Scott Speirer wrote:

With regard to Perry Mick's tension bolt failure, I highly doubt that

coating the new

or original tension bolts during the rebuild is going to prevent a

recurrence of a

failure.  You might as well cover them with bovine scatal matter before

installation

- the amount of protection will be the same.

Mark Wrathall
RTV is probably easier to obtain in S.Cal, easier to work with and less
corrosive :).

I was also suprised by this suggestion, but when you think that the RTV is
not changing the resonant frequency by added weight, rather is damping the
bolt by submersing it in a thick fluid in an enclosed space, you can see how
this idea has merit. The fact that has been considered a remedy in the
racing scene adds at least circumstantial evidence that there is some value
in it. Although it is of unproven benefit, the pain/risk/cost involved in
doing makes it worth trying.

I am not sure about that. We got a lot of cows out in Covina :-) Cowvina?

When RTV sets up it is fairly high durometer. Not really a fluid.
How do you classify rubber? Not a solid.

Paul Lamar

The term is elastomer.   I would expect a substantial damping effect from
encapsulating the bolt in RTV.  One thing to worry about is totally filling the
cavity.  RTV has a VERY high CTE and in a fully trapped (and sealed)
application can generate EXTREMELY high, essentially unlimited forces
when heated.   I have seen a 2" thick 12" diameter flat steel lid attached to a
thick walled 12" steel tube with eight 1" studs deform enough to let the cured
RTV dribble out when heated to 350F.   Leave a bit of air space or it WILL
make room.

If the bolt problem is guitar string type of vibrations (lateral
vibrations), then
providing an elastomeric doughnut (sleeve, tube, whatever) in the middle
which is snug on the bolt and in the hole will dramatically detune the system
and provide substantial damping.  Both are good.

If the bolt hole size is consistent, I'd use a sleeve in the middle portion.
Sounds
like what the 20B has.  It needs to be a snug fit in the hole, does not need
to cover the whole bolt, does need to be in the middle, at least approximately.

Bill Freeman

 
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