Well for a start nothing
looks worse than a keel streaked with rust and full of pockmarks.
Especially if you decide to
sell the boat.
But apart from the appearance,
if rusting is allowed to
continue unabated the rust flakes will keep expanding, falling away and
exposing more of the iron which, will in turn rust and fall off and so
ad-infinitum while there is still iron to oxidize.
And because rust expands any
that is allowed to form
behind the paintwork will cause the paint to flake off.
that iron keel won’t disappear overnight, and there is much that you
do to slow the process.
And there is a lot to be said
in favor of the cast iron
It is one of the cheapest and
safest materials to cast a
keel from, it has none of the toxic problems that are associated with
smelting and while way cheaper than many of the more exotic materials
does a perfectly adequate job.
This is not the easiest or cleanest job in
the world but it is worth the
effort just to keep your pride and joy in good condition.
And at least you won’t be doing it on a daily basis like those
Merchant seamen or yore, constantly chipping rust and repainting their
However, before you start chipping that keel rust, decide on
how you are
going to treat the clean metal and have the paint or whatever ready.
That clean metal will very
quickly begin to
develop a new layer of
rust, so coat it as soon as possible.
There are several ways to clean off the old keel
Just remember that for the protective coating to be successful
you need to
get down to clean metal before it is applied.
Chipping hammer or cold
chisel; Begin chipping off all
the scale, then use a wire brush and sand with coarse paper until
to clean, bright iron. Then use a fine sandpaper to finish.
Angle grinder and discs; Best
to chip off the worst of the flakes first to prevent too many bits
Sandblasting the rusty keel;
While this may be a very efficient method it is very messy and does
specialized equipment. And
you may find that your
boat yard doesn’t allow sandblasting, because of the
Shot blasting is carries the
same problems as sandblasting.
Needle gun; These guns can
usually be rented from a tool rental shop. They work by driving a set
of steel needles into the surface of the rusty
keel. Driven by either compressed air or electric drive, they can do a
good job of getting into the pits and roughing up the surface ready for
While clearly the best way to treat keel rust is to clean the entire
Sometimes though, it is neither possible nor desirable, because of the
problems involved, patching up may be the only option.
And often the keel wont have rusted evenly there will be sound areas
surrounded by pits.
If you are going to patch make sure you get all that rust out of the
before over coating.
And don’t forget the bottom of that rusty keel and
to replace the bungs covering the keel bolts.
I am perfectly aware that the majority of Wooden Boat aficionados are sensible folk. However, I need to point out that I am an amateur wooden boat enthusiast simply writing in order to try to help other amateur wooden boat enthusiasts. And while I take every care to ensure that the information in DIY Wood Boat.com is correct, anyone acting on the information on this website does so at their own risk.