Cutting and fitting Bungs
Bungs or Plugs are the traditional way to cover the heads of
fastenings on Wooden Boats.
Even today, with all the epoxy putties
that are available
there are still advantages to using wood.
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most obvious one is when
the surface is to be given a
natural finish, such as varnish.
However, even where the
surface is to be painted, the
wooden plugs have the advantage that they are less likely to fall out
they will expand when they ‘take up’ thus tightening their grip on
All this countersinking and
plugging might seem like a
lot of tedious work but it is imperative to protect those
much as possible.
Drilling and bunging is also
an ideal way to cover up
blemishes and filling knot holes.
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It is possible to
purchase ready cut
plugs and they do come in a variety of woods.
However, they can work out expensive if you need a lot of them and they
will not necessarily match the wood you have used.
Besides, you will most likely have lots of off cuts lying about which
might as well be used up, so make your own.
Try to use off cuts of the same wood as that to be plugged and chose
pieces which have a close straight grain.
It is possible to cut plugs with a hand drill and a
I have done it.
But, you will get a better, cleaner plug if you use a drill press and a
plug cutting tool.
For best results and fit, buy the cutter and countersink bit together
‘Fuller’ cutters are worth the extra cost if only for the
chamfer which they cut on the top end, this makes the plug easier to
These cutters are not easy to sharpen.
If you plan to do a lot of plugging, it’s worth spending a little
extra on the extra-hard cutters that are designed for hardwood, even if
you are cutting mainly softwoods, they will stay sharp longer.
If you only need a few plugs, they can be cut into any board which is
thicker than the depth of the cutter.
The plugs can then be tweaked out with the blade of a screwdriver.
However if you are going to be using any appreciable quantity, then
are best cut in strips.
To make joined up strips of bungs, cut the wood into lengths along the
The strip should be approximately 1/8 inch, 3mm wider then plug or the
same width as the outside diameter of the cutter.
And it should be about 1/32inch, 1mm thicker than the full cutting
of the cutter.
Clamp the strip onto the drill press and cut the plugs as close
The idea is to be left with a row of bungs still attached to a thin
of wood which, can easily be broken off as they are used.
Using this strip method will also make it easier to align the grain as
you fit the plugs.
Use a fast drill speed, too slow will burn the sides of the plug but
don’t use too much downward force as this can leave the sides
Before you start
bunging its worth going around all the fastenings to give them a final
make sure they are tight.
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you begin fitting the
plugs, the main thing to
remember is to keep the grain aligned with that of the wood being
They should be lightly tapped
in place using a light
wooden mallet. Don't hit it too hard as the plug may be crushed.
A well fitting plug should fit
so well into the holes
that it is not necessary to use glue or paint to keep it in place. And
will become even tighter when they absorb moisture and swell.
However most builders use some
Whatever you use try to keep
glue to sides of bung and
not on the bottom as this will end up fouling the head of the screw or
Use a small brush or piece of
stick to paint on the glue
rather than just dipping it into the glue.
Where the wood is to be
finished off with varnish it is
not uncommon to just dip the bungs in old varnish before tapping
And where the surface is to be
painted the bungs can be
set in paint of a similar color.
Shellac (de-waxed garnet
grade) has been much neglected
as a sealer and adhesive it is ideal for securing bungs.
It can be mixed 50-50 with red
lead paint or white lead
Of course you can use any
waterproof glue but it is best
if it is one which isn’t hard when set as this could cause problems
So now you have a boat bristling with protruding bungs and the
glue has had
time to set.
The easiest method I have found to
trim the plugs is with a
‘flush-cut’ saw. If you are careful you can get them level enough
to finish off with the sander.
The usual method though, is to use a very sharp chisel to
shave off the
excess, a crank handled chisel is best.
You have to be
careful and watch how the grain
runs so as not to cause the plug to chip off below the plank
Don’t try to chisel off straight from the base but pare off
progressive cuts to determine the run of the grain.
When it is time to finish and fair the hull the most common
method is with a
However, if the ‘glue’ used on the plugs is at all hard you
could end up with the bung being left proud.
A better method might be with a plane with the blade set very
Some builders use an angle grinder or other electric finishing
The cutting, fitting and finishing of wooden bungs is regarded
by some as
being a tedious and messy procedure.
But it is one of those tried and tested methods which will
repay the effort
in the long run.