Has anyone built a 1+ yard concrete mixer?

[napabavarian]

I can't seem to find anything in my searches, so I'll ask, I was thinking of something on a trailer run off a small engine, 5-10hp, to keep the tractor open for other use, possibly with an auger in the bottom to agitate set up and built in such a way that it could be filled with the front loader, scoop agregate sand and cement into the FEL bucket, then lift and dump.

Any input?

 

[dfkrug]

Hey Napa:
There was a very interesting job site mixer I saw in Concrete Construction
magazine a year or 2 ago. It was (or could be) trailer mounted, made a
couple of cy at a time, and was easily loaded with a FEL. I highly recommend
you go to the World of Concrete show in Las Vegas in Jan or Feb, and you
will see one. Fantastic show, if you like bldg with concrete, like I do.

I use a PTO 1/3 cubic yd mixer, and I have fantasized about making an FEL-
mounted mixer that had a hyd motor and was reversible. Concrete weighs
as much as 2 tons/cy, so that is a major size limitation.

 

[RonMar]

Hey Napa:
There was a very interesting job site mixer I saw in Concrete Construction
magazine a year or 2 ago. It was (or could be) trailer mounted, made a
couple of cy at a time, and was easily loaded with a FEL. I highly recommend
you go to the World of Concrete show in Las Vegas in Jan or Feb, and you
will see one. Fantastic show, if you like bldg with concrete, like I do.

I use a PTO 1/3 cubic yd mixer, and I have fantasized about making an FEL-
mounted mixer that had a hyd motor and was reversible. Concrete weighs
as much as 2 tons/cy, so that is a major size limitation.

I have started designing one in Autocad for the FEL bucket as I wanted to start casting fence posts in place using a mould. Having the mixer in the FEL seemed like an easy way to dump concrete into a 5' tall mould at the far end of my property. With the price of motors and chains/sprokets, I started looking into using 2 DA hydraulic cylinders opposed by 90 degrees on a crank to rotate the paddles/auger in the hopper. I need high torque, not particularly high RPM for a mixer, and this might work better with my 5GPM available flow on my tractor pump. The crank plate has cam lobes that would reverse the valves controlling the DA cylinders to maintain rotation. It should run in reverse as well as it does in forward.

 

[dfkrug]

Interesting idea, Ron.

Have you looked into buying new hi-torque, low flow hyd motors? It seems
your approach has a lot of needless mechanical complexity that would offset
any cost savings of using cyls instead of one motor. But I did not say not
to do it!

I definitely agree low rotational speed is very important, and lends itself
well to torque multiplication. My PTO mixer is a little fast at the lowest
possible speed.

 

[DRL]

Interesting thread. Will follow closely as I want to build one of these someday.
Concrete Mixer 3 Cubic Yard Plans

DRL

 

[RonMar]

Interesting idea, Ron.

Have you looked into buying new hi-torque, low flow hyd motors? It seems
your approach has a lot of needless mechanical complexity that would offset
any cost savings of using cyls instead of one motor. But I did not say not
to do it!

I definitely agree low rotational speed is very important, and lends itself
well to torque multiplication. My PTO mixer is a little fast at the lowest
possible speed.

Yes, I looked at some and got sticker shock Most I found that could deal with the 5GPM though, did not output all that much torque at full pressure, so I would need even a larger reduction ratio to make up for it(overall lower mixer RPM with the motor running at full tilt. The 90 degree "V" twin may be a little mechanically complex, and quite a few hoses(2 cylinders, 2 spools and 8 hoses), but not particularly expensive. It was also pretty easy to calculate available torque based on cylinder choice and moment arm of the crank plate.

I went on to more pressing matters when I realized I had a real big unknown. I don't really know how much startup and sustained torque I need. I need to build the mixer hopper and auger and fill it with wet sand and see exactly how much torque is required to start and mix/roll a full batch. This would be very necessary if choosing a motor and gearing. At least with the cylinders, I could vary the setup and had a little more wiggle rom to account for errors. Once I build the hopper, I can then add a cylinder and using my third loader valve experiment with cylinder size and crank arm length. If setup right, a single cylinder might give 150-160 degrees of movement reliably. An auger/paddle going back and forth that far around the bottom of the hopper might even mix pretty well. Kind of like a hydraulically powered hoe in a wheelbarrow...

I was also wondering how the two timing spool valves needed for the "V" twin would hold up to being cycled once per second at 60 RPM... Quite a few unknowns.

 

[napabavarian]

Interesting thread. Will follow closely as I want to build one of these someday.
Concrete Mixer 3 Cubic Yard Plans

DRL

A great start $150 is a bit pricy! I might do it anyway

Hmmm, figure 5-6k in material since they say 3.5-4 but I bet I could start my own buisness with that!

 

[DRL]

A great start $150 is a bit pricy! I might do it anyway

I wish you would, and do a good thread here on the build so I can learn the do's and don'ts before I build it.

DRL

 

[mjncad]

Napa:

Take a look at United Rental as they have a 1-yard tow behind mixer available at some of their locations. It requires a 3/4-ton or heavier pickup to tow fully loaded. It may give you some ideas should you build your own.

I thought about renting one of these gems for a small concrete job, and went with an outfit that mixes concrete on site from their truck with a similar setup to the plans at the link above. All the ingredients are kept in separate bins and tanks, so the 90-minute window to deliver and pour is not an issue. I'm glad I went this route instead of renting the tow behind as it saved a lot of aggravation and back breaking work.

 

[therebarely]

Ron,

Have you looked in to casting the fence posts flat with a ubolt on top for lifting? You could cast holes for gates as well. You are on to something with the idea of casting fence posts. Have you calculated the cost of making 5 x 5 posts? I am getting ready to build a shed and might try concrete instead of treated lumber.