White "powder" in pickup cavity?

It occurs to me that this foam under pickups may be a guitar maintenance and repair headache a few decades in the future. Some kinds of foam deteriorate over time into a nasty tarry goo. I first learned that with a set of expensive American Optical hearing protectors that I bought in 1965 to wear while shooting guns. By the mid '70s, the soft black foam under the plastic seals around the ears had completely turned into sticky goo. Ruined the protectors. Hammond Organ replaced the felts that cushion the stopping of the keys at top and bottom with urethane foam around 1965. Later Hammond organs have had much trouble with this, as the foam turns into that goo and it attacks the wiring to the keys, corroding it away to a powder that crumbles. It's a terrible job removing gooey foam from a Hammond keyboard, and much worse if not done before the wires start breaking. We (or our kids and grandkids) may have similar issues with pickups in the future.

A good point, Ric. I've have the same happen on everything from moderately expensive items such as my fave Sennheizer headphones (+15 y.o.) to the cheapies like foot pads on tape dispensers (then the sand leaks out ..). The grade and type of foam really matters, as rubber foam sulphur content => eventual hardening and attacks on electronics, while environmental exposure turns most synthetic foams back to the goo +solvents from whence they came. There are high quality rubber foams, but I'm not sure how or where to find them. I don't trust Allparts to sell the right stuff. High quality rubber weather stripping might be good in terms of resisting environmental breakdown, but even that is designed with a limited life in mind.

And it's really too bad, as new, dense memory foam actually works better than a pair of springs in many pup mounting applications, as the foam inhibits pup rattle. Some years ago, a number of guitar makers "innovated" a three point 'bucker mounting system (Tele bridge still has!) that took care the play issue, but that never caught on. I think nobody seemed to care, the aftermarket compatibility was not good, and why add $0.25 to the cost for no measureable gain in market share.

I might be possible to put the foam inside a "bodybag" to contain it later upon deterioration. But what is flexible, long-lasting in impervious to sulphur and solvents? Given that latex rubber and plastics also age or will dissolve, the only thing I can come up with is a "natural" membrane that hard when dry and will not prevent the transmission of HIV. :?

So who knows something about foam rubber chemistry, and can point us to the right stuff? Wonder if the "Tempurpedic" memory foam lasts.

Another thought: Maybe flat springs (think lipstick pups) instead of coil springs is the answer to the anti-rattle issue. Beryllium-copper.