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MG TD TF 1500 - Conductive Material on Painted Surfaces

I'm trying to find the name of the material in a tube that is used to both protect the normally painted tub surface from rusting & at the same time permit maximum electrical conductivity. I'm about to connect the earthed terminal to the painted battery box & the earthing strap from the chassis to the engine. There are a few other places where I could also use it e.g. the harness earth at the horn & at the fuel sender. I want to ensure a really good electrical connection & also prevent the formation of rust on the exposed metal. Before I remove the paint below the connections I'd like to have the right stuff on hand. I think PJ recommended something but I couldn't find it in the archive. Perhaps someone here in Oz may know of a suitable locally available substance? Cheers
Peter TD 5801
P Hehir

Hi Peter,

Have you thought of tinning the area with solder? I reckon that would work well although it would damage the paint on the other side of the metal.

Bob Schapel
R L Schapel

I used star washers under the wire ends to dig into the paint and make ground rather than scrapping away paint. The washers are hidden from view and thus shouldn't inflict the concours judge and originality police ires. Just kidding Peter. That's how I handled it anyway.

Cheers Mate

Bill Chasser
TD-4834
W. A. Chasser

You will still have to remove any paint in the area. I used a small wire wheel on a drill motor.
Then Get some DIELECTRIC GREASE ( a little really goes a LONG way ). COAT ALL AREAS AND INSTALL. You can then spray a little paint over the connection if needed for looks.


M Grogan

Peter - the process I use is a piloted end brush that is used in the aircraft industry to insure that screws and rivets are set against a perfectly cleaned area. The piloted brushes leave a circle of completely cleaned area, which I then coat with Coporcote (or you can use the dielectric grease that M Grogan used. The area doesn't have paint on it, but it is a perfectly round area wherever a ground connection is made that (while it isn't painted) looks like it is meant to be there. See the results of the the piloted end brushes in the article Electrical Connection Preparation in the Other Tech Articles on my Homepage, linked in the signature block below.
Cheers - Dave
DW DuBois

Hi Bob. That would work on the battery box but not sure how practical it would be elsewhere. With just a few days each year when the humidity drops below 30% I'm really keen to leave the painting behind. This coming Tuesday is just the second day this year when I'll be able to paint here in Sydney with a 3 hour window predicted around 11 am.

That sounds like the stuff MG. I'll ensure the area that the paint is removed from is covered by the terminal. I don't want to over-spray the terminal. I like the idea of the grease Bill because I want to prevent any bare metal from rusting even if it's hidden by the terminal itself. I'll see if I can find some of the stuff MG recommends here. Cheers
Peter TD 5801
P Hehir

Thanks Dave. I'll check it out. Cheers
Peter TD 5801
P Hehir

Just Googled dielectric grease & came across the following which really confused me. On the Overclockers forum I found the following post from 2001;

'I was under the impression dielectric grease does not conduct electricity.'

Nobody contradicted the original post, hence my confusion. I need a medium that is a very efficient electrical conductor with metal protecting properties. Ideally something with the permanence that Bob's solder suggestion provides. I'll contact the distributor here on Monday when the stores open & get some more info. Cheers
Peter TD 5801
P Hehir

Dielectric grease will help protect the connection from corrosion, but it is itself non-conductive and would only serve to inhibit conductivity if it were to invade the connection.

I much prefer the idea of tinning the surface as it's a permanent solution. Failing that, I've found that simply using a star washer and then covering the connection with a good paint works fine.

You could use a conductive paint, or simply make your own by adding sufficient aluminium or copper powder to clear lacquer, but I think it's not really needed.

Kevin McLemore

I always use bare metal to bare metal and a coating of paint over the top.
Dave H
Dave Hill

DW DuBois -

Thanks. Excellent article on electrical connections.

Gerry Masterman closed his company "GEM Enterprises" in 2008. Do you have any other suggestions for cleaning male and female bullet connectors?

Link to Dave's article ...
http://userwebs.donobi.net/sufuelpumps/Other_Subjects/Electrical/General/Electrical_Connection_Preparation.pdf

Lonnie
TF7211
LM Cook

from: https://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm

copy and paste

Contrary to silly Internet rumors and articles, silicone dielectric grease will NOT insulate pressure connections. Silicone dielectric grease will prolong connection life as well as, and have just as good conduction performance, as a properly selected metallic powder grease (conductive grease). On the other hand, and improperly selected "conductive" grease can actually cause connection problems.

All of these dielectric greases, and virtually all from other manufacturers, both improve insulation and preserve electrical connections. They do this by sealing contaminants, moisture, and air out of connections. They also seal insulators, keeping moisture and contaminants out of insulation. They are as effective at preserving connections as "conductive" grease, and will not harm insulation.

M Grogan

Further research has unearthed the following study:

http://wings.buffalo.edu/academic/department/eng/mae/cmrl/Improving%20the%20electrical%20and%20mechanical%20behavior%20o

It seems that electrically conductive paints do exist & they actually work. These highly conductive paints use carbon black and/or silver particles to effect the conductivity. I'm making further inquiries today. Cheers
Peter TD 5801
P Hehir

Peter, the link doesn't work for me. Is it posted in its entirety or is it my set up?

Tim
TD12524
TW Burchfield

Dunno Tim. I'm not much chop with computers. I just copied & pasted the link from a site I found on Google. I was searching for 'Electrically conductive paint for use on painted surfaces' or something similar. Cheers
Peter TD 5801
P Hehir

Tim, try copying the link and replace the '%20' pairs with space characters. That's a common problem with copy/paste URLs. Bud
Bud Krueger

It really doesn't matter which of the greases, conductive like Kopor-Shield, which is conductive or any of the dielectric grease, which is not conductive. The grease used (and it can be plain old axle grease) is there to seal the connection. the wire to whatever it is being attached to should be tight enough to push whichever grease from the from between the two conductors. The primary propose of the grease is keep air and water out of the interface between the conductors and impede corrosion. The really important of the connection is that each side of it is absolutely clean dirt, paint and corrosion on each of the conductors being attached to each other. Both of the surfaces need to be clean of dirt, corrosion and/or paint - clean and shiny is the watch word. Cheers - Dave
DW DuBois

Peter

Whether this product is available here is unknown:

http://www.sanchem.com/electrical-contact-lubricant.html

The sales pitch seems to indicate a solution.

I would also evaluate the battery terminal inhibitor pressure pak sprays that are available.

Graeme
G Evans

Don't know for sure but would Weld through primer work? You can direct strike an arc through it with a MIG welder. A friendly body shop would probably give you an egg cup full.

Jan T
J Targosz

There is a pen that contains conductive paint available here in Sydney. I'll be ringing them tomorrow. Keen to use a conductive paint rather than a grease as I want to both maximise conductivity & also protect the bare metal. This conductive paint is a fairly recent development used primarily in the electronics industry & it seems as though it satisfies both of my criteria. Cheers
Peter TD 5801
P Hehir

That's not really a new product, Peter. We used to use it back in the 60's to repair broken tracks on printed circuit boards. If I recall correctly it's powdered silver packaged with an epoxy in a 2-part package. One would break the seal between the parts, mix the powder with the glue and then apply the mixture where you needed it before the glue set up. It wasn't cheap. Bud
Bud Krueger

The stuff I'm looking at Bud is a one part paint straight from the pen (about $6 in the States) or from a tub in larger quantities & was developed in 2012. I'll have more info tomorrow. Cheers
Peter TD 5801
P Hehir

Gee, Peter, the other stuff was only about 50 years ago. Ah, technology. Next they'll be putting people on the moon. Bud
Bud Krueger

The conductive paint retailer, Little Bird Electronics, confirms that his product is unsuitable at the current draw automotive use demands. The graphite base vapourises & leaves the bare metal unprotected. He knows of no conductive paint that is suitable. His only two suggestions were either lanolin which he used on his boat when the product he sells failed or perhaps copper grease. The link Graeme posted is to an American firm. Maybe someone over there could make an inquiry? Cheers
Peter TD 5801
P Hehir

Peter

The product I suggested is available on Ebay, it is only available shipped to Aus packed in a tube. If you Google the product name you will find the Ebay link.

Graeme
G Evans

What about the copper paint used to fix rear window defrosters? Permatex makes a kit these are rated at least at 12 v. https://www.amazon.com/Permatex-09117-Complete-Window-Defogger/dp/B000ALBZJY
Bruce Cunha

You can get a grease made for elect connections to prevent corrosion . It comes in a tube and be had at any elect supply house or Lowes. We called it no ox. It is must on alum cables and lugs to prevent corrosion and fires. Forrest TDC/22679
Forrest Rubenstein

This thread was discussed between 29/01/2017 and 10/02/2017

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