Epoxy

Try this one:

EPOTEK

There are several that would easily fit your needs, and some that are sold at small qty tube level.

I saw something on Blue Whales the other day that mentioned they are the loudest creature. I looked it up and the figure is 188dB (like being next to a rocket) ...and there is great controversy about SONAR use because it is thought (due to weird behavior like healthy-appearing specimens beaching themselves) that it is so loud that it damages the hearing of whales.

I believe that (Shore) is a measure of resistance to indentation. In other words, pressure. You might need something else, depending on which direction the vibration is acting with respect to the surface. A pressure wave will result in both pressure and tensile stresses on the adhesive. A shear wave will result in (duh) shear stresses.

In addition, you need to define what you mean by 'transmit vibration'. I'm not a mechanical guy, but I'd be willing to bet that the problem of maximizing mechanical energy transmission is analogous to that of maximizing electromagnetic energy transmission. That is: It is optimal when the impedance (modulus of elasticity?) is closely matched and energy reflection is minimized.

The strength of the adhesive only becomes important if the amplitude of the vibration approaches the strength limit of the bond.

This appears to be the sort of problems that people designing sonar transducers have to deal with.

What exactly was it used for? For securing components in a high vibration environment, that might damp the vibrations that the OP wants to transmit.

Well, we used an epoxy (simple two part) to 'glue' mounts for vibration monitoring equipment. The accelerator was in a magnetic housing and we epoxied steel rings (not much more than washers really) to rotating equipment at key points of bearings etc...). The mounts/washers provided a nice flat, properly oriented surface for the vibration pickup so we could do 'sound cuts'.

Two fold, 1) we wanted to know how much noise our equipment was making (submarines live / die by sound levels transmitted into the water) and 2) we could predict some equipment maintenance like simple balance, pump-motor alignment, bearing problems.

Maybe that's what the OP is after. But as I said, we used a simple, two part epoxy with quite good results.

daestrom

Metal filled epoxies pass thermal as well as vibration quite well.

The selection of a suitable adhesive depends on how much energy one can afford to lose in a sub-optimally coupled system. In your case, the signal level of vibrating mechanical equipment is probably high enough that some attenuation is tolerable.

The other thing to consider is the mass of the sensor, the flexibility of the adhesive and the resulting natural frequency of the sensor assembly. A massive sensor and/or flexible coupling will result in a lower frequency and result in attenuation of signals above that point.

The "flexible coupling" provided by the epoxies I've tried is causing issues.

It's been suggested that I try silver-filled epoxy and potting compound. Dental cement was also a suggestion. I'm looking at all of these.

FBt

The silver filled is used to attach IC chip dies to their heat sinks inside the chip package.

It is quite firm... brittle even, and is also conductive.

Requires 4 hr 80 C cure, however.

There are cooler, longer schedules.

hand held hair dryers work fine

let epxy cure to near solid, then heat

else it will reliquify and run with gravity, messy!!

my work once required magnets to be epoxied to core pieces in meter movements, they went thru ovens after primary cure for abt 15 minutes at 200 deg F

that was before engneering started using cryanoacrylite type adhesives, they seemed much better and harder with less work time, never had a release either.

preparation is key to good results

cryo is avail in gel or near gooy form

Loctite corporation has tons of alternatives available

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Wrong. There are plenty of epoxies that stay right where they are put.

Not only that, but capillary attraction will hold most in place.

Also, the extremely high temp a hair dryer or heat gun puts out is too much. It needs to be in an oven at a known temperature to cure correctly.

How does CA (cyanoacrylate) stack up against epoxy?

CA has high "pulling" strength, but is easily cracked by lateral forces.

Poor thermal, poor vibration. Not epoxy.

Try: Kearfott Guidance & Navigation Corporation

Can you quantify thos issues?

Perhaps. I suppose you could keep trying stuff until the system appears to work better.

I like Araldite 10, fast cure, 10 minutes to set, 1hr cure. The last time I ordered it it came as Huntsman 10. You should be able to find a spec. sheet online. Huntsman Advanced Materials Americas Inc. 4917 Dawn Ave. East Lansing Mi. 48823-5691

On Mar 22, 9:49=A0pm, Esther & Fester Bestertester wrote: > > The other thing to consider is the mass of the sensor, the flexibility > > of the adhesive and the resulting natural frequency of the sensor > > assembly. A massive sensor and/or flexible coupling will result in a > > lower frequency and result in attenuation of signals above that point. >

Devcon Plastic Welder or Stabilit Express are methacrylates that are much harder and stronger than the hardware store epoxies and cheap enough to try.

GG

There are some epoxies that give different characteristics with a different mix ratio, but not many, and NONE of those that do not should be manipulated in such a way.

The "stycast" I mentioned has about four different hardening schedules, and uses about three different hardening medias. All yield differing results for heat resistance, high temp softening after cure, etc.

When it is several grams of base media, and a few drops of "hardener", I call it barely qualified to be called epoxy.

When the mix is closer to 50 50, one will find it is more stringently adhered to as both constituents are critical to the finished medium.

Some mixes have to be accurate to within 0.1 grams or 0.1%.