Hello...sorry I missed this discussion earlier. Hopefully you solved your light seal problems and your camera is back on the 😎 "dark side." 😎 As for why the original seal material turned to goo in the first place, here is the answer: The original seal material was destined to become goo no matter what happened...it is the nature of this particular type of foam, but the environment it was in was helping to carve its tombstone with each passing day. The original foam was neither high quality nor expensive. It was cheap and it was plentiful, and let's not forget camera makers had to be mindful of their bottom line. Cutting costs on items like this allowed them to dedicate money toward more sophisticated research...the sort of research that expands electronic horizons and produces ideas. Wonderful ideas like digital cameras. Beyond that, it was very susceptible to damage from environmental and industrial pollutants. Interestingly, one of the industrial pollutants which may have caused rapid degradation of it was formaldehyde fumes or vapors. Chemists at more than one foam company have told me these fumes would accelerate the breakdown by large degrees. The manufacture of photographic film uses tons of formaldehyde. As a result, your original seal material may have been bought to its knees much quicker from the outgassing. Maybe this was more of a culprit in the case of cameras with film left in them for prolonged periods, but wait...the story continues. Formaldehyde has been used in building materials, adhesives, dyes, fabrics (especially synthetic permanent press fabrics), carpet manufacturing...even mouthwash. So, a camera left in a desk made of particleboard? Could be in danger, particularly if that desk was made in a country where particleboard construction is not regulated. A camera left in a closet? Could be in danger, especially if the closet is full of new clothes or was recently re-carpeted, or if it is a cedar closet and the cedar was applied to the walls with some forms of glue. A camera with minty fresh breath? I'm not even going to think about that one.
These are some of the reasons I've searched so long for foam products which have proven their longevity in the industrial world and why I will not use any formaldehyde-based adhesive. So, while it isn't easy to unscramble this egg...the other exposure to formaldehyde was the adhesive originally used on the OEM foam. Which, as I already mentioned, probably led us to digital cameras in the first place.
Jon
