Do I dare use 5200??

[bruce v]

[QUOTE=Suijin;2615730]5200 gets a bad rap. It's an amaaaaazing sealant because it's an amaaaazing glue. I just stripped my whole deck, 32 years old, everything bedded in 5200. Found one small leak and that looked like installation error. If you want something to not leak, use 5200.

That said, that part being above the waterline and not actually subject to a tremendous amount of force except perhaps laterally when in a very heavy seaway, I don't think it needs 5200. It's all about the mechanical fasteners.


I would consider replacing the wooden standoff block unless you're wedded to the aesthetics of it. You could shape similar out of G10 or some other composite and never have to worry about it again. As for a backing plate, I would go with aluminum plate or G10. Bed the plate with caulk, then bolt up the assembly.

So you say. 5200 is exactly what you said, a sealant glue. It will bind so securely fiberglass will tear and wood will separate before the bond gives. In places where you do not have concern about replacement, 5200 might be your choice. However, anything that move and wears over time and will require replacement will have to be restructured. That is why they made 4200 and 4000. Also in places where you don't want bonding and are not exposed to the sun's UV rays (joint between wood and steel plates) I would use butyl tape (30 year life span). Looks to me that the steel and wood bond to the top of the rudder are not in need of gluing so the best sealant would be butyl tape. Just my humble opinion - use dome at the top edge of the bolt too as it will seal those holes also.

[Siberian Sea]

I love this classic style of rudder design, I wish my vessel had this system. No matter if it was me I would replace the small wooden shim located outside under the rudder bracket that supports the rudder with a larger one in order the spread the stress over a larger area. You could easy triple the size of this and still keep it very attractive looking. On the inside I would use some heavy marine grade plywood enclosed with fiberglass to the hull. Try to spread load over large areas. Use a good marine sealant such a Sikaflex or 3M 4200. You can use 5200 but as there might be some desire to remove the assembly at a later time

[kclancy]

Originally Posted by Orion Jim

It looks as though the upper assembly is essentially a pillow block while the shoe must hold the weight of the rudder at the base. Hard to tell from the pictures.
Use a real backing plate not some starboard. Stainless, G10, or bronze. 5200 should be your last resort, 4200 or 4000UV would be fine. You have a great boat if it is maintained properly

What thickness of G10 is appropriate for use as a backing plate?