Recommend concoctions to inhibit cast aluminum thread corrosion (Radar pedestal) ?

Only 4 years in the elements but already one of the 3 SS bolts that holds my radar pedestal (the clamshell casting that holds the array motor and transmit electronics) together was really hard to remove. What is available at most local hardware stores that would help this not to get worse one I put it all back together ? I suppose enamel paint or a few drops of motor oil in the internal cast aluminum thread holes would be better than nothing....but even better ??

I'd use Tef-Gel.

N4712 said:

I'd use Tef-Gel.

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Ditto.

N4712 said:

I'd use Tef-Gel.

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Not heard of that one...would a typical hardware store have it ? If not, a small West Marine Express ? (at probably double the price of the hardware store !)


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(on edit)
WM would have to order it. Hardware doesn't have it but does have Permatex Anti Seize lube...sounds like same thing from description....thoughts ?


Suspect Tef-Gel is better since it's considerably more expensive (not to mention it's "ultra" ! ;-))


http://www.permatex.com/products-2/...ti-seize/permatex-anti-seize-lubricant-detail


http://www.westmarine.com/buy/tef-gel--corrosion-eliminator-and-anti-sieze-lubricant--P012222212

Tef-Gel or this:

Specialty Lubricants - Anti-Seize : Permatex® Anti-Seize Lubricant

Capt.Bill11 said:

Tef-Gel or this:

Specialty Lubricants - Anti-Seize : Permatex® Anti-Seize Lubricant

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I have used permatex anti-seize to prevent galling between steel bolts and aluminum threads in marine and automotive applications. I use the nickel based formula. It works great (in fact the last boat I had, I used it to coat clamshell type clamps I made to mount the radar to the rigid FB aluminum cover frame) The only downside is it is messy...use very little and wear disposable gloves that are discarded immediately so you don't touch anything else and spread it everywhere! If you use too much it, rain/spray runoff can cause a little grey streaking to adjacent glass but it cleans up easily and that event stops after a little time in the weather. The Tef-gel does not have that issue but is harder to locate and more costly.

What you want to do is electrically insulate the stainless from the aluminum to limit galvanic corrosion. Believe it or not, Tef-Gel produces a very thin film between the two that limits corrosion. Other sealants might work, but boat riggers all use Tef-Gel for that purpose.


David

Haven't tried it for your application but I see no reason this stuff shouldn't work.
Super Lube 3 oz. Tube Synthetic Grease with Syncolon PTFE-21030 - The Home Depot

Can't use copper and aluminum. If you need a thread compound use the aluminum-based one. Copper is good for other stuff, not stainless and aluminum.

Xsbank said:

Can't use copper and aluminum. If you need a thread compound use the aluminum-based one. Copper is good for other stuff, not stainless and aluminum.

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++ pay attention to this or you will pay heavily down the road.

RT Firefly said:

Haven't tried it for your application but I see no reason this stuff shouldn't work.
Super Lube 3 oz. Tube Synthetic Grease with Syncolon PTFE-21030 - The Home Depot

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I have that stuff, like it and use it for all sorts of things, but it is not as durable as TefGel, which purpose-designed for exactly what the OP needs. You can get TefGel in SC in a couple of days from Florida or a place like Defender.

Funny, I just used some Super Lube this afternoon to grease the pole to a free standing bird feeder to keep the squirrels off.

An outboard mechanic once taught me to coat the threads of stainless bolts with Permatex #3 gasket compound when you were putting them into aluminum. It really worked. The next time he worked on an engine it was a lot easier to take apart.

It's counter intuitive but I think Locktite will also prevent stainless from binding with aluminum.

HopCar said:

It's counter intuitive but I think Locktite will also prevent stainless from binding with aluminum.

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Blue Loctite maybe.....Red Loctite would lock the threads.

Never-Seize. The standard seems to work fine between aluminum and stainless, but the Nickel is best for mixed metals in a salt environment. Been using it on boats for over 40 years and screws always come back out even years later.



Ken

I'd suggest Tef-Gel as well. I buy it at an electronic components supply place; much cheaper than from a marine supplier.

I have had good lick with tefflon tape .

It squishes and doesn't leave room for standing air & water.

Tef-Gel definitely. Order online and keep in tool box. Used sparingly (according to the instructions) a tube lasts a long time. Get this stuff.

Another vote for Tef-Gel. We used it all over the sailboat, including when we changed out all the standing rigging (ourselves). Expensive but really does last a very long time. We've been using the same tube for around eight years and it isn't even half gone.

I use boat trailer wheel bearing grease anytime SS is threaded into Al around salt. Learned the trick from outboard mechanics. Pull a gearcase ten years after using the stuff, bolts come right out and are still greasy.

Anytime I buy an outboard, I take as many bolts out that are easy to get to and grease em up.

The grease is cheap and readily available. Probably does the same thing as the tef gel, keep the water out of the galvanic couple and all is good. I'll look into that tef gel.

I bet all of the suggestions in this thread will work fine. Be sure to get some under the screw heads as well as the threads.