Bravo 1 Transom studs' sealant?

[tank1949]

I am rebuilding my boat's transom and have removed one Bravo 1 transom assembly, which had eight 7/16" studs. These studs have course threads screwing into the transom assembly and fine threads on the opposite ends for locknuts.Four of the eight 7/16" studs went all the way through the aluminum transom assembly and are exposed to salt water. The remaining four bottomed-out inside the aluminum transom assembly. My MC manual provides torque values of all eight studs but does not say what sealant is to use on the 4 bolts that go through the assembly and exposed to salt water. Any suggestions? It seems to me that aviation sealant would be find.

 

[Oshkosh1]

Why would sealant meant for aircraft flying in a dry environment be "fine" for a marine application?

Use marine grade 3M 5200...

 

[tank1949]

It stays tacky. 5200 is good too! Manual may call for locktite but I cannot find any mention of 5200 or other stuff.

 

[Bondo]

Ayuh,..... I put Perfect Seal on the threads, before screwin' things together,.....

Stops the bolts from corroding to the housin's,....

 

[Scott Danforth]

before aviation sealant was called aviation sealant.....it was simply called permatex #3.

Permatex #3 is what i have been using for decades. came out of early OMC, Volvo and Mercruiser manuals. (granted, they each call it something else, as well as state "can substitute permatex #3"

5200 is the wrong product in this application

 

[tank1949]

It stays tacky. 5200 is good too! Manual may call for locktite but I cannot find any mention of 5200 or other stuff.

Others have stated that perfect seal is the same stuff as P #3. THX...but I am not real sure that these 4 studs require locktite or similar. If these bolts come lose, water will come in via bolt hole. I cannot find anything in my MC manual on exactly what to use. Perhaps MC doesn't consider these bolts to be significant? THX!

 

[AShipShow]

On my rebuild I used loctite on the threads and then a couple thick coats of paint over the exposed studs... but then again, I'm in fresh water...

 

[Oshkosh1]

IF you're sealing them THROUGH the transom then 5200 IS what you want to use.

If you're just sealing the gaskets or threads then the red #3 is fine. It's little more than dyed rubber cement. I use it to hold gaskets on engines I build.

For everything requiring an RTV I use my industrial gun full of "The Right Stuff"...I use it like Franks Red Hot...

I guess I'm not clear on exactly what it is you're sealing up...

 

[tank1949]

IF you're sealing them THROUGH the transom then 5200 IS what you want to use.

If you're just sealing the gaskets or threads then the red #3 is fine. It's little more than dyed rubber cement. I use it to hold gaskets on engines I build.

For everything requiring an RTV I use my industrial gun full of "The Right Stuff"...I use it like Franks Red Hot...

I guess I'm not clear on exactly what it is you're sealing up...

The 8 studs have course threads that screw directly into the aluminum Bravo 1 transom assembly. I had to remove most of them from inside my boat because they had rusted to the transom's wood and glass. I could not get assembly off without removing studs from the inside of the boat. The rust had swollen between the wood/glass. I will have to replace the studs that are badly rusted. Therefore, when I install new studs into the aluminum Bravo 1 transom assembly and torque them, I'd like to know what is the acceptable MC sealant: perfect seal, aviation #3, 5200, Lockktite, etc. I realize that 5200 is the best sealant for the exposed studs part passing THRU the rebuilt wood or coosa board transom. This boat will be exposed to salt water.