Most of the rubber components installed for isolation purposes such as
powertrain mounts and body mounts but are a natural rubber compound (good
mechanical, temperature performance and low damping for good isolation).
It is comprised mostly of material harvested at plantations of rubber trees
located in good geographic growing areas like Malaysia. It is then
compounded depending on application, with various small powders and carbon
blacks and typically sulfer or peroxide is uased as a cure agent. Then it is
cured and mold bonded to the metal brackets (molded at higher temps for
specific times). The OEM parts go through extensive testing in climatic
chambers (temp cycles, ozone, durability, fatigue corrosion/bond failure
etc.) and are tweaked to pass specific verification tests as decribed in the
DVP&R (design verification plan and report). Sometimes they are a synthetic
such as EPDM but typically you give up one or more of the basic desireable
properties that Nat_Rubber has. They do age and crack fail and there is no
way to stop that process, but it can be slowed down with quality materials
and processing. When you buy an aftermarket replacement from China for $10
you should probably buy a dozen if you plan on keeping the car. Though they
do have a shelf life so a high quality part that has been sitting for
several years is not going to perform as a new part.
My LHS mount kept failing on my 400+ hp XXXX Replica (been scolded for using
non-Imperial vehicular designations on this site and I don't wanna get my
mouth washed out with soap for a second offense) car so I wrapped a length
of cable around it and welded it together with my trusty Henrob (do not get
the mount of the surface that it is molded to hotter than ~275-300 degrees
and so far it seems to work fine (cars in winter storage but it did make it
there with no problem eh)..
>From: DONALDDICKINSOND@xxxxxx
>Reply-To: mailing-list@xxxxxxxxxxxxxxxx
>To: mailing-list@xxxxxxxxxxxxxxxx
>Subject: Re: IML: bonding rubber -- age issues
>Date: Fri, 2 Apr 2004 09:12:59 EST
>
>I am under the impression that rubber (which in most cases is really a
>synthetic compound) is due to the loss of plasticizers causing brittleness.
> This
>can be slowed considerably by treating, on a regular basis, with
>vinyl/rubber
>conditioners to replace these plasticizers (same for vinyl covered dashes
>etc).
>You chemists on the list what say you?
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