Myths: Solvents & O-ring Chains

by Mike Chaplin

Date: Mon Jul 11 23:57:09 1994
From: (Mike Chaplin)
Subject: Myths: Solvents & O-ring Chains ...
RK and the other o-ring chain manufacturers CLAIM that cleaning your o-ring chain with solvents or using a spray chain lube (which has a solvent in it) will damage the o-rings and shorten the life of the chain.  My friend, Earl Minkler (Valley Machine, Livermore, Ca.), and I decided to do a little testing.  We took some excess RK530SO chain links apart and removed the o-rings.  Each o-ring was placed in a separate small bottle.  We then added to each bottle one of the following "solvents";

1. MEK (Methyl Ethyl Ketone) a nasty solvent in the same family as acetone, but much stronger.

2. Chevron Thinner # 325 - a petroleum naphtha-base solvent

3. Freon - the solvent in most "contact cleaners"

4. unleaded gasoline

5. WD40

The bottles were then capped to prevent evaporation for a week.

We didn't test kerosene as it is the ONLY solvent each chain manufacturer actually recommends for cleaning.

After 24 hours, the only noticeable change was in the MEK; that o-ring had swelled slightly.

After 1 week ... The o-ring in the MEK was twice as large in every direction, the o-ring in the gasoline has swelled slightly, and the others had not changed.

We removed all of the o-rings and let them sit for 24 hours.  The MEK and gasoline o-rings had returned to normal size.  We checked the surface of the o-rings vs. an o-ring that did not see any solvent and there was no apparent change in the surface of any of them with 10x

We then stretched each o-ring over a 1/4" bolt to check their elasticity; again no difference in any of the test o-rings from the untreated o-ring.


1. Any of the solvents that we tested would be safe for cleaning an o-ring chain; if the cleaning time is normal, < 1 hour, and dried afterwards.

2. Solvents in a spray chain lube will evaporate long before it can effect the o-rings. Something else in the chain lube might damage the o-rings, but most solvents won't.

Additional Thoughts ...

If the o-rings were to swell as we noticed in the MEK then it is possible for the o-rings to wear more quickly against the chain's side plates.

I believe that the major failure modes of the o-rings are; (1) lack of lubrication for the o-rings, and (2) dirty o-rings grinding against the side plates.

There has also been some concern about a solvent getting past the o-ring & diluting the internal lube.  This shouldn't happen, unless the o-rings are already damaged; in which case, you will be losing the internal lube at an accelerated rate & shortening the chain life anyway.


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