Author Options:

Tool for vibrating concrete? (DIY?) Answered

So I've been thinking of making some homemade concrete stuff with different molds I plan on making.

Since I'm not a big expert on concrete and such I've been reading all over the Internet for how-to guides and what not.

And something that seems to be a really good idea is to use a tool to vibrate out the bubbles and air pockets from the molds before they set... and so far I've not found any instructable here on how to make such a tool ( because it's a bit expensive to buy one, and hey.. why not make it myself)

So my question is simply if any one know of a good idea of such a tool, how to make one or whatever..

(maybe modifying something, making one from an electric motor?) I need ideas!  


There is an obvious way, Get an old (MAINS) hammer drill (Bearings are better on a hammer drill) and put a 6^ to 8" 12mm bolt in thread end first. The bolt needs a slight bend in it from about half way up the shaft so that the part of shaft in the drill is straight. The bigger the hex head the better, you could even put a large washer locked off with another ny-lock nut. The vibration can be tweaked by making the bend more or less (Should only need a couple of degrees.. The variable speed will enable you to vary the frequency of the vibration. The whole drill needs to be fixed solidly to a metal plate or a solid piece of plywood. this can then be temp bolted to either end of the workbench when pouring the cement... This is what I will be building....

If you want to use a drill like this then you must be quite desperate.
Sounds like a quick way to wreck the drill too...
Just make a crank shaft that pulls on a plate and with a motor that is mounted on another plate - thick playwood should do.
Place the tube from some old car tyre between the plates and let the motor run.
You don't need a long crank, a cm or two is more than enough, like from some old lawnmover engine.
The pressure in the tube gives the support for the weight of the concrete and you can adjust it to the load and usable movement of the crank shaft.
At least this way the drill will only work as a direct drive and stay without cracked bearings - if you have a solid mount for the bottom plate with the crank and motor mounted...

Yes I agree, a drill wouldnt last forever Hence I did say use an old hammer drill coz the bearings are stronger, you can pick up old mains hammer drills from the carboot for between 5 and 15 quid. The length of the shaft may need some experimentation. The point is it will make a useful vibrator with a variable speed which is needed and it is very very cheep.

I like this guy's table, it's just a old tire and a piece of plywood....


I would think if you pulled a motor out of a old washing machine it would be easy enough to create a vibrating motor, just foul up the shaft a bit and run it on high spin....

hey there, I work at Baldor electric and I'm pretty sure that we build vibration motors for concrete and they didn't have too high of a price on them; although the price for each model that is listed on our shop floor display, I am not sure if it is actual cost or customer price.

why waste money? just get a peice of 2x4 and tapper accross the top!

I am on the same quest my friend. I did see a guy on the net that took, what he refereed to as an inexpensive vibrating motor, and attached it to the center of a 24" x 24" square of 1/2" plywood that he had bolted to a tire. It worked amazingly well in the video. However, the motor he was using costs $220: http://www.historystones.com/accessories/vibrating...

I am looking for a more DIY diy solution. Like... using an old washing machine spin dry motor, or a harnessed power drill spinning a bilaterally asymetrically weighted washer solution.

That is what I plan to do. I am building a concrete coffee table that has a 20"W x 48"L x 2"Th. I plan to do the following.

1. Take my Ryobi power drill, which is not cordless and is pretty damn powerful
2. Drill a hole in one side of a large washer.
3. Use a metal file to file the threaded end of a bold into a hex'ish shape, keeping enough of the threads to use a nut to secure the washer to the bolt.
4. Use epoxy to glue a heavy nut to the opposite side of the washer, 180 degrees from the bolt
5. Lock the filed down hex-shape end of the bolt into the drill.

Now... Before I say another word... anyone reading this should be wincing, because I am basically describing how to make a very dangerous, and goofy looking weapon. I plan to never test it unless it is mounted to the plywood that is bolted solid to a car tire. That way, if/when the bolt slings off, it will smack the inside of the tire, and not my kitchen window, or my head.

Come to think of it... there has to be a better way. Anyone?

Those probe-like immersion vibrators might be too big for your tabletop. Just hold a vibrating hand/palm sheet sander to the form, not the ones that rotate or use a belt. Use it without sandpaper, of course. Those units are pretty inexpensive on the scale of buying tools. Good luck.

Best way to get air bubbles out is to vacuum the mould - A shop vac may be enough.

A palm sander works pretty well. You can pick one up at your local DIY store for about $20 or even less at a garage sale.

Get a Skilsaw, remove the blade, and place the saw against the form. Pull trigger.... Concrete vibrated.

I saw a video on the Fine Homebuilding site showing it being done, but I think its behind their paywall.


Would the generate enough vibration to get enough air out of the concrete?

Seems like a simple and straightforward thing to do, might give it a shot.

now thats really interesting and it solves the isue for smaller molds.

the question now is whether or not it works for larger ones

well duuuh... >_>

the reason why i can't specify it is because i have a lot of different stuff in mind, both small and larger molds... hence the vague explenation


Depending on the size of the pour, you might want to attach the small motor at the end of a few wrapped steel cables so you have a "probe" to stick into the cement. If not, I'm not sure about those commercial cement vibrators, it might just be a weight at the end that just picks up the vibration transmitted through the shaft with the motor held outside the mold. Good luck.

taking a look at these http://www.harborfreight.com/power-tools/concrete-vibrators.html it seems like your typical reciprocating saw that may drive a weight at the end of the flex shaft going back and forth in the endtube creating a hammering vibration.

yeah I've seen those on the net before, bit out of my pricerange though...

might need to pick up a cheap electric motor and work something out or so.

kinda out of ideas at this point :P

if you can find a print shop going out of business, they may have a bunch of "vibrators" used to align pages for envelope stuffing purposes.....they normally have a rather strong vibrating motor on them ...