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HOW TO REPLACE LIGHT SEALS WITHOUT USING FOAM STRIPS, MOVIE CAMERA STYLE


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<p >Disintegrating light seals are a fact of life with most cameras manufactured from the 1960's onwards. Here is a method I have used on hundreds of still cameras which is derived from my time repairing cine camera equipment. Arriflex, Mitchell and other film magazines use light seals made from lengths of wool, velvet or felt tape glued in place. This method stands up to the constant loading and unloading of the movie world often for years at a time. In your classic camera they will last forever.</p>

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<p >You will need a few common hand tools, some acetone, Bostic Clear Bond glue, Rubber Cement - I use Ados F2, 8-ply black wool (not acrylic!) and velvet tape. You will also need a well-ventilated space, plenty of time and old camera to practice on. Let's get started:</p>

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<p >1. Cut a piece of paper to cover the film gate and attach it with Sellotape making sure that all edges of the tape are sealed to prevent the ingress of the old foam when cleaning.</p>

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<p >2. Whittle down the end of a bamboo satay stick to make a suitable tool to remove the old foam seal material. (Special Tool #1) Unlike a metal scraper, the wood of the satay stick won't damage the paint in the channels or the channels themselves. Note the ashtray is used for acetone during cleaning. I don't smoke and I recommend that you don't either when using a flammable solvent like acetone!</p>

</p><div>00SVtw-110681984.jpg.b9958dd521c4c29529b3d7c63b759068.jpg</div>

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<p >4. Soak a cotton bud very lightly with acetone and run it along the channel. This allows Special Tool #1 to make a near-perfect job of removing the old foam seal material. Be very mindful not to use too much acetone!</p>

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<p >On newer plastic-bodied cameras use methylated spirits for most of the cleaning, only using acetone for the final cleaning of the light seal tracks. Even cameras from the late 1970's onwards use many plastic parts in their wind mechanisms and film counters, as well as plastic exterior trim. Over-liberal use of acetone can ruin them.</p>

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<p >For example, I instructed a friend of mine in this method of light seal replacement, but she used so much acetone that it migrated to the plastic shutter blades of the EOS film camera she was working on and glued them together! It was an early EOS and she, being a student, couldn't afford to have the shutter replaced, so that was the end of that camera...</p>

</p><div>00SVuB-110682584.jpg.baec35dbb10171da200ee877bbc24659.jpg</div>

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<p >6. Here are your replacement seals: 8-ply black wool and velvet tape. These are readily available from your local dressmaking supplies shop. Cheap too. A roll of velvet tape and some 8-ply wool will cost under $10 and you can do hundreds of cameras with this much material!</p>

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<p >Note the old door edge seal at the top right of the picture from the Pentax K1000. Top marks to Pentax for using a strip of felt which sits in a groove next to the hinge area. In this example I reused the felt seal.</p>

</p><div>00SVuK-110682784.jpg.a10da69dc62a4f4cde1a033d49ccb772.jpg</div>

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<p >9. Use the curved end of the paper clip to lay down a track of glue. Getting the amount right takes practise, but err on the side of caution and you will get good seal adhesion without having to much excess glue to deal with. You may need to practise this on a junk camera till you get your technique perfected.</p>

</p><div>00SVuV-110683184.jpg.8a604ee45980f8e3f541c109e0485746.jpg</div>

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<p >10. Stretch the wool and twist it to close up the weave and make it the same thickness as the seal channel. The amount of twist you put on the wool strand depends on the width of the seal channel you are working with. The narrower the channel, the more twist. Sorry I couldn't get a picture of twisting the wool and laying the seal in, but I only have one pair of hands! The flat back of the paper clip is very useful for setting the seal in place.</p>

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<p >11. Each time after touching the seal down with the flat back of the paper clip, clean the back of the paper clip in acetone and wipe it off on a tissue. Dip the back of the paper clip in acetone before putting it to the new wool seal each time - this makes it easier to move the wool to the bottom of the seal channel and gives you more time to work. The glue sets quickly...</p>

</p><div>00SVua-110683384.jpg.da95ea0f9d7b8228c73cc2b12fd1b30d.jpg</div>

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<p >14. Once the seal is in place all the way along the channel and you are happy with the way it is sitting, use some acetone on a cotton bud to remove the excess glue from the channel and the back of the camera. As per step 4, don't use too much acetone!</p>

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<p >Repeat all of the above on the top channel. The area where the counter reset latch is located on the top right end of the back requires you to set two seals - a long one from the counter reset latch to the left end of the body, and a short section from the counter reset latch to the right end of the body. It is actually quite easy to install. Just twist the end of the new wool seal strip and insert it next to the counter reset latch, hold the end down with the back of the paper clip, stretch the wool out and pull it down into the seal channel.</p>

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<p >After leaving the camera to sit for ten minutes so the acetone to boils off you can try closing the camera. Only leave it closed for about 30 seconds - just long enough for the seals to take a set from the film door. Then open the film door and using acetone re-set any parts of the wool seal that have lifted and clean any glue from the film door. Also clean any excess glue from the body.</p>

</p><div>00SVuf-110683784.jpg.08275f4e854d977114a3b06b476612a6.jpg</div>

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<p >15. Some designs have a large wedge of decayed foam in this area near the door latch. Clean it out and use a strip of velvet tape glued into the gap. The picture is of a Minolta Hi-Matic 7SII film door showing the velvet strip attached to the body near the hinge, and another velvet strip folded and glued into the end of the door. I painted the glue on the body and on the velvet strip using a cotton bud, then pushed the velvet strip in with a flat screwdriver blade so it folded as it went in. On the Hi-Matic 7SII the edge of the body is quite deep and acts as a "knife" when it closes, dropping between either side of the velvet strip, sealing perfectly.</p>

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<p >On the Pentax K1000 I re-installed the felt seal that Pentax wisely used to seal the door end.</p>

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<p >If the door edge seal near the hinge is made of foam, then cut a piece of velvet tape to fit the body and glue it onto the body with either Bostic Clear Bond or Rubber Cement. You may need to make the velvet strip narrower with a pair of scissors. It's best to put the door seal strip on the body if at all possible. That way the action of the door closing is just compressing the velvet. Attaching the seal to the door imposes a sliding action on the seal each time the door opens and closes. Still, you only have to re-glue it if it eventually falls off. </p>

</p><div>00SVum-110683884.jpg.77feef309f24306141a7aa8aeeed2af2.jpg</div>

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<p >This method is quite time consuming at first, but I can do light seals in an hour for most examples. Some cameras are more difficult as they have kinks in the light channels to allow the film canister to drop out - Nikkormats, Konica Autoreflexes, Minolta's, etc. This might add another ten minutes to the repair time as you have to manoeuvre the wool thread around bends in the light channel and sometimes peal off the leatherette and remove the film back latch mechanism to gain access to the seal area.</p>

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<p >The only camera I have ever had problems with using this sealing method was a Canonet GIII-17QL, where the lower film door seal is a wide strip of foam attached to the door. I overcame this by gluing another velvet strip on top of the first one to make up for the large amount of flexing on this door design.</p>

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<p >This is a repair method that can be considered "permanent." If done properly you will never need to do it again. It is also dirt cheap compared to foam light seal kits. I also find trying to manoeuvre pre-glued foam strips into narrow film channels an exercise in frustration. And to be quite frank, the results using foam strips are never as good. That's why Leitz used the glue and thread light seal method in the Leicaflex.</p>

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<p >Sorry about the pictures on parts 1. & 2. I forgot to resize them to 700 pixels...</p>

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<p >Peter</p>

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<p>Wow Peter, thanks! Even I can figure it out thanks to your clear pictures. If anyone wants to save this they can download a free utility called CutePDF Writer. It takes up very little room on your computer and it will convert any web page to a PDF document, pictures and all. Then ditch Adobe and get the free and much smaller Foxit Reader to view the doc. I did that and now have your excellent tutorial saved for future reference.</p>
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<p>Excellent step by step instructions, Peter. I've tried yarn, but found that because it does not expand like foam, it did not fill the channels as well as a properly sized foam strip that is compressed to fit in there and expands to fill them up. But the difference is mostly aesthetic, I'm sure yarn works just as well.</p>
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<p>Excellent! This may be the best illustrated explanation I've seen for how to correctly reseal older cameras that predate the use of closed or open cell foam, rather than using the bits of too-thick foam that can cause film doors to bulge from strained hinges and latch areas.</p>

<p>This really should be submitted as a photo.net article, where it won't be lost since forum discussion threads tend to drift into obscurity. This may serve as a useful reference for others since this topic comes up frequently.</p>

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<p >I'm glad you all found this useful and thanks for your kind words! I immensely enjoy reading all of your postings on Photo.Net, so it's nice to give something back.</p>

<p >August, the wool thread does have a degree of "spring" to it, so it is somewhat like foam but without the drawbacks. Gluing the wool in seems to stop loose fibres from drifting about. I've never had a "hair in the gate" from the wool thread on cine cameras using this method, whereas cotton thread seems to break up after a while and you get bits of flock floating around. With the sort of $/hour burn rate on a movie people get really annoyed over this sort of thing.Lex, I have used this method on plenty of modern-ish plastic-bodied Canon EOS's, Nikons and Minolta's too with no problems. However with thier fragile plastic hooks and eyes holding the cases together, electrolytic capacitors leaking corrosive material over the multi-layer, flexible (at least at first) circuit boards, lack of parts and unobtainable ROM update software as a private repairer I don't think anyone will be worrying about the repair of the stuff from that era for much longer...</p>

<p >How do I go about submitting this as a Photo.Net article?</p>

<p >Peter</p>

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<p>This is yet another example of the excellence of this forum for classic (and even non-classic) camera enthusiasts. Although I've never had any trouble using the first rate Jon Goodman foam kit and groove strips, and recommend them at every opportunity, this also is clearly an excellent and permanent method of light sealing, beautifully illustrated and explained. I have had one or two cameras that, when opened, have been treated by Peter's method, and I have not bothered to renew them with the foam kit, as they were still perfectly light-tight. It's good to have such an easy alternative in the camera repair toolbox.</p>
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