Material for weighing down equipment

[David Winer]

So, you guys find that any weight, regardless of composition, density, or whether or not it is solid, does the trick? I mean, I know that weight is weight as far as weighing down, but what about vibration transfer and dampening?

This is the crux of your inquiry. Damping of sound and vibration is a technical subject that does not lend itself to one size fits all solutions. A lot depends on frequency (wavelength) of the vibrations and the material's ability to transmit or absorb vibratory energy. My GUESS in the case of your situation is that solid mass would be preferable to anything that moves (e.g., liquid or sand).

[Mike Cruz]

I'll file this one under "pixie dust"...both are as easily obtained...

[Mike Cruz]

Thanks, Jeff. This seems to answer my question directly. Sand is a dampener. While water, too, would probably work, the thought of a spill (yet another one) in my shop makes me hesitate.

[Mike Cruz]

I don't think the bearings are bad. It is a benchtop Grizzly drum/flap sander...enough said.

[Mike Cruz]

David, thanks. Sounds like this is where I'm heading.

Jim, that kind of info is priceless. Thanks. I'm adding this weight mainly for dampening reasons. Also, I like things to be substantial and solid feeling. Sand seems like the perfect solution.

[Mike Cruz]

Heeeeey, cheap shot! The bearings in my shop are JUST fine. Now, there ARE some screws loose...

Dan, maybe I didn't create a good enough visual. I wouldn't be adding bags of anything. I would be filling the column with either sand or concrete. The base will be bolted down so it won't/can't travel.

[Steve Ryan]

Decide on a shape and make the whole stand out of concrete. Not too hard to make a cheap ply form and mounting bolts can be cast in place. Don't forget the fasteners for castors, and a few re bars for strength. I have used female threaded anchors bolted into the forms. The type that is usually epoxied into a drilled hole in concrete. I have done a lot with epoxy concrete too, a mixture of epoxy and ground quartz chunks. Quartz chunks are slightly less than pea size. Not cheap but it makes an incredably strong machine base. Strong and stable enough that many metal working machines are made from a similar product.

[David Hostetler]

The only machine I have that has a vibration issue is my lathe, and that is because it is a midi lathe on a fairly thin stand. I lay a couple of bags of concrete on the plywood I mounted across the spreaders... If I need more weight, I put my foot on it...

[Thomas Hotchkin]

Mike, I use lead shot in small areas or sand in larger. Used truck tire inter-tubes with hose clamps on each end (tube are free at tire centers), seems to tame the vibration better. Tom

[Mike Cruz]

Thanks for recognizing the specific question I am asking, David. Funny though, now I've had two people understand what I am asking, and two opposite answers. UGH. The one saving grace is that if I try sand and it seems unsettling, I could always empty it and fill it in with concrete!

[Ryan Mooney]

Felder and some other European saws and combo machines are filled with concrete in the chassis. Their sliding table saw/shaper/planer/joiner combo weighs about 1400 lbs, I believe.

Certainly not an expert here, but I was listening to some (experts that is) on the FOG the other day and word is that that isn't usually "concrete" in the redi-mix sense. More like a compressed aggregate with epoxy binder (akin to the quartz countertops). I've talked to/seen some machinists who are using epoxy + granite for infill and weight in heavy milling machines/lathes. In my opinion thats overkill for most ww machines, and isn't really what you call removable (although I suppose you could fit cast removable pieces it would remove some of the point because the bonded join actually helps dampen vibration as well).

The fluid fill idea is interesting, although I share others concerns about leaks.. I'll have to think about that more. I'm thinking some sort of dilatant ( http://en.wikipedia.org/wiki/Dilatant - not dilettante which is a whole nother ball game) would work really well in some cases.. like under a lathe. The silica and poly mix might be just what the doctor ordered, although I do know someone who has done the bulk silly putty order (http://bulkputty.org/ordering/dow.html) - the price is a little.. off putting... You could combine those ideas though... cast infill pieces and then seat them in silly putty to pass the vibration through.

[Jim Neeley]

Mike,

I just edit that post to add iron to the list. If you've got some junk iron and pack sand around it, it's waaaaay denser than even concrete. Hmm... time to watch CL for some junk barbell weights? You'd have your exercise equipment always in the shop that way!! <g>

[Larry Rasmussen]

Hi Mike,
A variation of this discussion goes on in audio enthusiast discussion groups regarding how to dampen loudspeaker stands. The stands made for smaller speakers are not dissimilar to pedistal tool bases. The most popular vibration dampener appears to be sand. There was a pretty strong lobby for lead shot (used for reloading shotgun shells) for a time. However given the higher cost and some alleged ringing when the shot the concensus appears to be for sand. I've used both and have not noticed a difference. I have not noted any arguments for solid material like cement, although I have seen arguments stating cement would be prone to vibration as well and be worse than nothing at all. Given my experience with sand filling I believe it would be great for a tool base.
Good luck,
Larry R
Seattle

[Rich Engelhardt]

I have a few fat lazy relatives I should lease out..
All they do is sit around all day.
Trust me - they don't vibrate at all. That implies movement, which in turn implies effort...
I better stop @ that point. I'm enjoying the idea of cramming a couple of them under a machine waaaaay too much.

+1 on the cement bags.
Unlike the above - which just grows rounder - cement turns soild after a few months of sitting around.

[Mike Cruz]

Don't know why I didn't think of "fat lazy relatives" in the poll. Sorry...I'll be more thorough next time.