soften hard rubber

Discussion in 'The Garage' started by Beezer, Feb 22, 2013.

  1. Beezer

    Beezer Long timer

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    sooooo... teach an old dog a new trick. I recently ran into a formula for softening age hardened rubber... couple ounces of wintergreen oil in a pint or so of xylene. I just did some intake boots & they went from rock hard to like new flex in 24 hours. I am astounded at how well it worked. the wintergreen is supposed to have a natural plastisizer in it called meythyl salicylate. the test bits did not swell up noticeably and are still pliable after a couple days sitting on the bench. I put another set in mix yesterday & they show improvement, but not as dramatic as the first set. I intend to leave them in until tomorrow & see if they continue to improve. It's the same mix though, so maybe some fresh materials would speed things up.

    I got the oil from a local health food store, another source is homeopathic medicine. I hear that sports medicine uses it too.
    #1
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  2. Shadow 9er

    Shadow 9er renegade

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    That's a great tip! Thanks!
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  3. disston

    disston ShadeTreeExpert

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    It would be a really great tip if the results last. We can often restore the looks of rubber but then it goes back to it's aged appearance after a month. The treatment is needed again. Please report if your method seems to have longer lasting results.

    Terrific tip if it stays soft.
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  4. Beezer

    Beezer Long timer

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    so.... it's about 3 weeks since I made the original post. I also treated a 2nd pair of intake boots, and today I installed them. the first set I did had some small cracks (before the treatment) so I used the better set. anyway, all the boots are still soft as when they came out of the mix.
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  5. Gramp-Z

    Gramp-Z Been here awhile

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    A great tip ! Now if I can remember it for the next time I need it . :gerg
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  6. Gonzodog

    Gonzodog Been here awhile

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    That will work with synthetic rubbers used in the fuel system. Other natural rubber type compounds like tires, etc will be excessively swollen by the xylene.
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  7. zap2504

    zap2504 Dave E.

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    Also (from previous posts):
    "With nothing to lose, I immersed them in lacquer thinner and checked them twice a day. The things swell up and you would swear that they are ruined, but they shrink back to normal in a few days. Some guys also use wintergreen available at drug stores and make some sort of brew mixing it with the solvent. I just use the lacquer thinner until the boots soften enough and then soak the boots in the wintergreen for a day. As they start to shrink, the wintergreen sucks in to the rubber. The wintergreen at a cheaper price is also known as Thor Tire Prep #12 and available at kart shops to soften racing tires."
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  8. ttpete

    ttpete Rectum Non Bustibus

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    The wintergreen oil also is great for use on badly rusted fasteners. We used it on flange joint bolts on steam lines.
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  9. Beezer

    Beezer Long timer

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    bump,,,,


    about 10 weeks now & the test boots are still soft. the other set is on the bike & running fine
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  10. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

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    Cool tip, thanks for posting!
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  11. Beezer

    Beezer Long timer

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    almost 5 months now..... test parts still soft :evil
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  12. Beezer

    Beezer Long timer

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    over 2 years... the test boots still soft & the bike still working. I also softened a rubber diaphragm from a pump by rubbing it with just the oil. took a couple days but worked good
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  13. beemerkid

    beemerkid Do you ADV

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    Right on!
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  14. Maoule

    Maoule Been here awhile

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    I'm still working on a formula to get my soft rubber hard....:jack
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  15. cagiva549

    cagiva549 whats a cagiva

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    A 9 dollar harbor freight heat gun does a pretty good job too . SEYA
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  16. k-moe

    k-moe Long timer

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    Until the parts cool.
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  17. cagiva549

    cagiva549 whats a cagiva

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    That's the whole point , you want them soft and easy to install then locked in place until the next time it needs service . I don't want everything soft and rubbery on my bike . I remember the days of spitting the carb off if you had a backfire on the old smokers and they were easy to work on . SEYA
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  18. Beezer

    Beezer Long timer

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    uuuuuhhhhhhhh...... by soft, I mean nearly as soft as the day they were made, not turned into bubble gum. the rubber is still plenty hard enough to do the job it was designed to do. in fact, this experiment is nothing short of amazing. I started with rock hard intake boots (no longer made, and no replacements).the boots I installed went back to being like new functionally and 2 years later, are still working with no cracks. I also did second "control" boot and it is still soft in the treated area. I dipped just the last inch of the test boot & left it over night. the dipped part is soft enough to squeeze in, but still firm, the untreated part is still hard as a rock. the test boots were not used because they had cracks. this treatment will not fix a crack, but should help prevent cracks. rubber cracks when it loses it's plastisizers, one of which is the active ingredient in the wintergreen oil
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  19. k-moe

    k-moe Long timer

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    ^exactly^
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  20. kantuckid

    kantuckid Long timer

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    I say that real rubber, once hard and old, will stay hard & old, no matter what crap/goop you come up with! I've used pure glycerin on old door seals,etc., to liven them up but I'll not go so far as to claim it renews them completely. The cleaner prep for a tube repair is a rubber solvent that stops short of being harmful to rubber and will give it a new look. Try that for a solvent that's actually intended for rubber application. I use it on vintage MC parts for appearance purposes.
    Synthetic rubber will resist hardening better me thinks but I also doubt that once it's hard and old that you will really bring it back- as in all the way like a seal.
    The heat suggestion is gonna make it worse, not better! No on that one!
    #20