"Wm Watt" wrote in message
oups.com...
On Sep 10, 12:00 pm, "Toller" wrote:
My Potter 15 rudder is made of 4 pieces. The top is a solid core about
10"x15", with two pieces of plywood screwed to it on either side
measuring
10"x30". The solid blade mounts between the plywood, below the solid
top.

Those side pieces are called the rudder cheeks. I've replaced mine on
a 21 foot mahogony strip saiboat. They get a lot of stress when
running before the wind with waves comming under the transom and
trying to change your course on you. I just used ordinary fir plywood
without any voids in it. It should be thick and stong. The thickness
might be determined by the hardware used to hang the rudder off the
transom (pintles and gudgeons) although you can rout the plywood to
accept narrow hardware.

Rudder Cheeks eh? What is the piece between the cheeks called?
Mine are 3/8" ply, routed down to 3/16" at the hardware.

What did you put on them to waterproof them?

On Sep 12, 1:17 pm, "Toller" wrote:

Rudder Cheeks eh? What is the piece between the cheeks called?
Mine are 3/8" ply, routed down to 3/16" at the hardware.

What did you put on them to waterproof them?-

Paint. For the edges anything you have handy will do. They are not
going to be under water. If I were doing it today I'd spread polyester
resin along the edges where it can soak in to keep moisture from
penetrating. Epoxy, polyurethane varnish, or even linseed oil if
that's what you have at hand.

I'd also smear polyester resin on any places which would chafe, for
example if the tiller is inserted between the cheeks (I don't know
what that's called), or the rudder rotates between the cheeks ("kick
up" rudder) . Polyester is good for abraision resistance. I use it on
my home built boats where parts might rub. I coated the inside of a
dagger board trunk with it. Just the resin, no fibreglass
reinforcement. Or epoxy if that's what you have.

"Wm Watt" wrote in message
oups.com...
On Sep 12, 1:17 pm, "Toller" wrote:

Rudder Cheeks eh? What is the piece between the cheeks called?
Mine are 3/8" ply, routed down to 3/16" at the hardware.

What did you put on them to waterproof them?-

Paint. For the edges anything you have handy will do. They are not
going to be under water. If I were doing it today I'd spread polyester
resin along the edges where it can soak in to keep moisture from
penetrating. Epoxy, polyurethane varnish, or even linseed oil if
that's what you have at hand.

I'd also smear polyester resin on any places which would chafe, for
example if the tiller is inserted between the cheeks (I don't know
what that's called), or the rudder rotates between the cheeks ("kick
up" rudder) . Polyester is good for abraision resistance. I use it on
my home built boats where parts might rub. I coated the inside of a
dagger board trunk with it. Just the resin, no fibreglass
reinforcement. Or epoxy if that's what you have.

I have epoxy (and linseed oil and polyurethane varnish) but hesitate to use
it since it is not UV stable.
I have never used polyester, but have heard it doesn't adhear worth a damn.
That is not your experience I take it?

Toller wrote:

I have never used polyester, but have heard it doesn't adhear worth
a damn. That is not your experience I take it?

A lot of things - including the 40' ply and fiberglass Newporter
ketch - were made with polyester resin. Does it stick as well as
epoxy? No. But it isn't exactly easy to get off either.

When I had a sizeable sailboat I used it (with fiberglass) on anything
I made of ply - trunk cabin deck, dog house, hatchs, etc. - and never
had any adhesion problem in the 20 years I owned the boat.

Consider the number of cars that have had dings filled with Bondo.
Bondo is polyester resin and talc. Have you seen many chunks of Bondo
along the roadside?


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dadiOH
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"dadiOH"
Consider the number of cars that have had dings filled with Bondo.
Bondo is polyester resin and talc. Have you seen many chunks of Bondo
along the roadside?

Alas, yes.

"dadiOH"
Consider the number of cars that have had dings filled with Bondo.
Bondo is polyester resin and talc. Have you seen many chunks of Bondo
along the roadside?

More than I can remember.

You can spot a "Bondo Job" from a 100 ft in a snow storm.

Lew

"Toller"
I have epoxy (and linseed oil and polyurethane varnish) but hesitate to
use it since it is not UV stable.

Almost nothing is UV stable, including paint, wood, epoxy, varnish,
polyurethane, and wood.

However, sealing plywood edges with epoxy, lightweight fiberglass (with the
appropriate weight fabric and a curve that it can take), covered with primer
and paint, is as good as you can plan for. As long as you maintain the paint
for appearance, it will probably serve to preserve the epoxy & fiberglass.
I figure that a decent job of it, aside from direct scrapes and dings,
should be good for 5-10 years of regular use.

If you're looking at the leading edge of a kick-up rudder that meets the
ground routinely, you'll need more than one layer of glass, and regular
touch-ups of paint.