and removing light seals in film cameras.
June 3rd 2016
Locate a clean ,ventilated work area that is well lit.
amount Naphtha, mineral spirits or your favorite solvent that is plastic
A pair of technicians
Kimwipes (or paper towels)
Technicians work mat
Toothpicks (both square and round)
Q-tips with paper sticks
Adhesive Delay agent:
Sanitizing Gel 70% Alcohol (additive free)
Water ( recommended)
Handling the smaller foam pieces is
easiest with a pair of tweezers.
You never need to hurry.
important and time consuming work is removing the old seals. Focus on
clean, 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 adhere to that sticky, gooey residue that was once
a quality light seal. Proper installation will give you thousands of
light tight exposures.
Removing Old Seals
some of your solvent (1oz) in a small container.
The easiest way to apply the solvent is
to take tweezers and put the points into the solvent. Then squeeze the
points together, then relax them a little and withdraw the tweezers.
Capillary action should have the solvent in between the points.
Look carefully at the tweezers points while they are in the solvent. You
will notice the distance between the tweezers points (as you
squeeze and release them) dictates how much solvent they will hold.
Practice a few times until you can easily fill the tweezers points.
You can easily
direct a drop or less of solvent exactly where you want it.
Apply even smaller amounts by dipping
toothpicks into the solvent.
camera models from about the late 60's on, used light seals with the
After applying solvent to the old seal and
waiting 10-20 seconds. Many times, with tweezers you can
get under the foam seal and
get to the tape then just peel the entire
seal strip off in one piece.
Door channel seals vary in width and a custom tool
can easily be made to help remove and push the old foam out. Take
a Q-tip (cotton swab) and cut off one of the tips, then using small
needle nose pliers squeeze the end carefully until the width fits the
door channel. You can easily cut that end with an Exacto to a shape that
works for you.
The first seals I remove are the door
channels. Fill your #5 tweezers points with solvent and
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
residue will just pile up in the channel and can be picked out and wiped
out. Wrapping a Kimwipe around the straight tweezers points and
dipping that in solvent works quite well in the channels also. We know
of technicians who prefer an old toothbrush and would brush out the
softened foam. Clean. Clean. Clean.
Now 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, clean the mirror cushion area.
Here you must be extremely careful.
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 damaged focusing screen or mirror so
it would look like new.
Carefully pick and scrape at the remaining cushion towards the lens
opening. Some mirror
cushions are installed with peel and stick
adhesive. Sometimes it will just peel off.
Be rested and relaxed.
You do not have to hurry the install, but be
All I am trying to do here is prepare you for a
somewhat precise service that generally requires 10 minutes or
less. Installing seals go very fast after the camera has been cleaned.
You will be surprised how quickly you will finish. If you continue
installing light seals, say for your friends film cameras, you will be
quite proficient after 5 to 10 installations.
This is a technical
however not a difficult task
You should have steady hands and not be frustrated
easily working with small objects, tools and tweezers.
As far as the difficulty level working on photo equipment and
using a 1 - 10 scale,
installing seals is a 3.
The skill level required goes up if you are removing covers.
You would know your skill and ability better than anyone
It is very difficult to damage your camera performing this
I have trained many photo technicians and for the most part, women had
better hand eye coordination, learned quickly and became proficient
faster at camera service than men.
installing light seals?
I recommend starting with the shorter seals first, such as the door
hinge seal. This is a rather short piece and can be handled easily.
I do not recommend starting with the mirror cushion seal
The replacement seals are cut to exact lengths. Stretching of
the seals during installation and around corners will result in some
left over at the end which can be trimmed with an Exacto knife or razor
Because of the type of adhesive used, some door hinge, mirror
cushion and other seals do not stretch during installation. Typically,
the thinner the width of the seal, the easier the material can be
stretched and or torn.
wetting agents as a adhesive delay.
When installing seals that already have the adhesive
applied requires a different technique than applying seals with no
Delaying the adhesive from setting /sticking immediately upon contact is a must.
You have less chance of a successful install if do not use a
wetting agent. You have
a limited time before the seal has to be placed and positioned.
Alcohol has the shortest working time, hand sanitizer is the
longest and water is in between.
I personally found water is the best. It does not
react with the adhesive and gives a workable handling time before the
adhesive bonds. I checked
the adhesive bond, by applying water to the adhesive and then applying
the seal material to smooth surface plastic laminate and another sample
to painted steel. After the wetting agent dried all foam was damaged
somewhat when removal was attempted.
We found three ways to delay the adhesive,
2) water / moisture
3) hand sanitizer, alcohol based with absolutely no additives, no
fragrance, no moisturizers , ect
Preparing your equipment.
Remove all the old seals and spotlessly clean where
the new seals fit.
Installing the door channels can be the most
challenging. When installing the door channel seals, always start
at the door hinge side and work towards the latch side of the camera.
Many ways of applying the door channels or any seals for that matter
will work, however what I am just trying to relay what worked best for
If I can see the upper door channel completely, fine.
If not, I loosen the top cover screws first and check again. Most of the time the top cover will not have to be removed
but sometimes yes. I check the bottom door channels for corner damage,
remove the bottom cover if necessary. If the door closes and latches
unlatches easily usually that means the channels are OK.
If any of the door channels show a little damage, all you need to
do is stretch the seal a little bit and it will fit easily in the
USCamera Tech Note.
Camera manufacturers install light
seals with the covers. Many times, when the top and bottom covers are
installed, it will obscure a clear view of the door channel making it
more challenging to install those seals.
Over the life of many film cameras, they are
dropped. Sometimes at the bottom cover corners. This can damage
the door channel at that location. This will constrict that
channel some making it a little more difficult to install the seal.
Never try and straighten the channel, it will break, see below.
I cannot say this loud
enough. RESIST the
temptation to insert a screwdriver or ? and carefully attempt to
straighten the bend in the door channel.
Many camera bodies are cast aluminum and some are plastic. You
will break off the casting before you
believe you have put any pressure on the channel. Lesson learned from
If working on an RB / RZ back and insert, I remove the
top and bottom covers.
Using water as a wetting agent.
Holding the seal with wet fingers, I remove the
backing and apply water liberally (not soaking) to the seal by dipping
clean fingers in a glass of water and gently guiding / carefully pulling
the seal around / through my wet fingers.
Colorado has a dry climate.
I can take a wet seal and place it, remove it and place it again
without damaging it.
However after the second time if you have not placed it correctly, rewet
the seal. The results I describe are from testing seal placement on
clean door channels of a test camera body.
After wetting, I found I had about a minute or so, to place the
seal in position before the adhesive started to become tacky. If I
placed the seal in the channel and removed it, water would need to be
re-applied as the looses moisture when contacting the channel.
Installing the seals.
As I said at the start, beginners should install short
seals first, the channel seals and the mirror cushion last. It is of
course entirely up to you.
I am assuming you have confirmed the channels are not
damaged. Also, you have loosened screws or removed covers to have full
access to the channels and other areas requiring seal replacement. You
should have the tools you need.
Below I am explaining how I install seals. Remember
how you install the seals is up to you, the following is what works for
I place the equipment flat on a tech work mat so is
does not slide or move around easily. I take a square toothpick and trim
it so it perfectly fits the door channel of the camera I am working on.
Make a couple of these. I have several toothpicks, q-tips I have made
before. I also use pointed bamboo stick a lot to push the seal or hold
it in place
Lay out the light seals.
I am right handed. For this seal piece, I rotate the
camera so the hinge is on my left.
Select the top door channel seal (which is now on the
bottom) starting at the hinge side, with backing on the seal, I
hold it up to the channel and size it from the beginning of the channel
to the counter lever opening. Then I cut that seal length. The remainder
of that seal will fit the rest of the top channel.
I wet my fingers, remove the backing on the short seal
and moisten it, making sure that the edges of the adhesive are wet. Then
I hold one end of the seal with tweezers and place it in the channel,
holding the end I just laid in place with a toothpick, I lay the rest of
the seal in position. Again
with my fingers wet with water, I remove the backing from the remaining
top channel seal and moisten the seal. Then starting at the other side
of the counter lever opening and place the end of the seal at the in the
beginning of the channel and press about 10 -15 mm of the seal in place
with a trimmed toothpick or bamboo stick. Then I hold the other end of
that seal with tweezers and guide the remainder of the seal in place.
Then with the trimmed toothpick or bamboo I carefully press the seal
into the channel. Now | perform the exact same service installing the
bottom channel seal. I install rest of the seals used on the back cover.
Then I close the back cover to seat the seals in position. Last I install the mirror cushion. Now I open the back cover
and leave it open until the seals have completely dried. In the Denver
area about 4 - 6 hours.
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 or applying a just the right 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.
the USCamera Team