Renovating boat windows
➜
Dismantling and cleaning the window frames
B
efore dismantling
anything, lay all frames
face-down on a piece of
wallpaper and stencil around
them. Mark the stencil with
orientation and window number.
Note the difference in width
between the stencil line and
the frame itself. When you
eventually reassemble them you
will then have an accurate guide
to the original width, enabling
any necessary light clamping
to realign them while the butyl
is fresh, ensuring accurate
alignment of screw holes when
remounting back onto the hull.
This is particularly important for
larger frames.
For the next stage you’ll need
screwdrivers, plastic scrapers,
gloves, snipe-nosed pliers,
blades, butyl kit and work surface
protection. White spirit and meths
now became our best friend: they
are very effective. White spirit and
paraffin will not dissolve cured
silicone, but once most of the
sealant has been removed with
a blade they will soften the
remaining residue, making it
more susceptible to removal with
a blade/plastic scraper.
With the frames now free of
the boat, the real work began:
cleaning and disassembling them
prior to resealing the glazing. Our
aim was to ensure all surfaces
were clean and free of oil/silicone
so that the primer and butyl
sealant could bond properly to
both frame and glass. Cut into
the butyl all around the frame
perimeter on both sides with a
new Stanley knife blade. The butyl
Make sure you have screwdrivers, plastic scrapers, gloves, snipe-nosed pliers, blades, a butyl kit, a suitably
prepared work surface, hot soapy water, white spirit and a piece of wallpaper to hand!
Stencilling the frames with orientation and frame numberCutting into the old butyl with a sharp bladeSeparating the frame halves
which were held together
by fishplatesTOP TIP
The screw sockets, the old
screws and fishplates need to
be clean and salt/silicone-free to
create a leak-free seal when
reassembling. Hot soapy water
followed by gentle abrasion
can be used to clean these.Cleaning the glass and edge using hot soapy water, white spirit and Cif
may be very hard, so white spirit
can help soften it. Do this several
times to full depth so the glass is
released from the frame.
Our channelled frames were
in two halves held together by
fishplates – thin strips of metal
located in the bed of the channel
held by screws through the frame.These need to be released to
get the frame apart. After
mounting the frames in a
workbench, the fishplate screws
need to be removed from at least
one side – not necessarily easy
as a result of the unholy marriage
of stainless steel screws and
aluminium frames!
Take care not to damage the
anodising, distort the frame or
break the glass when clamping,
so use an old cloth for protection.
Carefully clamping the frame
enables you to get real pressure
and turning force on the
screwdriver without the head
jumping. Pre-treatment with
penetrating oil and hot water
may help to dissolve the salt/
oxide build-up and expand
the aluminium.
Next we separate the two frame
halves. Clamp just one end of the
frame, so the other end is free to
move. Wrap a piece of strong, thin
material (eg polyester) around the
end of a preferably rounded filler
knife, then insert this between theframe and glass at the end of
the frame. Using a mallet, gently
knock the two halves apart, taking
care not to distort anything.
To clean out the frame
channel use an old, long, narrow
screwdriver to dig out the old
butyl, then plastic scrapers and
finally a Scotchbrite pad together
with plenty of white spirit. Clean
the glass and its edges. As our
frame progressively became
cleaner I used a combination of
washing in hot soapy water, Cif,
white spirit and finally meths to
ensure a clean surface. I also tried
using a chemical that is supposed
to dissolve cured silicone, but in
my experience it was either totally
ineffective or had an effect of
about 1 out of 10.
The hull window opening
needs to be as clean as the
window frames, so I used a variety
of tools and several home-made
perspex scrapers (which proved
invaluable as they didn’t scratch)
in conjunction with white
spirit and Cif.