Building a new rudder

Hi guys

I have a 38 ft sailboat with a skeg hung rudder. There's rust oozing out of the rudder. The old rudder is filled with "mud" (a mix of polyester and sand most likely) and is hard as a rock. I can, of course, start digging into the rudder but that is going to be a very destructive and labor-intensive process. I think I might have more fun and get a better result if I make a mold of the old rudder and build a brand new rudder.

I'll lay up the mold by hand but I think it might be fun to get into some (epoxy) vacuum infusion for the new rudder (just to have a bit of fun).

What type of foam is recommended?

Would the preferred method be some along the lines of what's outlined in the below links? aka fill the two halves with foam and then adhere those thogeter.

Making a New Rudder for Passport 40 Sail Boat | Sand Cay Club http://sandcayclub.org/2014/06/12/making-a-new-rudder-for-passport-40-sail-boat/
Making a Passport 40 Rudder | Sand Cay Club http://sandcayclub.org/2014/07/28/making-a-passport-40-rudder/

 

For a one off replacement part I would not bother with a mold. A rudder is a fairly simple shape that can be duplicated in block foam accurately by anyone who is even remotely handy (enough to make a mold AND replacement part). The addition of the hinge hardware will be much simpler, and the whole thing glassed, vac-bagged, faired, painted, and back on the boat by the time you've got an acceptable mold built to then start working on your actual part.

If you want to engage in an exercise in mold making, then have fun. But if you just want a new rudder its not necessary.

 

I want to make the mold because I think it'll be a fun project

 

fun... I see you've never done fiberglass before. lol

 

haha, I'd say I've done a fair bit