Good finish for wooden rudder / daggerboard?

Thread starter #1
Ok, am getting ready to make a new daggerboard and refinish the original wooden rudder. Both are mahogany. Looking for opinions / advice as to what products to use for finishing and how to apply / how many coats. Spar urethane / varnish? Good brands? Brands to avoid? Thin first couple coats?
 
#2
I sanded mine down to the wood, and then gave two coats of clear epoxy before finishing off with a couple coats of marine spar varnish. The epoxy was the stuff cedar strip boat builders use, i'ts thin and very clear. The reason for using it first is it's very,very hard (it will stand up to the usual dings and scrapes) and will completely waterproof the wood. You need to apply varnish afterwards because varnish gives good UV protection. Epoxy can't withstand UV rays on it's own.
 
#4
I agree with Ritchie. I usually put on one coat of epoxy and then sand it. After that I put on one or more coats of varnish. Ritchie may be right about two coats. I may try that next time.

I use the epoxy to cut down on the number of coats of varnish I need.

I use West Systems Epoxy. I use the fast hardener, but they have a clear that is supposed to show through clear. I don't think it matters on a rudder or daggerboard, the clear is better for lighter grain woods.
 
#5
Whose Ritchie? :confused:;)
I use U.S. Composites 635 thin epoxy resin, with the slow hardener. Very clear, no blush. You could use the medium hardener, but you'd probably need to wash the blush off between coats, and also prior to varnishing. The slow hardener doesn't blush at all.

Randy Ricchi (Rick-ee)
 
#6
Whose Ritchie? :confused:;)
I use U.S. Composites 635 thin epoxy resin, with the slow hardener. Very clear, no blush. You could use the medium hardener, but you'd probably need to wash the blush off between coats, and also prior to varnishing. The slow hardener doesn't blush at all.

Randy Ricchi (Rick-ee)
Ooops! Sorry about that, I should have quoted you. Sorry!
 
#7
Here's info from a person who makes the boards. I'v done this twice with good results.

Finishing instructions for unfinished mahogany blades

 Blades are supplied sanded to 100 grit. This
may seem a little rough, but fear not. To avoid
blotchiness, do not sand any finer before the
following steps.
 Use good marine varnish. I have had
excellent results with Interlux products, which are
available from most marine supply stores. Epifanes is
also excellent, maybe even better if you use it right,
but it’s more expensive, harder to find, and harder to
work with. Do not use the goop sold at hardware
stores, even if it says ‘marine’ something on the can.
The real cost of the job is the time you put into it.
My time is worth quality materials; yours should be
too.
 Use either a good quality badger hair brush
made specifically for varnishing, if you are willing
to take the time to take care of it, or disposable
foam brushes if you aren’t. The only kind of foam
brush worth using is called the ‘Poly-Brush’ – it has
a wood handle and a very small-cell gray foam head.
Most Sears hardware stores, marine supply places, and
good paint stores stock these. The same manufacturer
makes another item called a ‘Foam-Brush’ which has
coarser foam and doesn’t work very well. The foam
brushes with plastic handles sold in packages at
discount places are WORTHLESS. I can buy a whole case
of foam brushes for the price of one good hair brush,
so that’s what I use.
 Hang the parts from a ceiling, closet pole,
etc., at a comfortable level for you to work at. Try
to do this indoors if at all possible. Dust can be a
pain, but even worse is stuff like wind-blown dirt,
cottonwood fuzzies, and bugs. Wet varnish seems to
have a magnetic attraction for the deerflies and
mosquitoes where I live.
 Thin the first coat by at least 50%, using
the manufacturer’s recommended thinner. Put it on
with the grain, brush it across the grain to work it
into the wood, and then go over it very lightly with
the grain to get rid of brush marks and bubbles.
 After first coat is dry, hand sand using 150
grit paper until surface is smooth and all raised
fibers have been removed.
 Thin the second and third coats 25%, fourth
coat 10%, subsequent coats only if necessary to brush.
On unfinished wood, eight coats will give you a
pretty decent base, which if not abused will last an
entire season. Use progressively finer sandpaper
after each couple of coats, ending with 320 grit.
 Before each season, or if the finish is
damaged, lightly sand and recoat with full-strength
varnish. If cared for, this finish should last for
several years before it will need to be stripped and
redone.
 
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