Please help with cement mixer

[bchee]

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[Milton Shaw]

Simplest would be a dryer belt and idler pulley system that goes around the outside of the drum. How are you going to dump the cement out of the mixer or wash it out for that matter.

 

[bchee]

dele

 

[IndyGarage]

I bought one of those cheapo Bigcat plastic mixers about 10 years ago. A lot of people complain about them, but I've used it about 5 times with good luck and my father in law mixed up a bunch of tile grout and quickcrete in it. The weak link on it is the drive mechanism - google it for pictures.

I'd bolt a short shaft with pulley to the center back and drive it with a belt from a motor. The tricky part is that you have to be able to dump it out, and that drum seems like it wouldn't dump well.

 

[Sureshot]

I'm thinking about getting a long belt to go around the entire drum, but I'm not familiar with the math to calculate how fast the drum will spin, or how much strain it will put on the motor.
The drum just sits on the wheels, so to wash it out I can move the whole drum.
To get the concrete out I will just do it by hand, since I'm not pouring very much. And again I can just dump the whole drum over. I think I can mix two 80 lb bags at a time in it.

Driver circumference divided by driven circumference times the drive speed. You are going to need a further reducer.

I would only plan on one bag in that unit. It needs room to move to mix. You will be surprised at how heavy that will be to handle.

What size project are you doing?

 

[rkevins]

motor speed times motor pulley diameter divided by size of drum ( if you run belt around drum)
example: 1000 rpm motor x 2" pulley / 10" pulley = 200 rpm
I had a spredsheet setup when I was caculating pullies and speeds for our sawmill

 

[lilredex]

Here's one made from a juice barrel. It rotated on a 1" shaft in flange style bearings. Pulleys from old dryers formed the two stage drive system that worked OK for a while, until the second stage belt started falling off. That was all changed to a worm drive speed reducer and it performed flawlessly after that.

I poured a couple of retaining walls and a driveway, all in small sections.

Not a good picture but, the driveway is on the LHS and a wall is on the RHS.

 

[bchee]

dele

 

[bchee]

dele

 

[lilredex]

It was a 1/3 or 1/2HP from an old dryer.

This is the speed reducer, a 15:1 ratio. Half of the shop made coupling is shown.....the other half was a channel in which those pins ran loosely, but securely.

 

[Sureshot]

Thanks for the formulas guys.
This will be used only for small projects. The current project is a 2" thick countertop.
I won't be moving the full drum manually, I just plan to scoop out the mix by hand. In many of the countertop-making videos I've seen they just fill the mold by hand.
Anyway, I also plan to use it to mix mortar for tiling my floor.
Once the drum is empty, I can just pick up the whole thing and take it outside to wash it.

Regarding a 'reducer' I assume it will look something like in this new picture

That will work but a worm gear reducer is what you realy need to get it slow enough. Google search for a speed. If it goes too fast centrifigul force will just put the mixer out of balance or in your case kill the motor. You need the mix to keep rooling back on its self for lack of a better explanation. Off the top of my head I would guess 60 RPM is still on the quick side. I have a 3pt one on a 540 rpm PTO and I have to leave the tractor at idle to mix.

 

[bchee]

dele

 

[Duramax963]

Pretty cool.

 

[Sureshot]

For the amount you want to do you should put a hand crank on the front. Like the speed knobs for a tractor steering wheel or spring for the $100 unit. Seems like you have a lot of obstacles ahead and limited resources to conquer them.
I am all about free and repurposed but sometimes a guy is just spinning his wheels and is better off biting the bullet and paying for it.
Do you have a bike, car, tiller or something already semi "rigged" you could use as a drive?

 

[IndyGarage]

Ok the worm drive reducer makes sense but it will be at least least $100
I was trying to go as cheap as possible on this.
At that price I might as well get the HF mixer. That one spins at 36 rpm.
http://www.harborfreight.com/3-1-2-half-cubic-ft-cement-mixer-67536.html

edit: just saw a winch that I might be able to use somehow

That thing has soft gears and the worm will eat the gear in about 1 hour of use - Trust me on that... I tried to build a drill powered trailer mover out of one.

 

[racingtadpole]

Chain drive using some gears from a push bike. Cheap and easy to source, easy to attach, wont slip, multiple ratios available, can be geared in multiple stages to slow it right down.

Although for the price, I reckon I'd shell out for the Harbor Freight one

 

[454ragtop]

Have you looked around on CL or whatever, might find a used one that needs some work, probably easier to fix one than make one. I was given one with a junk motor and needing a couple other small repairs. Mine has a bigger drum than yours, and a 1/4 HP spins it fine by the time you gear it down to run slow enough.
HTH, Jim

 

[bchee]

char

 

[89GLH]

Sometimes you need to just bite the bullet and invest in a tool, rather than trying to hack one together. Especually since welding is off the table. You'll have better results if its all poured together, rather than scooped out and processed slowly. Last thing I would want is a counter that everyone coming into my house would see, looking like ****.