Is aluminum anti-seize compatible with copper.

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I'm getting ready to install new spark plugs in my Harley, it uses old-school style plugs where it is recommended you use anti-seize on them. When I installed the plugs currently in use i used copper anti-seize, however I was going to use aluminum anti-seize this go round. Since I assume the threads will have some remaining copper anti-seize left on them when I pull the plugs, do I need to somehow clean that off before installing the new plugs? If so how would I clean the old grease off? About the only thing I can think of is some parts cleaner on a Q-tip or something like that .
 
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Really prefer copper based to aluminum based as far as avoiding contamination/grounding issues around the plug center electrode. Once you installed the last plug, there is just about enough copper left on the threads to serve for the next service period.
 

MoreCowbellAz

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The aluminum anti-seize that I was going to use was made by Permatex. There's no technical reason for going with the aluminum other than I am out of the copper and the aluminum I already have on hand as I use that on most other things, axles, adjusters, etc. And in fact the only real reason I use the aluminum there is because it's easier to spot dirt or rust or corrosion, copper colored anti-seize makes it harder to distinguish. So mainly just trying to simplify, but not if it means creating problems somewhere. The owners manual doesn't specify which type. Maybe vw's advice is simpler still, just rely on the old anti-seize that's already leftover on the threads. These plugs get swapped out pretty often, 20 K, so it's not like the stuff has been baked for all that long.
 
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I doubt mixing metal impregnated anti seize greases on threads has much, if any negative effect. Because if it did you would be hearing more about it. With the millions of vehicles out there, most of which are serviced by different garages / dealers / mechanics, all of whom use whatever anti seize they have on hand. Be it Zinc, Aluminum, Copper, or Nickel. If there was some type or form of negative electrolysis / erosion / conductivity taking place, it would be a bigger issue. It's not an issue at all. But you read about seized / stripped / frozen / broken nuts, bolts, studs, and spark plugs everywhere. Personally, I believe having different types of anti seize applied, is better than having none at all. No, I don't have any, "scientific data" to support this. But again, if it caused negative issues in any great abundance, you would be seeing and hearing the negative results, posted in automotive forums like this one. You don't. And having a bunch of people saying don't do it, isn't saying much if they don't have the negative results to support why. Bottom line. If you've used copper in the past, and you want to use it again, go ahead. Nothing bad is going to happen.
 

JHZR2

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I was under the impression in that application, that copper was desirable because it has much better conductivity than aluminum or nickel or moly or Zinc (some other common variants). Since in that location, theres enough heat to avoid electrolyte wicking, it's much less of an issue/concern to have dissimilar metal corrosion. Other locations you might think twice about copper and aluminum being together. As an aside, I never had issues running Cu anti seize on my wheels, but it would all seeem to disappear. Wheels were no worse for it, and never seized on... I just changed to zinc anti seize because it's a better option, IMO between steel and aluminum. But extreme conductivity for plugs isn't required... It would be nice to have an application chart of good/better/best/don't use for different metal combos..
 
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If Harley is recommending anti-seize, do they not say what kind ? What does the spark plug manufacturer say to use ? Anti-seize comes in several different materials, each with a specific purpose. See what Loctite says to use. https://www.all-spec.com/loctite-anti-seize Auto parts stores may have a 'small' packet at the cash registers if you don't want to buy a large container.
 
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Originally Posted by MasterSolenoid
If Harley is recommending anti-seize, do they not say what kind ?
It's a 50/50 chance that what Harley recommends will help him. He's already used copper anti-seize on them and no doubt some of that material remains in the internal threads that he'll never get removed. If HD says to use aluminum, then he's back to his original quandary of asking how copper and aluminum anti-seize will chemically react with each other, if at all.
 
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My neighbor, a salesman for Dow-Corning, told me to use an anti-seize the metallic base of which is dissimilar to either of the metals that you don't want to seize. He gave me a tube of his company's stuff. I still have some of it and that was 40 years ago.
 
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All I have ever used has been copper or nickel based. Aviation spark plugs use a VERY DARK gray Molybdenum based anti-seize.
 

MoreCowbellAz

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Correct, Harley says use anti-seize but doesn't specify which type, which indicates to me any kind. But I'm sure that's aimed at HD branded plugs which may not have any anti-corrosion plating, IDK. The plugs I've been using and continue to use are Champion 810, and their website doesn't mention anti-seize at all one way or the other, at least not that I can find. Perhaps those plugs don't even need anti-seize, I guess I'll drop them an email and see what they say. I always assumed copper core plugs needed anti-seize while Iridium didn't, but maybe that's a bad assumption. The Permatex site shows aluminum can be used on marine spark plugs (why specifically marine I don't know), and copper for all plugs in aluminum heads. My guess is this is all over-thinking it and no calamity would happen either way, but I'm curious nonetheless. Interesting in a nerd sort of way I suppose.
 
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Originally Posted by MoreCowbellAz
I always assumed copper core plugs needed anti-seize while Iridium didn't, but maybe that's a bad assumption.
The copper (or none) located in the center electrode has absolutely nothing to do with the price of tea in China.
 
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Copper in contact with aluminum with moisture added results in galvanic corrosion of the aluminum component. Is that a problem? I don't know. There may be other potential galvanic reactions of either anti-seize with the fastener or spark plug and theads. I never use anti-seize on spark plugs.
 

MoreCowbellAz

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Originally Posted by Linctex
Originally Posted by MoreCowbellAz
I always assumed copper core plugs needed anti-seize while Iridium didn't, but maybe that's a bad assumption.
The copper (or none) located in the center electrode has absolutely nothing to do with the price of tea in China.
I guess what I meant was it appeared to me that there was a general tendency that the makers of iridium plugs also put on anti-corrosive plating while a lot of those less expensive copper core plugs didn't have that plating, presumably to bring the cost down. I thought perhaps the reason behind that was because one is a more modern design and one was more old-school, not because there was something inherant that says iridium needed to be matched with plated threads. Two separate things I understand, i've just never seen an anti-seize come on a plug from the manufacture except on a copper core. All of the iridium plugs I've seen have that plating and they say specifically to not use anti-seize. But I am no plug expert, just my casual observation.
 

MoreCowbellAz

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Well there you have it, according to Champion they don't recommend using anti-seize Of any type, due to overuse in which case it messes up heat transfer as well as possibly contaminating the electrode. They go on to say if I do use some, use only a very small amount and start at least two threads up from the bottom. Even in that case, they don't mention which type of anti-seize to use. So I guess to them any type or non at all. As an aside On the champion website they have an article about removing difficult or stuck plugs, and even there they never mention using some type of anti-seize to avoid this in the future. They talk about using penetrants etc instead to loosen things up before removing.
 
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Here is a photo of Permatex 133H Anti-seize. I have a lot of it left. I don't think it's available any more but if you google it you'll find it was a blend of aluminum, copper and graphite. In fact maybe that's one you used? It looks like aluminum but actually has some copper in it, so I don't think they are a problem to mix. Just my 2cents .

68CE2136-A316-47B7-A608-3791C93945EE.jpeg
 
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Yes, that's the perp right ^ there. 133H with the graphite. Must be the ingredient that makes it want to carbon track, Like others mentioned, avoid the first few threads, tiny portion per plug (less than a sharpened lead of a No.2 pencil,) & I would try to apply every OTHER time but that would require a log book. lol. Don't get cute & use engine oil either, that can turn to molasses or cement-like carbon too. Becomes scary-tight.
 
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