology with no 'extra' protection > squeezed out of a tube or brushed on from a bottle. > > Does this mean that such products have no useful > place? Not at all. My FIRST experience with dielectric > grease moisture protection was 175' up on > a tower where the boss told me that filling the > mated coax connectors with DC4 before assembly > had a demonstrated value for shielding connectors > exposed to Kansas climate way up in the air. > > Over the years, I have had occasion to open factory > assembled connectors that were obviously offered > the benefits of protection above and beyond those > offered by the enclosure. This includes lamp sockets > on tail and back-up lights, marker lights and > yes, trailer connectors. > > These instances were most common on fixtures > especially exposed to splash or run-down. When > refurbishing equipment that succumbed to > contamination induced corrosion, the > 'rule of thumb' called for protecting > the replacement hardware with a good > dielectric grease. But it was also a good > idea to see if some gasket had failed > allowing ingress of moisture. > > Emacs! > > In years since, designers for electrical > connectors improved designs to improve > performance in harsh environments. > The moisture seal bellows on this > connector is one example. > > Emacs! > > It's been a long time since I've opened > a connector that contained any previously > applied protection against moisture. > > It stands to reason that suppliers of > such products want to sell as much as > the market will purchase. The marketing > problem is that it's seldom necessary/beneficial. > > The only time I've used the stuff is > to provide an extra layer of protection > for components that replaced victims > of moisture damage . . . or selected > instances of extra-ordinary risk . . . > like difficult-to-access 175' up on a tower. > > The short story is that these products > are best applied during replacement > of parts that have succumbed to moisture > effects. But when such damage is > discovered, be sure to evaluate > the circumstances of the failure. > Was the connector a poor choice to > begin with? Was it subjected to > environmental stresses outside original > design goals? Does a sealing feature of > the enclosure need refurbishment? > > I have a 4oz tube of DC4 that is probably > 40 years old and barely shows signs of having > been squeezed. Dielectric grease is > a band-aid on a marginal design. > > Bob . . . > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.