|
Installing Light Seals
The most important aspect of
installation is Clean. Clean.
Clean. The old residue from
the door channels, mirror cushion area, door hinge area and anywhere else you
are replacing the seals. The finest adhesive in the world will not stick to that
sticky, gooey residue that was once a quality light seal. Proper installation
will give you thousands of light tight exposures.
I have found the best solvent/cleaner is
Naphtha or mineral spirits. It is readily available, loosens and dissolves the
old adhesive and foam easily. Along with solvent, it is nice to have a pair of
quality #3 or #5 tweezers, q-tips, toothpicks, Exacto knife, dental pick and
Kimwipes (or paper towels).
Locate a clean and ventilated work area
and put some solvent in a small container (1-2oz).
The easiest way to apply the solvent for
me is to take my tweezers and put the points into the solvent. Then squeeze the
points together and withdraw the tweezers. Capillary action should have the
solvent in between the points. Now you can easily direct a drop or less of
solvent exactly where you want it. Practice a few times until you can easily
fill the tweezers.
Apply even smaller amounts by dipping
toothpicks into the solvent.
The first seals I remove are the door
channels. I fill my #5 tweezers points with solvent and carefully moisten the
foam in the channels. You must be more careful around the counter actuation
lever opening (upper right hand corner door channel on many cameras) as you do
not want to apply solvent to the interior of the camera.
After a couple of minutes the residue
can be easily removed by pushing it into a pile with a toothpick. The residue
will just pile up in the channel and can be picked and wiped out. Wrapping a
Kimwipe around the tweezers, dipping that in solvent works quite well in the
channels also. I know of technicians who prefer an old toothbrush and would
brush out the softened foam. Clean. Clean. Clean.
Next I clean the door hinge seal area.
Here you can lightly moisten q-tips to apply solvent and then wipe and clean
away the residue.
Last, I clean the mirror cushion
area. Here you must be extremely careful.
If the focusing screen is easily removable, remove it. Make sure that no pieces of the old cushion fall onto the focusing screen. If
any anything contacts the focusing screen it will most likely damage it
permanently. We have never found any way to clean a light seal foam damaged
focusing screen so that it would look as new.
I will carefully pick and scrape at the
remaining cushion towards the lens opening. Many cushions are installed with
peal and stick adhesive. Sometimes if you are lucky, it will just peel off.
The replacement seals are cut to exact
lengths. Stretching of the door channel seals during installation and around
corners will result in some left over at the end which can be trimmed with
scissors, an Exacto knife or razor blade.
If the foam breaks as you are stretching / installing it, don't worry.
Just start applying the foam again right where it broke. You will
not be able to tell it ever broke after the foam seats in position.
Some door hinge, mirror cushion and
other seals can not be stretched during installation because of the type of
adhesive.
I would say for a beginner the door
hinge seal should be installed first. This is a rather short piece and can be
handled easily.
If you are having problems keeping to
the seal from twisting when placing it in the door channel, try a placing a
small amount of rubbing alcohol in the door channel with a pair of tweezers then
place the seal in position. When the alcohol evaporates the seal will stay in
place as the alcohol as no affect on the the staying power of the adhesive.
Last but not least, through experience
we have found some seals would like a little adhesive keep them in place.
Goodyear Pliobond is great contact cement for this purpose. Remember you are
attaching small pieces of foam to a precise instrument. A toothpick works great
for applying a small amount of adhesive to the foam or the location where the
foam will be placed. Never try to apply adhesive to any area near the
focusing screen. Always apply the adhesive to the foam first. Should adhesive
somehow get on the screen it will permanently damage it.
Good Luck,
Gray
|
