Vibration Damping Compound 1

[ADAG]

Hello, I am looking for a vibration damping compound to be used to fill a 1" gap between a concrete dynamometer base and the surrounding floor slab. Any ideas on a product for this application?

Thank you,

 

[GregLocock]

What do you want it to do?



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[NickE]

Sorbothane?

 

[ADAG]

I need to fill the 1" gap to isolate vibrations, reduce noise and protect the floor slab. This is an old installation, there used to some sort of elastomeric material in this gap, it has however dissapeared with the years and the gap is now full of dirt and debris. The contact material would be concrete on both sides. I guess there should be some sort of silicone-like product that may be inyected in the gap. The material must be oil resistant.

 

[NickE]

Tar?

Nick
I love materials science!

 

[ScottyUK]

what about the joint compound used for expansion joints on large structures like bridges?

For example

http://www.northamerica.stirlinglloyd.com/northamerica/products/joints/msl_mastics/msl_mastics.htm

Google turns up a lot of hits.


----------------------------------

Sometimes I wake up Grumpy.
Other times I just let her sleep!

 

[engjeff]

I second the tar, cheap and available.

 

[Heckler]

This could be costly but it depends on your level of protection

http://www.earsc.com/

Heckler
Sr. Mechanical Engineer
SWx 2007 SP 4.0 & Pro/E 2001
o
_`\(,_
(_)/ (_)

"Avoid the base hypocrisy of condemning in one man what you pass over in silence when committed by another." -- Theodore Roosevelt

 

[unclesyd]

A castable urethane would be the ticket. There is a little problem though with the environment, the gas and oil. Urethane doesn't like either one. I would contact the Devcon technical staff and get their opinion and any possible workaround. There might be some coating or additive that would protect the Urethane.

We used the Devcon materials to isolate some large fan motors

http://www.devcon.com/devconcatsolution.cfm?catid=14

 

[MintJulep]

No physical material will provide better isolation (reduced vibration transmission) than a gap (ie, things not touching each other).

What do you really need to do?

 

[Zapster]

two part polysulfide rubber

 

[chief]

I know many large diesel engines use a compound called Chockfast ( i think the spelling is correct)for alignment and vibration damping. It will be resistant to oil and diesel , as it is generally located in the bilge area.

 

[hydtools]

I agree with MintJuep, clean out the gap and install a flexible joint cover to keep stuff out of the joint. There may be a reason the original joint material is gone; it shouldn't have been there.

Ted

 

[plasgears]

Urethane is like a spring.

Tar-like compounds or tapes are good damping media. The remaining problem is how you keep the slab from settling in time. Two grades of asphaltic material: one generally dispersed and the other harder like feet to arrest rapid settling.

 

[ADAG]

I think I will agree with MintJulep and hydtools that the best is to simply clean the gap and leave it empty. I would think tar is too rigid.

Thank you all for your suggestions.

 

[Tmoose]

What is the dyno base sitting on? Cork, soil, ????

 

[ADAG]

Soil, according to the drawings

 

[Tmoose]

http://www.dynemechsystems.com/gifs/foundation-isolation.jpg

About all that can be reliably gained with a separate foundation resting on soil is the separate foundation can be thicker and proper width and length. This can be very important.

"Isolating" without genuine isolation (flexible, not bottomed out) materials all round is real chancy. Heroically deep trenches cut around vibrating machinery sadly often provide no signicant reduction in transmitted vibration

 

[polleke]

Hello ADAG,

We use Chockfast Orange as a filler material.
You can get Chockfast in several different types
It's a product from: ITW Philadelphia Resins

Look at

http://www.chockfast.com

Choose your type

Harry