A new ringer for me: 1967 Webster Office Phone based on ITT base

[TelePlay]

The plastics were obviously heat damaged at some point or did not hold up well in aging: I could crack the remaining pieces in my hand!

Plastic gets hard over time due to degradation of their plasticizers and colorizers, some due to breakdown during normal aging and others due to exposure to environmental factors.

The result is the plastics always get harder, become brittle and are prone to easy breakage.

[RDPipes]

The box was in good shape actually. Packed with no padded and plenty of loose space. The plastics were obviously heat damaged at some point or did not hold up well in aging: I could crack the remaining pieces in my hand! Any thoughts on the " ringer" and how and why it was attached to the network the way it was?

Not a clue sir, I know little about 500 series sets or later, that be a question for Poplar1.

[RDPipes]

Plastic gets hard over time due to degradation of their plasticizers and colorizers, some due to breakdown during normal aging and others due to exposure to environmental factors.

The result is the plastics always get harder, become brittle and are prone to easy breakage.

Yes sir, I know that, just didn't know how brittle they were.

[TelePlay]

Plastic gets hard over time due to degradation of their plasticizers . . .

This not only applies to plastic but also rubber. Anyone who worked on older phones, especially the WE 302 and its contemporaries, has had coiled/straight rubber handset cords AND rubber conductors not within a rubber sheath that have hardened to the point that any movement of the cord or conductor would cause the rubber to break and crumble.

Loss of the plasticizer chemicals within the rubber compound due to degradation over time (and sometimes out gassing) leaves the rubber first stiff, then hard and finally so brittle it crumbles with the slightest movement.

I've tried but never found a way to reverse the stiffness.

There is no way to recover a rubber cord that's cracking and crumbling other than coating the crumbling conductor with liquid electrical tape (inside housings and handsets - not a pretty solution but it stabilizes crumbling coatings and covers bare wires).

[allnumbedup]

I once soaked a hardened straight Brown WE handset cord I intended to use on my soft plastic mahongany 500 in "Leather CPR" I figured it was safe for leather and advertized as made of 100% cosmetic ingredients so wouldn't do much harm. I checked back after 5 days and yes the cord softened a bit but the the rubber grommet that inserts into the handset completely dissolved to brown mush. too bad so sad.

[TelePlay]

I researched this a few years ago and the "best" method I found was using wintergreen oil, a salicylate that is or is similar chemically to plasticizers used when the rubber item was first made.

Original rubber plasticizers incorporated into the pre-molded rubber item are in these classes "Plasticizers used in rubber coatings include phthalates (DOP, DINP), adipates (DOA), citrates (ATBC), and phosphates, which increase flexibility and durability." Organic compounds that are "esters" have names that end with "-ate" as does methyl salicylate (eg. wintergreen oil). Esters are organic compounds known for there fruity odors, such as banana, pear, etc.

To restore a stiff cord, the plasticizer has to deeply penetrate the rubber, different application then mixing the plasticizer into the rubber formulation before forming the item. Seems the alcohol is the "carrier" that drifts the oil into the rubber item. The alcohol out gasses leaving the salicylate in place.


"Wintergreen Oil & Alcohol Solution (Most Effective):

Mix 3 parts isopropyl alcohol with 1 part methyl salicylate (wintergreen oil). Soak the rubber in a sealed container for 1-7 days. This mixture restores flexibility to old, brittle rubber."


"Wintergreen oil (methyl salicylate) acts as a highly effective swelling agent and plasticizer for rejuvenating, softening, and restoring hardened or old rubber parts. It is commonly used in a mixture with isopropyl alcohol to restore flexibility to rubber items like carburetor boots, gaskets, and seals, often by soaking them for several days."


"Key Details on Using Wintergreen Oil for Rubber:

Method: The most common approach involves soaking hardened rubber in a mixture of 1 part wintergreen oil to 3 parts isopropyl alcohol.

Effect: It penetrates the rubber, replacing plasticizers lost over time, making it soft and pliable again.

Safety & Precautions: While effective, it can cause excessive swelling if used improperly and may make the rubber sticky or gummy if over-treated. It is recommended to test on a small, hidden area first and use appropriate personal protective equipment, as discussed in this YouTube video."

https://youtu.be/O4j7G9ry6uk

I didn't try it, I think the cost of about $4 an ounce was the deciding factor (4 ounces in 12 ounces of alcohol per cord application - if 16 ounces is enough to totally submerge the cord).

One caution is that all rubber items are not the same, what may work for one cord may dissolve another cord.

Another caution is bending the stiff cord to get it into a container in which it can be totally submerged for days without cracking the cord.