My interest in film cameras lies in putting the old things back to use, so when I got my Ricoh 500G which was in dire need of light seal replacement, I took the opportunity to figure out how to jimmy-rig some light seals for just a few bucks. Here's what I came up with.
1 Sheet Black Self-stick felt ($1 at the craft store)
Cotton Balls (not pictured)
X-acto Knife (not pictured)
Small dish of water
Tiny Scissors from a Nail Kit
(Weird anatomical camera drawing not required, I just wanted to draw and it ended up being helpful for me to discern where to place the new light seals.)
Step 1: Removing the Nasty, Sticky Stuff
Don't forget to scrape away the gunk from the other edge of the camera opposite the back. (That sounds strange, doesn't it?) The last photo of this step shows what I'm talking about, though (albeit upside-down -- I'm not always the most coherent worker!).
Step 2: Placing the Seal, Pt 1
(1) A diagram I made based on the degrading foam seals. The orange shows where the new seals will be placed based on where the old ones appeared to be.
(2) Cut the sticky-back felt to size. I held it up to the camera back for reference.
(3) Peel off some of the sticky back and begin pressing it into the camera back.
(4) through (9) Use the x-acto knife and little scissors to clip away space for the plastic back that the film rests against as it's going through your camera. It took me a while, wittling away at it with my tools! I trimmed mine flush with the edge of the film rest.
Step 3: Placing the Seal, Pt 2
(2) On the top area, press the felt down and depress it around the viewfinder area, feeling for the ridges.
(3) Use the exacto knife (and small scissors if needed) to trim away the viewfinder area. You can also remove some of the felt to the left, but be careful not to take off too much.
(4) Run the exacto knife through the corner and cut away any bits of felt that are hanging around there.
(5) Everything should now look like this.
Step 4: Placing the Seal, Pt 3
(2) Cut away two small bits of sticky felt for the left hand back of the camera. I put tacky glue on them to help them stick.
(3) Pressing one of two glued pieces into place.
(4) Letting the two glued pieces sit to try. I picked away the extra tacky glue with a toothpick.
(5) through (7) The finished product.