Loctite v. anti-seize

[Leghorn]

(Hopefully, this has not been covered before.)

I've always kept a bottle of blue Loctite on hand to secure critical fasteners, but lately there seems to be more talk about using anti-seize, instead. It's my understanding that anti-seize is needed to prevent bi-metallic corrosion. Does Loctite have anti-corrosive properties as well? For that matter, does anti-seize provide any of the security that Loctite does?

What should you do, for example, where a titanium bolt secrues a cast (iron?) piece such as a brake caliper and bolts into an aluminum fork? I don't want corrosion there, but I'm more concerned with security. Short of safety wiring things, is there a rule-of-thumb that would apply?

Also, there are some newer "environmentally friendly" anti-seize compounds on the market. Do they work as well as the messy stuff?

 

[radman]

Anti-seize on bolts that tend to corrode or are in areas of extreme heat. Loc-tite on bolts that tend to loosen through vibration or those that fasten mission critical parts. Loc-tite does tend to prevent galvanic seizing, but isn't commonly used for this purpose. IMHO, I think fears of galvanic corrosion/seizing of the aluminum/steel interfaces on the FJR are over played, I haven't seen much evidence of it on bikes that are kept clean, free of salt, and with wire rather than chassis grounds.

 

[panthercity]

...with wire rather than chassis grounds.

[SIZE=14pt]WARNING![/SIZE] Ignorance Alert!

Haven't run across this yet. When you've a moment, would you enlighten me, por favor?

 

[Geezer]

I use anti sieze on anything that I expect to be taking on and off and loc-tite on most other things. I find that anti sieze not only serves to insulate different metals from each other but also helps smooth the threads which are sometime pretty rough or galled when cut into soft metals.

I have had spark plug holes strip on aluminum heads on two ocasions in my life so I now always use anti sieze on spark plugs even in iron heads. I also use it on wheel lugs of my cars because it makes them easier to get off in the future even though they are steel on steel.

I believe that loc-tite also serves to insulate between the two metals ( nut and a bolt) so I am comfortable using loc-tite on steel bolts into aluminum threads for things that I don't expect to be taking back off. Others will probably disagree on this one but it works for me.

 

[radman]

Rather than using a running chassis ground for all the wiring, such as rear lamps etc, there are ground wires in the harness that run to a central ground location. Although the chassis is still grounded, it doesn't depend on the metal to metal contact integrity throughout for good grounds. This method of grounding also helps prevent components from becoming permenantly attached due to galvanic action (something that usually occurs from the contact of dissimilar metals). At least, thats been my experience.

Edit-the spark plug stripping I have seen comes from 2 things-overtightened plugs (especially tapered seat types) or plugs that have quite a bit of carbon build up on the lower exposed threads. Another reason to change plugs more often than current manufacturers recommend. Anti-seize will not always save ya if this is the case.

 

[Leghorn]

Radman, can you entertain a follow-up question? I don't understand all of your answer to panthercity. By "running chassis ground," do you mean that each electrical device is grounded to the nearest or most convenient point on the chassis?

In a recent thread on power connector busses, some riders displayed and/or discussed installing a centralized ground bus, which in turn was connected to the negative terminal on the battery. Some of my farkels, such as the Powerlets, are individually grounded to a convenient point on the chassis. My Power Commander is grounded directly to the battery. This is all per the instructions on the individual farkles. So do I have both wire and chassis grounds? I'm confused.

 

[ionbeam]

Note that when using loctite and especially anti-seize, they work as thread lubricants during install which alters torque values. I believe that torque requirements will be ~ 10% less on gooed hardware. The moto-smart and always loquacious Radman would know for sure.

By "running chassis ground," do you mean that each electrical device is grounded to the nearest or most convenient point on the chassis?

Yes.

my farkels...Powerlets, are individually grounded to a convenient point on the chassis...Power Commander is grounded directly to the battery...So do I have both wire and chassis grounds

Yes! It is always best to use a grounding block and return that to the battery. Surprisingly, the chassis doesn't make a good ground point. Good grounds are critical for communications and entertainment systems and these items should go directly to the battery. Heavy current draw items that power constant loads such as lighting can be run off the main chassis as long as the battery cable is grounded to the main chassis also. When you start getting into sub-frames the quality of chassis grounding goes down.

Alan

 

[radman]

Pretty much any product applied to a bolt acts as a lubricant, and values need to be adjusted for this. Dry torque values mean just that-clean dry threads. And yes, chassis make for crappy grounding. You'll notice most motorcycles use wire grounds rather than local, due to the very thing we are discussing here-many dissimilar metals connected, with corrosion ( and therefore high resistance) points abounding. As a result, the wire grounds terminate at a point near the battery, to try to eliminate (note most electrical scoot problems deal with grounds rather than power) poor current flow. Again, this is based on what I have found over the years, not on any engineering expertise on my part.

 

[Grumpy]

Galvanic corrosion requires contact between two metals that are relatively far apart on the periodic table, like steel and aluminum, PLUS moisture to "complete the circuit".

 

[Leghorn]

Thanks to all.

I was already undertorquing some of the smaller fasteners and the oil drain plug by about 10% anyway. Maybe I should extend that policy to everything that is "lubed up."

In addition, I think that I'll set up a ground block from the battery and reroute those existing chassis grounds.

Also, Radman, thanks for clearing up the matter on Avon "B" spec tires over on the other discussion thread.

 

[panthercity]

Rather than using a running chassis ground for all the wiring, such as rear lamps etc, there are ground wires in the harness that run to a central ground location. Although the chassis is still grounded, it doesn't depend on the metal to metal contact integrity throughout for good grounds. This method of grounding also helps prevent components from becoming permenantly attached due to galvanic action (something that usually occurs from the contact of dissimilar metals). At least, thats been my experience.
Edit-the spark plug stripping I have seen comes from 2 things-overtightened plugs (especially tapered seat types) or plugs that have quite a bit of carbon build up on the lower exposed threads. Another reason to change plugs more often than current manufacturers recommend. Anti-seize will not always save ya if this is the case.

Thanks. That makes sense. I've never been a fan of attaching the ground wire to the nearest "bare" metal, just didn't recognize/understand the phrase.

Ain't learnin' gud!

 

[jestal]

Somethings to keep in mind when using anti-seize...

Most antiseize compounds are electrically conductive. If you use antiseize on the spark plug threads makes positively sure that none of the antiseize gets on the spark plug insulator/porcelean itself. This is not so hard to do the first time antiseize is used but gets progeressively diffcult later when new plugs are fumbled into threaded holes that are slathered with antiseize from previous installations. Personally, I vote for no antiseize on spark plug threads due to the contamination issue.

Antiseize is definetly a good high pressure lubricant. Since most of the bolt "torque" applied goes into overcoming friction in the threads the addition of the antiseize dramatically affects the torque/tension relationship in the threaded fastener. It is very very easy to strip or break a fastener that is torqued in a joint with antiseize applied. You absolutely MUST back off on the torque significantly when antiseize is used.

If there is any critical fastener that you want to stay tightduring use do not use antiseize. Many fasteners in critical locations can loosen with normal operation so adding antiseize has the opposite affect of a loctite thread locking compound making the joint much more likely to loosen than normal.

 

[Leghorn]

Thanks, Jestal.

If I'm reading between the lines correctly, I'd have agree that there are certain critical bolts that are better kept "dry," using neither anti-seize nor Loctite. The bolts that come to mind are those for the calipers and axles (main & pinch). Short of having to drill or buy bolts for safety wiring, I've been marking the bolt and an adjacent surface with a white metal marker. The white marks are waterproof and easy to visually check for movement; moreover the marks wipe off easily with alcohol or a stronger solvent when it's time to retorque the bolts.

 

[jestal]

"Loctite" is used generically for most any thread locker but keep in mind that there are a large number of different Loctite compounds. Anything from a "permanent" joint to a sealer to a mild thread locker is available. Putting the correct grade of loctite in the joint is perfectly fine most all joints. It really cannot hurt. You do not want to use permanent grade loctite for the axle bolt, for example, but a relatively weak thread locker would be fine to prevent loosening.

Check the Loctite website out for a crib on what loctites do what and make sure the bottle you pick up is the correct stuff for the job at hand. About the only thing generic about Loctite is that their products (for the most part) are aneorobic compounds meaning that they set up in the absence of oxygen....so the loctite will not set up until it is sealed into the threads of a bolt in the joint.

Most any of the thread locker Loctite products will be weakened/destroyed by excess heat. Good thing to keep in mind if you have to dissassemble a joint that loctite was used on. Or, if you are afraid to use the loctite, don't hesitate if the joint can be heated if dissassembly is needed later. You can heat with a propane torch or some such device. You don't have to melt the joint or get it cherry red...LOL...just some gentle local heat is enough to soften the loctite and the joint will come right apart.

You don't have to completely slather the threads with loctite, either. Usually just a tiny tiny bit on the end threads will ensure against movement later on unless the joint is really being stressed, then a bit more application might be required.

Loctite does act as a good high pressure lubricant so keep that in mind if you use loctite in the joint....torque values will have to be lowered slightly to keep bolt stretch in line.

Many production fasteners in engines/cars are coated in the thread area with a micro-encapsulated Loctite product. The colored "patch" on the bolt threads looks like paint on the threads but it is the micro-encapsulated loctite product. The pressure of the threads in the joint ruptures the encapsulation and the loctite can then setup. The joints and fastening technique are designed for the lubricating qualities of the loctite patch and the subsequent sealing and/or thread locking action.

 

[jestal]

Regarding the chassis grounds and discussion over whether to use chassis grounds or hard wired grounds.....

Whenever the electrical load on a conductor changes the overall voltage drop changes. When all circuits were 12 volts and loads measured in amps this was not an issue. You could have 20 different devices "grounding" thru the engine block to chassis to battery. The problem with electronics of any sort on a bike or car is the fact that everytime the loads on that common ground path change the voltage drop changes. When the system is operating on loads of milli-amps this matters. For instance...if the coolant sensor was grounding thru the engine block-frame-battery cable then it would send a reading to the PCM relative to the current passing thru the sensor. If, suddenly, 20 amps worth of lights were turned on and that current would go to battery thru the same engine-chassis-cable ground path there would instantly be a shift in the coolant temp reading since the (total) voltage drop thru the ground path would be different. This can be significant as different devices turn on and off and sensitive sensors like the MAP and coolant and such would be affected. I have seen cases where oxygen sensor voltage read at the PCM would jump .3 to .4 volts as the ground plane changed from turning the heater blower on.....all due to inappropriate common grounds. That is why most all devices in the system have their own separate wire to ground at the battery so that the current on that particular ground is only affected by the load on that circuit. This is often refered to as a voltage shift in the ground. Ground is supposed to be "ground" but if you take a system operating under full electrical load and take an accurate meter and start checking the voltage difference between different "grounds" you might be surprised to find that ground is not always ground.... Running a separate wire to a known common ground is the only way to make sure that this doesn't trip you up.

Even in cases (such as the PCM sensors) where the ground at the pcm might not be at the absolute ground of the battery the PCM will only look at the difference beteen the PCM voltage and the PCM ground and that will be fine as long as nothing else is introduced to shift it under load. So, all the sensor and injector grounds go straight to the PCM, not to a chassis or battery "ground".

The use of chassis grounds for lights and such really showed up on aluminum snowmobile trailers when they first hit the market in the late 80's. Everyone made the aluminum trailers and grounded all the lights thru the trailer chassis just like on steel trailers. Since snowmobile trailers are almost always used in the presence of road salt and moisture the trailers basically fell apart at any bi-metal joints and the lights would quite working many times due to loss of ground as the wires rotted off. Virtually all trailers like this went to sealed harnesses and direct wired grounds that do not rely on the chassis at all.

Volkswagen had a severe problem years ago with a transmission ball bearing failing deep in the trans. Quite a mystery as the bearing was properly designed and not overloaded or anything. The reason it failed occasionally was that mechanics would sometimes leave off a large ground strap from the engine to the chassis when servicing part of the suspension. When this happened all the electrical load on the ground path from the engine/powertrain to ground ended up going thru that bearing. The entire powertrain is usually isolated electrically by the rubber mounts so the ground straps are mandatory to carry the electrical load. In the VW case, the load went thru that bearing, micro-welded the balls to the race in spots and then broke the welds as the bearing turned. This disturbed the bearing surface and caused it to fail. Replace the ground straps when you remove one for service on anything. They are there for a reason.

 

[Geezer]

Wow, I have certainly learned a few things from this thread. It will be difficult for me to break the anti-sieze on spark plug habit but I will make sure that I use it very sparingly on them if I can't resist.

I am a big fan of loc-tite and I'm glad to hear that those of you who are more knowledgeable also use the stuff.

 

[yanktar]

"When do I use Loctite and when do I use anti-seize?"

I've never understood this question.

It's like "When do I use mustard and when do I use whipped cream?"

Um, well, you use them for really, REALLY different things.

Who has the sig "If it moves and it shouldn't use duct tape. If it doesn't move and it should, use WD-40"? Yup, same for Loctite and anti-seize.

 

[Rogue]

Who has the sig "If it moves and it shouldn't use duct tape. If it doesn't move and it should, use WD-40"? Yup, same for Loctite and anti-seize.

:notme:

 

[yanktar]

Who has the sig "If it moves and it shouldn't use duct tape. If it doesn't move and it should, use WD-40"?  Yup, same for Loctite and anti-seize.

:notme:

Ah, well. The second sign of aging is forgetfulness...

What's the first, again? I forgot!