Reviving elastomers in a microwave!?!?

[averagebiker]

Morning,
I saw a mention of briefly microwaving elastomers in a cup of eater to revive them (restore shape and soften them).

Has anyone tried this? Did it work?

Tempted to give it a go!

Rich.

 

[Suprachrgd82]

The most common cause of elastomer failure is exposure to petroleum-based lubricants. Once the polymer is exposed there’s really no going back. Heat may make the elastomer temporarily pliable, but it will never regain its springy quality.

 

[Frankenorange]

 

[Baulz]

I remember our shop microwaving pro flex elastomers that went hard way back in the day but can't remember the actual process.

 

[bikeworkshop]

The plastics are breaking down, so as a rule any "fix" will be temporary.

 

[averagebiker]

The ones i have look as good as new but may have firmed up a bit? I obviously don't know what they felt like when they were new.
As I rebuild the "nearly NOS" fork my plan is to refit them with fresh lube and see how it works. If it seems too firm, trying the microwave trick to restore some "give" can't hurt. If it doesn't work I will just get fresh elastomers anyway.

 

[Uncle Grumpy]

The elastomers have started to degrade. They will get hot and might soften up but as soon as they cool again, they're back to firm.

I'd be worried that I'd heat them up to much and end up with shorter, fatter elastomers and less travel with each stroke.

If they're munted, you've got nothing to lose and you gain a story to tell next time someone asks. Keen to hear the real world results!

This reminds me of the story back in the BMX days of the 80s about Skyway Tuffs, and if you buckled them, you put them in the freezer and they straightened out.

 

[Suprachrgd82]

ProFlex elastomers were very unique. The originals were a foam-like material, highly aerated, that allowed for almost 100% compression. Shock travel was almost equal to the entire height of the elastomer stack. The new replacements are solid elastomer which only offer a fraction of the suspension travel which also becomes exponentially stiffer as it is compressed. To achieve "like new" travel and reasonable ride quality from a ProFlex, the best option is to look for a spring/oil damper from another ProFlex (Girvin or Noleen). Solid elastomers on the back of a ProFlex is more softail than FS.

 

[novocaine]

reason for degradation - loss of aromatics from the plastic (yes an elastomer in a bike was plastic, no natural rubber here folks, dinosaur extract all the way, drill baby drill) results in chemical bond structure and lattice changing, elastomer becomes hard.
stick it in the microwave 2 things happen, one those bonds open up with heat and everything becomes more pliable again (more room for the sneaky particles to get past each other), two some of those aromatics that were left behind run away too (so your microwave now smells like a dinosaur fart). wanna guess what happens when you remove more of the flex giving, loose bonded aromatics from the long chain that is a plastic? yep you guessed it, less flex. depending where they are in the chain, you end up with brittle (because there's a hole now you see) plastic eventually.

TLDR - dinosaur farts smell like plastic.

 

[FluffyChicken]

It only works if you stick a fresh egg next to them...