Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Sharing a tip: Plasti-Dip on ground points

sharing this hack-job I did recently - not sure if its new :

do you have grounds that get oxidized/exposed to abuse? why not make a homemade plastic cover for them?

I put plastidip on the ground point, let it cure, then peel it off. voila - a custom-made plastic cover for your ground point… or anything else, for that matter.

pics: ground point with plastidip cured, then peeled off, showing the bolt underneath.


UPDATE: the idea being you can put greae - or anything you want - underneath… @wesw argues that wont work :frowning: I’ll have to find out the hard way and post back… but just so we are clear, I think @wesw is right.

I like that! I usually smear a little petroleum jelly or white lithium grease on to do the same thing. But that looks a bit better and a bit more (semi) permanent.

I use grease as well, I would think the water would just collect under the plastic as it will likely not adhere tightly after a few thermal cycles or if applied over ANY grease or oil or oxidation

And if that 944 is anything like my '83 GTI, you want to make sure ALL the grounds are in good shape, I remember the engine to body ground could be a problem.

@wesw grease cannot go underneath while curing, but can add later. Makes the process slow… replied hastily as usual. We will have to see if it will hold with grease - you are sure it won’t?

but just so we are clear - I think you are right.

@texases yeah - I have read tales.

… this will stink if I can’t put grease in there and have the cap stay on.

I meant that I use grease like mustangman. I think that the plastic could loosen after a few heating cycles and water could collect under it in the vertical application you showed. I don t think it will adhere over grease either. it seems like a good method for top post battery terminals tho.

Couple of issues. First, the ring terminal still has a significant amount of corrosion on it. If left that way, it will gradually creep underneath anything you put on top of the bolt. It would be best to replace the terminal now while you’re working on it. They’re cheap and it takes minutes to do.

It’s hard to tell if they are there but best practice would be to include a star washer on either side of the ring terminal to bite into the adjacent surfaces. Face contact alone will fail much faster than if you use a biting washer (split, toothed).

The ring terminal crimp is left totally unprotected. If you’re lucky the wire is tin coated copper strands. The act of crimping often disturbs the tin enough to expose bare copper that can/will oxidize rapidly in this environment. Naturally bare copper will oxidize really fast. The crimp joint should also be protected. This can be done with a top coating or by using a heat shrink with sealant.

The plasti-dip cover most likely will not stay put by itself if you pry it off and apply grease in-between. The cover is formed to the exact shape without grease. The grease will space it off the bolt/terminal.

There are top coatings that do what you want. Fluid Film is one. Once the grounding point is completely clean and mechanically sound, you spray the FF over the connection to protect it. It won’t be as messy as dielectric grease and be less prone to collecting significant debris over time.

@TwinTurbo thanks, interesting comments. and yes indeed, I found two grounds (not shown here) that had those star-looking washers under the terminal - though not on top. I have a couple other Plasti-dipped grounds to check later, and this time, I have a larger coverage so the cap has more things and surfaces to grab onto - as I said, I’ll have to post back. and I’ll check this Fluid Film stuff.

If the oxidized copper material “creeps”, it does so because the underlying copper is oxidizing, pushing the crystals outwards - not because it is moving somewhere pe se. You can see this phenomenon if you let salt water dry out in a dish… but anyways, I agree that exposed copper will oxidize to green. I don’t know if these have tin coating - but actually, I steel-rotary brushed these until they were a beautiful copper color (and therefore unplated).

BTW since I have your attention - this could go in a new thread, with things I am thinking about - but: I figure the best way to clean the terminals that curl around and pinch onto spade terminals is with a thin file? wire-brush pipe cleaner (does that exist?) anything better - replace? I have a pic but it is really bad.

It creeps under because it lifts the surface material as it “crusts”, thereby breaking any bond you have with the good section. An analogy that comes to mind is how freezing water is able to break up mountains of rock. It gets into a crack and expands, breaking material free…lather, rinse, repeat.

One star washer is minimum, two just doubles the surface area and the cost is minimal. Glad to hear it had one!

You never want to file any electrical contact like this. That is likely a tin coated copper or brass ring terminal. Compromising the surface protection will cause it to degrade extra fast :wink: Once they begin to rust, it’s time to replace them. Or, you will be back more and more often to clean them up. In this case, it’s so easy to replace them it makes sense to do it right, do it once. It will likely last the rest of your lifetime then and after that, who cares? That being said, I have used wire brushes to clean up similar contacts and surfaces knowing full well it was only temporary…