Transom redo: 3m or silicon?

[Beercap]

I've heard various opinions on the subject of what to dip the bolts into when replacing the transom. What are the pros and cons to 3m and silicon putty?

On a side note should the exterior have wood on it as well with carriage bolts? It seems like bolting through exterior and interior would cause multiple points for leaks.

Thank you much!

 

[Captain Ahab]

I assume you mean 3m 5200 and vs Pure Silicone? 5200 is an adhesive and sure sticky - once it is on it does not come off. If all you are looking to do is waterproof then the silicone will works fine

You do not need wood on the external part of the transom - and unless you are putting holes below the waterline I would not worry about leaks - just waterproof to prevent transom rot

 

[MrSimon]

3M 5200 is awesome. I use it to dip all my bolts and rivets in and have never had one leak.

 

[PSG-1]

I wouldn't trust silicone. It does not properly adhere to metal, and UV light will break it down. 5200 is the better and more durable fix.

 

[kfa4303]

+1. NEVER use "silly-cone" on a boat. That is the tell-tale sign of a Mickeymouse job. 3M 5200 is great stuff and you only need to apply it to and through-hull fittings such as the hardware used to mount the transom to the hull. Make sure you only use sealed, non-pressure treated wood along with stainless steel hardware as well.

 

[FishingBuds]

5200!

 

[Beercap]

AWESOME! Glad to hear the news about the 5200 and the exterior. I used Home Depot plywood on my first attempt like a noob and sure enough a void cracked! This time I'm using marine grade Douglas fir.

Last time I used a calking gun and 5200 on stainless steel bolts. Can I reuse those bolts and just dip any areas where the 5200 wore off? Or should I start with clean bolts?

Thanks guys, I'm hooking up a Honda 15hp 4 stroke and want a transom worthy of this beauty 8) !