by GreenLake » Sun May 20, 2018 10:29 pm
My process was to make head and blade from the same blank.
Shaped the foil while head was still attached (which gave me a nice flat area to clamp the piece to the bench for shaping).
Sheathed blade in glass - that's a step you need anyway. (Keep the blade vertical and wrap a single piece of cloth from the front edge). This layer is merely for scratch protection, not so much for strength.
I sheathed the head (while still connected to the blade if memory serves) so that the blade would be as wide as the head (and to get correct separation for the cheeks that way). Tricky part is how to support the work piece - I think I used something like nails and/or wire, suspending it after wrapping. Or may have drilled one of the holes already and used that. (More likely, because coating the inside of all holes with epoxy is a thing and can be taken care of for the ones that got a nylon bushing. Those wouldn't need to be drilled out wider nor filled completely with epoxy).
The inside of the cheeks would have to be glassed before assembly - that's a single layer, not wrap around. If you have the work space, you do it at the same time as the blade.
The outside of the head and cheeks can be done at the same time after they've been glued together. Depending on the bracket for the pintles, you may need to cut a channel as they are unlikely to span the cheek. If you do that before doing the outside glass, you can make that a bit deeper and wider (gentle shoulders). Then glass everything (cheek and head - one side at a time), using a dual or triple layer where you expect more stress, otherwise, just a single rather light layer for scratch resistance.
Incidentally, none of that work will be very time consuming compared to fairing the blade and painting. That level surface prep usually takes half the time on a project like that; the "structural" work is almost easy by comparison, no matter how you do it.
I didn't worry about the edges of the cheeks - they are not very exposed in normal use and simply sealing them in epoxy is sufficient, no need to stress getting glass there. Same, really for top and aft edge of rudder head. (The front got glass because of the way I wrapped the piece). Same for top end of blade or bottom end of head: after cutting them apart (and while glueing on the cheeks) I used some of the epoxy to seal the new edge.
For the pivot hole and tiller bolt hole I used nylon bushings, but for throughbolting the pintle brackets I oversized the holes, filled them with epoxy and then drilled them again - that way none of the bolts can wear away the epoxy sealing the holes.
As mentioned, sanding and fairing the blade took the longest. The rough blank had some flat spots. I've learned a new technique, which is to use a spreader with V notches to spread the fairing compound. You then sand the ridges to the template, and in the next pass, just fill the valleys with a straight spreader. Much faster and more accurate than trying to build up thickness any other way.
Did coat the fairing compound with neat epoxy when done - and cut the tip off the finished rudder (and glued it back on): that way, if the tip gets damaged and becomes waterlogged, the moisture cannot travel up the full blade.
Anyway, I find that being a bit organized about what parts can get epoxied in the same phase of your project makes for an optimized work flow.
~ green ~ lake ~ ~