Any common anti-thixotropic material?

No. Come back on topic. Cream is antithixotropic. I had forgotten that. So, I could perhaps make a dashpot with cream (except for the spoilage issue!). So, what acts like cream without spoilage? Omigod! As I'm typing this, the answer is obvious - personal lubricant. A GA for your dirty little mind!

Silly Putty. But I don't know how well it would work in a shock absorber.

This was mine. Forgot to log in.

TVP45,

The low-pass function is inherent in many of the A/D circuits used for load cells, especially sigma-delta converters. SAR converters can low-pass filter by averaging. Additional filtering can be added with very inexpensive components.

A mechanical low pass filter will be difficult to make very effective without affecting the accuracy of the load cell. Is your mechanical vibration destructive? If so, have you considered active vibration cancelling such as the Bose system?

LG_DAVE

Excuse me,

i'm some perplexed those anti-

Is it meant that viscosity should be constant for all operating conditions?

If so, maybe something like glycerin based products or automatic transmission's oil?

It was just mine 5 copecks.

I,m looking for a material where high, short-term stress has a low viscosity but lesser, long term has a higher viscosity. I've always heard that called anti-thixotropic (sort of the opposite of silly putty), but I'm no material scientists so that may not be the right terminology. Del jogged my memory when he mentioned cream (which does that) and I rmembered that personal lubricants do the same. So my thought at the moment is to make a dashpot with a mesh of holes and cool the whole thing to (maybe 5^oC?). Then I have to figure out how to submit that on an expense report!

I can appreciate that electronics do much, much better job, but I want a mechanical one.

I couldn't think of anything but the opposite of what you want. But at least this article gives you another search term, and mentions gypsum paste and printers inks.

When I stir peanut butter to make it more spreadable, I stir clockwise. So simply stirring anti-clockwise should make it thicken.

You're getting into some dangerous teritory with regards to accuracy if you want a "thick" liquid to do damping, as it will cause sticktion / hysteresis.

Perhaps you are looking for a material that has high viscosity when there is rapid movement, then low viscosity in slow movement? Sort of like corn flour (/corn starch) and water mixed into putty - while you knead it becomes almost solid, let it sit and it turns into puddle.

Try hydraulic damping... I used to install some load cells, I think they were from Rice Lakes, or Tedea-Huntleigh, they have a beam type cell installed within a damping system, you just have to install the "brick" and it is pre-dampened. Google "load cells damped 9010" and you'll find a stack.

Well, maybe. I'm often in dangerous territory but this time I don't care about stiction or hysteresis.

I really do want something similar to what I asked for. I can just get this to work using yellow memory foam (none of the other grades work worth a darn), but it responds to really high shear and I don't want it to.

Like I said, I know there are better ways to do this, but this is the way I want for now. I'm old and cranky and like to try new things in different ways. Besides, if it doesn't work, I can think of several practical jokes I can do with ice cold KY jelly.

Critcho has understated the use of corn flour as a non Newtonian liquid.

There are lots of clips on You Tube of people running on baths of the stuff, here's one:-

http://www.youtube.com/watch?v=IRlBuZsScho

A Silicone oil of sufficient viscosity is used in many similar applications. I frequently rebuild Tracer mill probes dampeners and it works well and is extremely stable and will not spoil.