OT What can I use to clean & restore old rubber with?
I'm going to ask the "experts" out in PM land.
I have a couple of old "toy" parts made of rubber that is old. They are dirty and slightly hard from setting in a metal box in a hot attic for 60 years. I want to clean them up the best I can and maybe restore some of the oils in the rubber that has been lost over the years. I suspect the rubber is Buna N, started out as a 40 -50 Durometer in hardness, now about 80-90 Duro. How bad would I mess them up using a "Armo-All" tire cleaner on them?
Silicon based lubricant has worked for me on rubber seals on ammunition cans.
A product called "rubber rejuvenator".
Kinda pricey 15yrs ago, now its probably 4 times as much.
When most rubbers harden, they also become subject to cracking, due to a chemical change in the crosslinking of the molecules.
I don't think that can really be un-done, so don't expect too much.
We used to use a rubber cleaner on tape recorder pinch rollers etc that smelled powerfully of phenol. It may be around still. But it cleaned off "perished" rubber, leaving the good that was underneath. I don't think anything really puts back the original springiness
The good news is the metal box probably kept the ozone off them.......
There are tyre treatments used to soften rubber for motor racing; 'Grip' is one trade name that I remember.
If you only want a small quantity, the model car racers use a similar product. Most model shops will have this in small containers. Ask for 'tyre additive'.
The active ingredient is a chemical; DEHP? that is actually a plasticiser used in the rubber manufacturing process. Some of the products out there use Salicylic Acid (Oil of wintergreen); stinks and is mostly banned at race meets because of toxicity. I would avoid this.
Clean with whatever works to clean, but silicone spray, silicon dielectric, whatever silicone is a wonder for rubber. I soaked some rubber bungs from my 1970 car in silicone spray over 20 years ago. They were hard as a rock. They softened right up and are still that way. My process is to soak them in a pan for a few weeks in the spray then rub the grease on them before they go into service. Obviously yo don't want toys greasy, but you get the picture.
Years ago we used a product called Fedron to recondition typewriter rollers. I Googled it and it is still available. We never found anything that would work better.
Laquer thinner works miracles on old rubber. Liberally soak a rag with automotive grade Laquer thinner and scrub the surface of the rubber. The thinner will dissolve the surface of the rubber while you scrub leaving a new looking finnish. When you are finnished scrubbing with thee thinner, wash the rubber with a mild soap and warm water to remove any remaining thinner.
Brake fluid, It has a rubber preservative in it. Works great and is cheep.
Throw Žem in the washing machine, 60° and a phosphate based washing detergent. I often do this to restore hardened and dirty bellows from motorcycles. It works quite well most of the time. A friend of mine used it to resoften a window frame for his oldtimer, it too werked very good.
Yaw gave me some ideas to try,