Topic: SS + Aluminum + copper based anti-sieze revisited

[SohRon]

I've been using Copper based anti-sieze for my stainless steel case bolts because it has been recommended on this forum (more than once, actually). I recently was made aware of the following discussion (copied from another website) that makes me wonder if this isn't such a good thing to do. Here's the quote; tell me what you think:


"In a galvanic corrosion situation involving aluminum and steel, we're not worried about the steel. The aluminum is the sacrificial metal and will corrode preferentially, protecting the steel. The presence of water is absolutely necessary
for the reaction to occur.

Plated steel bolts (plated with either cadmium or zinc) will afford some protection to the aluminum, but only as long as the plating lasts. It's being used up as it sacrifices itself to protect the aluminum. As soon as the plating is used up, the sacrifice of the aluminum parts to the steel will begin.

The white powdery coating on one of the bolts looks a lot like aluminum oxide. Guess what part is really getting eaten up. That's right, the aluminum case.

Now if you want to really see aluminum go to pieces, get copper involved. Copper eats up aluminum in a situation of dissimilar metals with water involved. Copper based anti-seize should NEVER be used in contact with, or where it can get in contact with aluminum. Use the aluminum powder anti-seize, always.

My knee-jerk reaction recommendation to fix this corrosion problem would be to:

Clean up the existing corrosion. If the steel bolt hasn't been significantly corroded (just light surface corrosion) clean it up and reuse it. If there is any question as to a reduction of the cross area of the bolt due to corrosion, replace it with the proper factory bolt.

Spray the bolt with WD-40 or other anti-corrosive that is compatible with the rubber pieces. (I went out to the garage to look at the mounts and noticed there is a rubber piece in the joint. Like I said, I just got the bike. Vibration isolation part, or seal to exclude water, or both?)

If you've got copper anti-seize where it can get in contact with the aluminum cases, clean it out of there completely.

Use a little RTV to seal the assembly. The basic idea is to get rid of the water incursions into the bolted joint. Without the water, no corrosion.

Blue Loctite on the threads, not copper anything.


304 stainless fasteners are fine with in contact with aluminum. There is a surface passivation involving the chrome oxides that form on the stainless that precludes the formation of a galvanic cell under most conditions.

Wally advises that by just looking at a couple of photos of one component of the problem he really can't offer a professional opinion from such limited information. There may be other factors involved, but the basic premises of keeping the water out and not using copper are sound."

[lone*X]

Very interesting question here.  So I go a googling and find this site.  The chart on this page recommends zinc based anti-sieze for aluminum to steel.   Interesting read.

http://www.sacskyranch.com/antiseize.htm

[Greggo]

Hmmmm, interesting. 

[Rgconner]

Very interesting question here.  So I go a googling and find this site.  The chart on this page recommends zinc based anti-sieze for aluminum to steel.   Interesting read.

http://www.sacskyranch.com/antiseize.htm

hah! That place is just a few miles from my house, and less than a mile from where I bought my CB550.

Gonna have to check that out, that looks like good stuff.

[KingCustomCycles.com]

Here is the composition chart for the ONLY anti-seize to use where aluminum, steel, and cad plating are involved, It is the industry standard in aviation.  Also says it prevents corrosion in even severe enviroments:

Product Name: Permatex - 133K ANTI-SEIZE LUBRICANT 8OZ
Item No: 80078
Product Type: Lubricant
2. COMPOSITION/INFORMATION ON INGREDIENTS
Component Weight% ACGIH; TLV-TWA OSHA PEL
DISTILLATES (PETROLEUM),
HYDROTREATED HEAVY
NAPHTHENIC
64742-52-5
20-40 Not listed Not listed
DISTILLATES (PETROLEUM),
HYDROTREATED LIGHT
NAPHTHENIC
64742-53-6
20-40 5 mg/m3 TWA ACGIH Not listed
CALCIUM OXIDE
1305-78-8
15-25 2 mg/m3 5 mg/m3
ALUMINIUM POWDER
7429-90-5
<10 1 mg/m3 15 mg/m3
GRAPHITE
7782-42-5
<10 2 mg/m3 15 mppcf
MINERAL OIL
64741-44-2
<5 5 mg/m3 Not listed

[MidnightLamp]

Permatex 133H is commonly available at your local Canadian Tire (or whatever your american equivilent is). Very simmilar to the above, have used it on everything I own (high performance automotive engines and bikes). Works VERY well.

Cheers

[bollingball]

Hey King you want to translate that

[KingCustomCycles.com]

Sure: it has aluminum and graphite in a mineral spirits carrier.

[millerza]

Anyone had any issues doing this?

[Lostboy Steve]

What king means is it's base is made of mineral spirits. The rest is all metal.


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[lrutt]

My understanding is that copper AS should only be used on exhaust studs or possibly sparkplugs. Honestly I don't use it on either, just my regular old can of military grade stuff I've been using for 25 years. It's dark and thick as paste but never has let me down.

[KingCustomCycles.com]

1100 series aluminium is copper free, I have no idea what type of aluminum is ground up in there.  We were taught to use it in Airframe and Powerplant school, and every airline, turbine engine company, or aircraft shop I ever worked at used it.  I only came across the copper at NAPA and have seen it in car mechanics tool boxes.  Aluminum is now common in cars but back in the day, copper was OK. I only reference the aircraft use because they are primary constructed of aluminium and the standards to repair and maintain them are stringent to say the least.  To belabor the point a bit further, if a specific antiseize is required, it will specify that in the approved technical data for the specific repair or assembly. 

[SohRon]

Thanks for all of the responses; it looks like the copper AS is a major no-no. The zinc based stuff sounds good as zinc is right at the top of the Galvanic Series, being one of the more anodic metals; of course, that's what Honda used on all of the nuts, bolts and washers we use on our bikes.

It's interesting that the Loctite copper AS is specifically recommended for use on aluminum heads:  "Applications: Spark plug threads (especially in aluminum heads, which can strip easily)..."  So we have one "expert" telling us we should never even allow copper AS into the same room with our aluminum heads, while another "expert" recommends it specifically for our aluminum heads. And people wonder why I get confused...

On a Galvanic series chart, copper falls right in the middle between SS and aluminum, meaning that the aluminum will corrode faster than either of the other two, and there are those I've spoken to about this that say the copper added to the SS and aluminum mix may even hasten the demise of the aluminum in a galvanic corrosion condition.

I'm thinking it's not worth the risk; I'm certainly leaning towards the zinc based AS...

[cwchan]

Aircraft are subject to much more weather & humidity over their lifetimes than our motorcycles.  Remember water must be present for a reaction to occur & it has to get in the threaded hole.  Do stock steel bolts have anti-seize when they come from the factory?

[SohRon]

Do stock steel bolts have anti-seize when they come from the factory?

Stock bolts are zinc coated, which acts as an anti-corrosion element by being a sacrificial matrial. And the steel itself isn't that reactive with aluminum.

We're talking stainless steel and aluminum, which is a whole 'nother story. Lots of folks (including myself) are replacing their stock bolts with stainless, and that's where the potential problems arise.

All sorts of things may provide the electrolyte necessary for galvanic corrosion, from rain to high humidity to just plain air pollution; if you live near the ocean you're particularly vulnurable. Aluminum will sacrifice itself to stainless in a heartbeat, and that's what we're trying to  avoid.

And, of course, galling (one material smearing onto another) is a particular problem when mixing hardened stainless with soft aluminum; the anti-seize addresses that as well.

[trueblue]

I have always used nickle anti-sieze on all bolts used in aluminium, unless of course for whatever reason I have used loctite.  If I don't have any nickle anti-sieze, 2nd option is molibdium di-sulfide grease, works just as well and doesn't provide any corrosion issues.

[dave500]

ive always used "kopper kote"and never had trouble,,i might try that white zinc sunscreen you put on your nose from now on,and put the "kopper kote"(TM)on my nose and see what chemical reaction i get from my wife?

[dave500]

ok my wife just told me to sleep on the couch,i dont get what she had against me using that white zinc sunscreen on my honda bolts?

[SohRon]

I've been using copper on cars/motorcycles since the 1970s and had no problems... Don't believe theories based upon roofing products...   I would think the chemical engineers at Loctite have a bit more education than your average back yard gear-head extrapolating some unproven theory.

Good on ya', mate! Was waiting to hear from the hyperbolic crowd. The above info is hardly based on "roofing products", or your "average back yard gear-head", but a discussion held with aluminum industry specialists, and since I've brought this up among my engineering friends, they're in complete agreement.

I give you permission to use whatever AS on your bike you want, and the rest of us will stand behind your right to do so.

ok my wife just told me to sleep on the couch

Women just don't understand...

[dave500]

oh she unstood alright,,she just didnt want a kopper koted kunt!,,,i knew someone would walk right into that one!

[dave500]

im snipped already to save on copper.

[Kong]

First off let me tell you I have a lot of experience with corrosion as a result of using stainless fasteners and aluminum devices together with corrosion being the result.  I have also been using coper enhanced high temperature anti-sieze compound.  Where I use compound I don't get corrosion, where I don't use it I do get corrosion.  Oh, I'm talking about a saltwater environment (I have an off-shore fishing boat that I keep down at a place we have on the coast) where corrosion is an every-resent problem.

[crazypj]

As KONG said, I'm pretty sure that a copper based lube is far superior to no lube at all.
Ordinary grease doesn't work.
 The stainless screws are going into a not particularly good quality alloy, usually with quite a lot of zinc and various other stuff swept off the cutting room floor in the mix
Zinc screws into zinc alloy corrode real quick and lock together.
 I'll continue using WURTH copper grease until the tube runs out then I'll look for alternatives

[SohRon]

Thanks for the replies, guys; this is the kind of stuff I was looking for.

I've heard of others who have been using the copper compound for years with no problems, so I guess there is room for doubt; anecdotal evidence surely has its place.  However, after extensive research and conversations with my engineering contacts (all of whom gave me really strange looks when I mentioned the combination in question), I'm just not going to risk it; why should I when there are plenty of alternatives available?

Thanks, again, for joining in the discussion.

[millerza]

ok so im not going to pull out the ones with copper and clean them, but I see no reason I cant start using the silver stuff