I’ve found a use for that old scroll saw or reciprocating saw. Attach a small clamp to the chuck, glue a piece of sandpaper to the clamp pads so the paint bottle doesn’t slip out and there you go. an inexpensive paint shaker to go with your paint stirrer.
I just stir it up with the butt end of my paint brush.
Great idea, thanks for posting!
Mike
What are you? MacGuyver? ROFL!! I’d hate to think what’ll happen if the paint bottle had slipped out of the vice grips. 
And they say innovation is dead, HA!
Very nice, but I have simplified your concept somewhat. I use my hands to hold the bottle, and shake it by rapidly moving the hands up and down. [:)]
I am drawing up plans for a slow barbecue spit style paint rotator rather than a shaker. I will use one of those slow speed geared motors, very low power, a few rpms. I will make the rack sized so it holds the two bottle sizes most of my paint comes in, even when upside down. It will hold several bottles- the colors I need for the model I am building. With it turning through a full 360 I hope the paint will stay in a useable condition whenever I need a color.
I do the hand way most of the time as well, however, I find that a vigorous shaking and string (sometimes with the end of my paint brush as well), is needed for those older paints, that are say 15 years old because of an hiatus, and I don’t want to spend my retirement money buying new paint. Especially when a 2 oz bottle of MM enamel you have has a price sticker of $1.95 and the new ones are what? $3.50 - $4.00?
It comes in handy at times, and I thought it would be nice to share.
While I think it is usually better to stir paint instead of shaking, I have added several steel beebees to paint to cans of Humbrol or bottles of ModelMaster enamel in order to agitate the paint while shaking, much as the balls in a can of spray paint. Combining that idea with your mechanical shaker might work even better modelcrazy!
Gary
Don, get one of those foam noodles designed for kids at the beach. I attached one to an old Sit-n-Spin all around the outside of it. I am going to upgrade to using a bike wheel*, though. Anyway, you slit the foam all the way around from the side. It holds more than twenty bottles at once. After you turn it a few times, with beads in each bottle, the paint is mixed enough to allow that project’s paints to be just stirred before use for each color.
After many dire warnings on the internet about shaking, I feel compelled to add this. “Only use beads in your bottles and agitate or shake your paints before you stir them with a stick if they say ‘Shake well before use’ on each bottle”
the foam noodles are just the right size to cut off and make anti-tipover sleeves with also
We all know that “paint can’t possibly last” if you shake it,so, my 3 year old stock of Acrylics is now in danger of ‘spontaneously spoiling’ after three years of shaking, spinning and stirring.
*(If I had used an old bike, I could have cut it off and kept just part of the back half and the pedals, and had a speed reducing handle to spin the wheel with, because low speed is the key to making this work, the two beads have to move back and forth inside the bottle, if you spin too fast, they stay in place and just ride around with the paint, accomplishing nothing in a big hurry,something like the high gear from a ten speed, and turn the “handle” really slow would work)
I like the BBs in the bottle idea, that would really shake up that old paint of mine. Admittedly, some of old stuff is just too far gone, but the ones that are still “new” or still pretty full seem to rejuve just fine.
use Hematite beads,they can’t rust because they “already are”, they won’t break like glass ones could, they aren’t sharp like stainless hex nuts
I have found some old Testors paints, both the square bottles and the MM, after time and if they have been opened, harden to the point where they will not dissolve with thinner and be discarded. I have to pitch them. I can remember when the square bottles cost 10 cents! However, my income has pretty much kept up with inflation except in recent years, and I find even when I buy new paint for a new kit, the paint represents a minor cost compared to the kit itself and resin or PE aftermarket accessories.
I have always wanted to lay my hands on one of those watch cases designed for self winding watches. You plug 'em in and they will routinely move the watches so they stay wound while not in use (just set it and forget it).
Obviously not a vigorous shaking, but probably enough to keep the paint suspended and mixed. The only issue would be that you could only do a few bottles at a time…maybe the bottles being used for a current build. Seeing that our paint stashes can exceed 30 to 50 bottles sometimes, it would be a million-dollar idea to come up with a device to accomodate a high number of bottles.
I like the BBQ rotisserie idea. Nice and slow. I’d just need to figure out a way to keep the paint from leaking out once I skewered the bottle on the spit.
No, really…that might be an excellent starting point for a slow agitator. Between that and the foam “noodles”, I think there’s the beginnings of something here.
Matt
there is another variation of an old tip that also works
Take an old electric knife, and instead of dulling the blades and taping a pill bottle on one of them, make one into a mounting point for a removable pin.
mount the knife onto a board, anchored nice and solid. put another shorter board on channels on the long board. mount a pair of angle brackets onto that top board, pinning the dulled knife blade in between them
mount two of those cheap plastic flip lid compartmented boxes onto the top board. You would then load up your paint bottles in the boxes, close the lids and turn on the electric knife
A simple rheostat in the power line would cut the speed down to just a back and forth “shush, shush” as the beads move back and forth inside the bottles
If you have ever made the one that people link to online, you know that the force and speed is too high with the knife running at stock speed
just like if you get the wheel spinning too fast,the beads don’t move up and down inside the bottles, they stay in one end (that means that you know that there is no stirring going on, beads or not)
shaking by hand is perfectly fine, too,but, those of us with Arthritis may have aggravated that with all the paint shaking through the decades,and even it it didn’t contribute, it is no picnic after Arthur comes to live with you. I also have over 700 bottles of paint now,shaking with some sort of tool is sort of mandatory these days (even if I only mix what is going to be used on “today’s project”,that is in the area of 20-30 colors on each aircraft)
Rex
You guys are giving me ideas. A MaCGyver may be in the works again.
Or Rube Goldberg.
While I love Testors enamels, both square bottle stuff and MM, if they sit for a month or so, the solids settle out and become so gooey that hand shaking just doesn’t work. These paints require at least some stirring. Once you stir it, then shaking works until you let it sit again for a few months.
On the other hand, paints are still not so expensive, compared to kits, so I guess I could afford to buy new paint for each project, but it is hard to throw out paint of the right color 
Right , Don. I recently threw out a couple dozen bottles of very old paint, looked like they were beyond salvaging. Other than that, I just stir them up with a stick when I want to use one. Simplicity is my watch-word.
I think there is a big misunderstanding about shaking the paint.
I can’t speak for everyone that shakes their paint, but, stirring is still a part of the process. (just not a high speed tool that goes whirrrrrrrr, splattttererrrrrrrrrrrr, dang!!)
You take off the cap, break up the “goo” a bit with a stir stick or tool, replace the cap, and agitate with the beads in there until the paint is well mixed. (a shaker allows you to do it longer than if by hand)
Then you put that bottle down and do the next one. If you are doing a batch, you prep each as you load your shaker.
after they are all mixed for the current project, they sit and wait their turn,any bubbles settle out during this time
then you stir them a little bit as you open each one for use. (and you remove the lid and stir again as you go if you are using any color for a long time, or for multiple airbrush loads)
I read too many times that “shaking the paint causes bubbles”,those typists must believe that we are shaking the snot out of it, popping it open and dipping a brush directly into the paint all at once. The type of caps, the beads, the settling time,or even the use of a palette is simply never factored in,that is evidenced by the “what do you mean by prime the brush?” comments.
Rex
Great minds think alike. Here’s my rendition. I used velcro fasteners so the paint bottles stay in the shaker and not the ceiling or my eye [blkeye][;)] for that matter.
17 yr. old Pollys S paint
After a short run, completely mixed. Def. superior to a powered mixing tool or manual shaking in my opinion.
