Black Silicone for Rudder Replacement - Feedback Please -

[Moose]

Well I have a new rudder assembly on it's way but completely forgot about getting some sealer like 3m 4200. My idea is to use some rtv black silicone. It's waterproof, oil proof, can handle high temps., and from what I've been reading on the rudder repair threads 4200 is less adhesive than 5200 so removal down the road is easier. Black rtv would work in that way also. I'm a mechanic by trade and have used the black rtv silicone alot and I can't see any reason why it wouldn't work just like the 3m 4200.

Please give me some feedback on this. I want to do the rudder repair this weekend and would like to know if the black silicone is a big mistake.

[bens250ex]

I have used both in different applications I would prob opt to use something like roof/gutter sealant instead of the rtv silicon

[Salty87]

only if it's rated for below the waterline. you can find 4200 and 5200 at home depot.

[bens250ex]

Yes 5200 can be found at some home depot. Walmart also sells a product sim to 5200 fast cure, you can find it with the rest of the boat supplies I tried it out on something and it acted just like 5200 when cured

[Moose]

Just picked up some 5200 from depot. They didn't have the 4200. The rtv black silicone is not rated below waterline or marine use but it has been used on outdrives below waterline with no leaks. It is pretty tough stuff can use in oil, coolant, or water applications. Resealed my thermostst housing with it and it will last longer than the thermostat. My thought is it's tougher than other marine grade sealers I've used just not sure why below the waterline would matter.