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Removing Installing Light Seals

Removing Installing Light Seals | Film Cameras USCamera

USCamera Light Seal Instructions
Removing Installing Light Seals

Installing light seals requires patience and with detailed USCamera professional instructions, it could not be much easier.

Some customers started a new business by installing light seals in friends’ cameras and as they gained experience, they started servicing equipment for stores in their area. Others purchased collectible equipment needing seals at bargain prices and are able to replace the seals then re-sell the equipment for a profit.

Do be realistic, open your camera, and look at the door channels on the body. Most channels are less than 2 mm wide and you will be working with 2 foam strips to fit in those channels. Also, the door hinge seals and mirror cushions are other seals you will likely replace when installing one of our kits.

We truly enjoy film cameras.  We have installed thousands of seals in almost every camera and accessory that required replacements. You can gain from that experience.  Plus we use real sample cameras for measurements. That is the only way to make sure our kits fit perfectly. Removing Installing Light Seals

Light Seal Kits

See all light seal kits currently available, start here.

Light Seal Placement Guides

We are revising and adding new light seal placement guides every week, go here.

Placement guides can help, especially when the old light seals have already removed.

Our placement guides show you where to place each seal included in our kits.

Everyone has camera phones now. I encourage taking pictures of your existing seals, as a reminder of what seals you need to install and where the seals are placed in your camera.

Tool List

Solvent – A small amount Naphtha, mineral spirits or your favorite foam solvent. I prefer MEK though great care must be taken when using that solvent.
Tech Note. Some of the newer film cameras use plastic body castings.  Make sure your foam solvent is plastic friendly.

A pair of technicians quality curved or straight tweezers. Makes handling smaller pieces of foam easier.
Dental pick
Exacto knife
Kimwipes (or paper towels)
Small brush to apply adhesive delay
Technicians work mat
Toothpicks (both square and round)
Q-tips with paper sticks

Adhesive delay agent:

Hand Sanitizing Gel 70% Alcohol (like Purell additive-free)
Rubbing alcohol

Organize before you start.
Locate a clean, ventilated work area that is well lit.

Handling the smaller foam pieces is easiest with a pair of tweezers.

The most 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.

Put some of your solvent (1 oz) 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 the tips 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.

USCamera Tech Note. Several Minolta film camera models from about the late 1960s and on used light seals with the adhesive applied.  After applying solvent to the old seal, wait 10-20 seconds and many times with tweezers you can carefully 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 a small pair of needle-nose pliers squeeze the end carefully until the width fits the door channel.  You can easily cut that end with an Exacto knife to a shape that works for you.

The bamboo tool we send with every kit also works well.  Use some sandpaper or a fingernail file to sand down the blunt to a narrow chisel point until it fits the body channels. Then it can scrape or push the  foam into piles.

Removing Installing Light Seals | The first seals I remove are in the door channels on the camera body

Fill your #5 tweezers points with solvent and carefully moisten the foam in the channels.  You must be extra 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 or the bamboo tool.  The 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 the points in your solvent, also works quite well in the body channels also.  We know of several technicians who prefer to use an old toothbrush to brush out the softened foam.  Remember clean, clean, clean.

Now clean the door hinge seal area.  Here you can lightly moisten q-tips to apply the solvent and then wipe and clean away the residue.

Last, 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 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 a peel and stick adhesive.  Sometimes it will just peel off the cushion frame.

Prepare yourself

Be rested and relaxed.

You do not have to hurry the install, but be prepared.

All I am trying to do is prepare you for a somewhat precise service that generally requires 10 minutes or less.  Installing light seals goes 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 friend’s film cameras, you will be quite proficient after 5 to 10 installations.

Qualify Yourself

This is a technical task however not a difficult task to accomplish.  You should have steady hands and not be frustrated easily working with small objects with tools and tweezers.  As far as the difficulty level working on photo equipment, using a 1-10 scale, installing light 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 else.

It is very difficult to damage your camera by performing this service.

I have trained many photo technicians and for the most part, women had better hand-eye coordination, learned quickly, and became proficient much faster at servicing photo or imaging equipment than men.
Removing Installing Light Seals


New to 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 first.

The replacement seals are cut to exact lengths. Stretching the seals during installation and around corners will result in some leftover foam which can be easily trimmed with an Exacto knife or razor blade.  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.

Understanding wetting agents as an adhesive delay

When installing seals that already have the adhesive applied requires a different technique than applying seals with no adhesive.

Delaying the adhesive from setting/sticking immediately upon contact is a must. You have less of a chance of a successful install if do not use a wetting agent because of the limited time before the seal has to be placed and positioned.  Alcohol has the shortest working time, hand sanitizer the longest and water is somewhere in between.

I personally found water is the best and Purell a close second. Both did not react with the adhesive and gave a workable handling time before the adhesive bonds. Purell makes easy installation where some seals were nearly impossible to install as it needs to be slid into place.  Camera manufacturers install many seals to single parts that are part of an assembly, then put it together as a unit.

I check the adhesive bond, by applying water or Purell 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.  The damage was enough that a replacement seal would be required.

We found three ways to delay the adhesive from the setting:

1) alcohol – more on that shortly

2) water/moisture

3) hand sanitizer (Purell), alcohol-based with absolutely no additives, no fragrance, no moisturizers, etc.  Any additives will prevent the adhesive from bonding.

Preparing your equipment for new seals.

Remove all the old seals and spotlessly clean where the new seals will be placed.  Look down in the door channels, with a magnifying glass if have too and make sure they are spotlessly clean.

Installing the door channel seals 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 me.

Also, 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 it does.  I check the bottom door channels for corner damage and remove the bottom cover if necessary.  If the door closes and latches and unlatches easily this usually indicates the channels are ok.  If any of the door channels show a little damage, just stretch the seal a little bit and it will fit easily into the damaged channel.

USCamera Tech Note

Camera manufacturers install light seals before the covers are installed.  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 incur impact damage 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 in this sentence. 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 experience.

If working on an RB/RZ backs and inserts, I remove the top and bottom covers.

Using water to delay the adhesive

Holding the seal with wet fingers, I remove the backing and apply water liberally (but 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, re-wet 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 it loses moisture when contacting the channel.

Installing the seals

As I said earlier, beginners should install short seals first saving the channel seals and the mirror cushions for last. However, it is of course entirely up to you.  Also, you have loosened screws or removed covers to have full access to the channels and other areas requiring seal replacement.  You should also have the tools you need within reach. You will also want to confirm the door channels on the camera body are not damaged.

Below I am explaining how I install the seals.  Remember, how you install the seals is up to you, but the following is what works for me.

I place the equipment flat, on a tech work mat so the equipment 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 them.  I have several toothpicks and q-tips I have made before.  I also often use pointed bamboo sticks to push the seal or hold it in place.

Layout 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.

Note. Whether installing channel seals on the camera or the back cover, always work from the hinge end towards the latch end until the seal is used up.

Removing Installing Light Seals | Keep your fingers wet

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 I place the end of the seal at 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.  Now with the trimmed toothpick or bamboo stick I carefully press the seal into the channel.

Next, I perform the exact same service installing the bottom channel seal and also install the 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, this is about 4 – 6 hours.

Using Purell to delay the adhesive

Everything above applies concerning the installation of light seals with the exception of how Purell is applied to the seal and application area.  I found it easiest to use a small brush (for example, nail polish brush size) to carefully paint the Purell on the application area and apply the seal.  Some installers say they have found it easier to also apply a brushstroke of Purell to the adhesive on the seal itself. Remember you are installing the seal on a fine instrument and do not need a lot of Purell.  The more you use the drying time increases.

When using Purell in the Denver area, the average drying time is about 24 hours.

Model Specific Use of Purell

It is almost indispensable when installing the door hinge seal on the Konica C35 and Auto S3. Really helps when sliding that seal under the plate.

Through experience, we have found some seals would like a little adhesive to help keep them in place. Goodyear Pliobond is a great contact cement for this purpose.  Remember, you are attaching small pieces of foam to a precise instrument.  A toothpick works great for applying just the right amount of adhesive to the foam.  Always apply the adhesive to the foam first.

Never try to apply adhesive to areas near the focusing screen.  Should adhesive get on the screen it will permanently damage it.

Your comments and questions are always welcome.

As always …………good luck.

The USCamera Team

Removing Installing Light Seals Film Cameras USCamera

Customer Comments on Issues During Install

Comments (28)

  1. Lydia L Perez December 12, 2019 at 5:49 AM Reply

    Why don’t you have a video? I live in a tropical climate island and I think water could cause mold. For me it is easier to learn from seing. I will try to follow instructions. Thanks

    1. Gray April 20, 2020 at 12:29 AM Reply

      We are working on those. I will send you a link soon. Yes, high humidity will cause mold to grow in the foam. It will also rust and corrode parts of your camera internally. Use air-tight containers with a desiccant inside.

  2. cibone January 13, 2020 at 2:40 PM Reply

    Most helpful, thanks. I am waiting to receive my Mamiya C330F viewfinder foam kit from USCamera. This will be the first time I have installed new seals/foam. Does the viewfinder foam kit come with adhesive already applied i.e. peel off strips and then apply?

    1. Gray April 20, 2020 at 12:21 AM Reply

      Thanks for your comments. Yes the viewfinder foam kit does have the adhesive already applied. Just remove the backing and press into place. Gray

  3. Rick Ramser January 18, 2020 at 4:02 PM Reply

    I ordered the light seals do you have any videos showing installation
    Thanks Rick ramser

    1. Gray April 20, 2020 at 12:19 AM Reply

      We are working on those. I will send you a link when those are posted. Gray.

  4. James Wilkins April 16, 2020 at 12:14 PM Reply

    Very thorough, thanks. I use bamboo skewers and small pieces of paper towel soaked in either naphtha or rubbing alcohol which I press into the channel with the skewer and push it along the channel making sure I engage the corners. As long as it comes out black I change to a fresh piece of paper towel for the next run and so on until it comes out clean. Then I inspect it with a magnifying glass in sunlight to make sure. Occasionally black paint is rubbed off in small areas. I paint that with Kodak Brushing Lacquer no. 4-dull black but I am not sure that step is necessary?

    1. Gray April 16, 2020 at 3:12 PM Reply

      Touching up with flat black lacquer is not really necessary but certainly makes for a nice finishing touch. Gray

  5. Tyler April 26, 2020 at 9:21 AM Reply

    I ordered a few seal kits from you all – quick question, does it matter if I use 99% isopropyl alcohol vs 70% Purel you recommend? Just being cautious as I do not want to damage anything.
    Thanks – Tyler

    1. Gray April 26, 2020 at 10:17 AM Reply

      99% is a bit much. Use 50% alcohol and you will be fine. Gray

  6. Dusan Maletic May 2, 2020 at 5:34 PM Reply

    Couple of observations that may help from my installation experience. I used rubbing alcohol as wetting agent, it worked excellently and just as needed, about a minute of working time which is enough. The most challenging bit was preference of the foam material to naturally curl toward the side with the adhesive, be prepared to deal with it and that in the corners , because of this effect, foam might want to naturally spiral-twist. Instructions are for the full installation of all the seals at once. If not in rush as I was not, installation in related pairs of foam strips may be easier. I installed them in pairs, leaving camera closed for about an hour and than went to the next pair, this helped press seals in by the camera as fast as possible after placement and time to be fully set before proceeding. Excellent product.

    1. Gray May 3, 2020 at 9:36 AM Reply

      That is a great way to apply the the install job to your style of working. Excellent! I am sure you were successful. Gray.

  7. Frank DiMaulo August 9, 2020 at 1:40 PM Reply

    I’m replacing the mirror cushion on my Pentax MX. Please end me a link as well when available.

    1. Gray August 9, 2020 at 4:33 PM Reply

      We stock a mirror cushion kit using foam with the adhesive applied here https://uscamera.com/product/pentax-mx-mirror-cushion-set/. We also make a mirror cushion without adhesive here https://uscamera.com/product/mx-original-style-mirror-cushion/. Good luck, Gray.

  8. TheStreetShooter August 31, 2020 at 9:08 AM Reply

    I will need light seals for a Nikon EL2. From what I have read online regarding the kit details, the mirror bumper is 2mm in height and the door seal is 1mm in height. Is that correct?

    1. Gray August 31, 2020 at 11:23 AM Reply

      For the Nikon EL2, the door hinge seal is 2mm thick and so is the mirror cushion. Good luck with your install. Gray

  9. Assaf Gavra September 23, 2020 at 2:29 PM Reply

    Do you already uploaded a video with instructions ?

    1. Gray September 23, 2020 at 3:03 PM Reply

      We have some videos on camera and lens service. At this time no light seal installation videos. Gray

  10. Niall Rooney December 7, 2020 at 4:37 AM Reply

    The top channel on my fujica stx-1 has a metal projection for detecting the back is closed, do I leave a millimetre or so gap in the seal?

    1. Gray October 29, 2021 at 1:46 PM Reply

      That is the counter actuation lever. You do not want to cover the lever or the opening with foam. Let me explain. You want to install the seal right up to the start of the opening and begin again on the other side of it. To measure the foam length required, I use a piece of solder or thin wire, anything like that will work. The length of foam you need is from the start of the top body channel seal at the hinge end to the start of cutout. Solder works best for me. I place it in the channel then I put a dent in it with tweezers when it reaches the lever cutout in the casting. Hope that helps. Good luck.

  11. Michael Douglas Malloy December 31, 2020 at 6:47 PM Reply

    If you cannot provide a video the next best thing would be some step by step photos. I look at the camera stripped down and I don’t know which foam piece to put where. The package you sent contained zip instructions, nada, nuttin’. Thanks for the pointy thing though. I bought 100 of them at Walmart for $.89.
    I’d like to SEE a method. If I’m able to identify which strips go in the tiny slots in the body. I’d like to know how to get them there without getting glue all over the place.

    1. Gray October 29, 2021 at 1:24 PM Reply

      Odd, we ad an info sheet with every kit shipped. To help you we have light seal placement guides for most light seal kits we sell. The Mamiya M645 guide is online here https://uscamera.com/mamiya-m645-placement-guide/ For installation and removal help go here https://uscamera.com/removing-installing-light-seals/

  12. Bud Sisti March 30, 2021 at 4:53 PM Reply

    Hi – I just completed the seal installation on my Mamiya Press 23. Your tips were invaluable, since I’m a rank amateur at this. Since I find written instructions easier to follow, I felt no need for a video, and found your instructions to be well-written and very comprehensible. Thanks! However, this was an full afternoon project, NOT ten minutes, and I wouldn’t want to do this for a living!

  13. Graham May 19, 2021 at 5:56 AM Reply

    Nice instruction I like the wet fingers!! Just ordered a kit waiting pensively to do this task.

  14. Vincent August 5, 2021 at 3:08 PM Reply

    I ordered a light seal kit for a Nikon FA and installed the foam with great success. Thanks for the instructions!

    1. Gray September 22, 2021 at 12:26 PM Reply

      Thanks for your comments.

  15. Christopher May 7, 2022 at 7:20 PM Reply

    Any instructional videos for yashica mat 124 g light seal installation?

    1. Gray May 8, 2022 at 9:11 AM Reply

      Thanks for contacting me. Sorry, no videos on light seals at this time. We do have removal and installation instructions here https://uscamera.com/removing-installing-light-seals/. For the light seal placement guide for that Yashica model, go here https://uscamera.com/uscamera-light-seal-placement-guide-yashicamat-tlr/. If you have any questions, you can call me anytime. Gray

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