What can be used on stainless bolts to prevent galling to aluminum via electrolysis?

Not strictly a Mav/Com question, but a general technical question, and likely applicable for several combinations of bi-metallic contact situations.

On my boats, I have had several (MANY!) situations where stainless bolts are inserted into aluminum heads and blocks, and when you come back in a year to remove the bolts, electrolysis (galvanic corrosion) occurs, essentially "welding" the two together. I have often been forced to replace the aluminum components due to the bolt being permanently fused, and unable to be removed even after destroying the aluminum part.

Anyway, what would be a good brush-on or dip-in product to use on the bolts prior to assembly to prevent this from happening?

Many boaters shy away from anti-seizing compound, because it often contains other metals which may worsen the situation.

 

My best suggestion would be to always use a good washer. That is pretty much their purpose.

 

Scott, ehen i took off my transom I used some grease that I got from West Marine. Not sure if it worked, because as you know I got rid of the boat.

 

I have always used Anti-Seize made by Permatex. If it is an aluminum part it gets a liberal coating on the complete bolt, threads and shoulder. I have used it on just about everything from building motors to assembling pumps to robotics and automation equipment (that is not used in food and consumption purposes) and have never had any problems removing the hardware at a later date. Water pump bolts passing through the aluminum timing cover come right put once they are broke loose. That's my opinion anyways. Good luck.
The other method, if you have the ability, (equipment) to do so you could contact Iguss and purchase their thermo self lubing bushings and then drill out the passages and insert them then put the bolts through the bushings. They make a great product.

 

I have used permatex anti-seize, on ALL of my projects, but some boat guys are saying it is going to make the problem worse, faster. Personally, never had a problem with the stuff. Even use it on all my lug-nuts.

And yes, from the tip of the bolt all the way to the head. Anywhere there is exposed aluminum, it starts to corrode and weld itself to the stainless.

 

Antisieze or moly compound

 

i build packaging equipment for a living and all we use in my area is stainless bolts. we don't have a lot of aluminuim in our machines but with the stainless bolts we always coat it with loctite anti seize #37230 as a second choose and loctite #248 thread locker as a first. we use mostly the threadlocker as it stops the galling by the bolts and also with the abuse the machines take they don't fall apart so easy. yes lockwashers are suppose to hold the bolts but i have had alot of them back out when some people don't put as much zest into tightening things or the cheep washer they buy spread when you do tighten them down good

 

In my 25 years of fixing roof top a/c's, Anti-seize has never made anything worse, and they sit out in the weather 24/7/365....

 

A number of years ago I bought a restored drag boat. The guy that did the restoration told me that he never used anti-size, but did use thread sealer in every bolt that went into aluminum....................and I've done this ever since. I use the Loctite sealant in the white tube.
Had the boat for awhile and never had a problem removing any ss bolts.

 

Here is a picture of the boat.

 

Thanks for all the info! What the guys with the boats say to use is Permatex 3D Aviation Form-A-Gasket, which is essentially a thread sealant.

Haven't found the stuff on the shelves yet, so if I don't I will use the Permatex anti-seize, which I already have.

It looks like the point is to just put a thin layer of "something" waterproof between the two materials.

And to debunk the "anti-seize has metal in it and conduct electricity" theory, I tested it with a volt-ohm meter last night, and no, it does not. I could even dip my probes into the anti-seize and actually touch the two probes together, and still no current, until I rubbed them back and forth against each other enough to clean the contact area between the probes.

So, anti-seize may still be a problem if the threads rub together enough to clear it away. But I doubt it.

 

I worked offshore in the Gulf 35 years ago and we used the same stuff (looked just like the Permatex A/S) on all the bolts, I distinctly remember using it on stainless bolts screwed into aluminum breaker boxes. I use Permatex A/S now on all bolts that I think need A/S compound. Never had one yet that welded itself in the hole.

 

Have you tried adding additional Zinc's to combat the break down? that's where I would start.

 

OK, I'm a dumba$$, what's the doo-hickey in front of the RH valve cover that looks like a lathe handwheel?

 

For you "Land Lubbers", it's used to attach the tow ropes...............and although the angle of the picture may look like it's not centered......it was.