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(Large) Improvised/expedient Cement Mixer design/ideas ???

John Abacene

Joined: Oct 07, 2010
Posts: 114

I am well aware of the "Tow mixers" out there (usually having to make one yourself), but these are generally restricted to 'Papercrete' or similar things.
I like papercrete where it is best, and I love shotcrete. However, if I place too much priority on either of these methods, then I am ignoring a great resource, and that is all that gravel and rock that the ground can provide. A papercrete Tow Mixer, or anything using a blade cannot reliably make use of a mix incorporating any real proportion of gravel and rock without risking problems and break-down.

I need to do my construction out in the middle of nowhere, thus, electricity is either not an option, or not a realistic option, all things considered.
So I need to mix up a concrete aggregate using as much (small) rock as possible, and make as much mix at one time as possible.
A regular or gas-powered cement mixer will not really work for this. I would have to run maybe three of them, simultaneously, for various stages of mix to make use of them, and that gets either expensive or over-involved quickly.

This generally means having to use some kind of rotating or rolling drum or tub, and even a 55 Gallon barrel does not make as much at one time as I need to have ready or use.
- It comes close, I can make a pretty big build block with up to 45-50 gallons of concrete, but its not enough to pour even a small one-piece foundation.
Running one batch after another to fill a foundation gets risky as to 'setting' and the resulting quality of the foundation.
Thus, it comes back to having to use more than one drum mixer at one time, to have one mixing while I am puring another and filling another with the materials to start, etc.

I have tried envisioning some really big drum or tub that is heavy-duty enough to essentially be towed/rolled behind a vehicle, or moved around, rolling. in a circle, but again, it gets problematic and expensive real quick.

It is down to the point where I am seriously considering setting up the forms for a foundation, with notches or places for the rebar, etc., mixing the dry ingredients in the form, then adding the water, etc. and mixing everything right there in the form. I'm sure this idea might be frowned upon, but it is the only truly workable solution I have found.
If I do everything "The right way", then it becomes incredibly expensive, and likely impossible for someone who does not have several thousand dollars to throw at just pouring a lousy foundation, and yes, just having a truck come out to pour it is not an option for reasons I will not go into.
This, for several reasons, is necessarily a One-Man, Poor-Man's project.

I know it is possible. I will sooner or later figure everything out my own way, but I am also looking for any idea that can help make it happen as it needs to happen.

Thank you.

John Abacene

Joined: Oct 07, 2010
Posts: 114
What? - Nothing? - no comments, replies, etc.?
It looks like nobody has even viewed this....
C'mon... there has got to be some ideas or something out there......
Thank you in advance.
Peter DeJay

Joined: Aug 10, 2011
Posts: 104
Location: Southern Oregon
While I sympathize with your predicament, it sounds like a solution is evading most of us that fits your parameters (cheap, electric-free, able to do on your own, enough material for a pour, incorporating local material) Obviously the easiest would be to have a concrete mixing truck deliver the redi mix to you, but that might be cost/security prohibitive. To rent a mixing truck and drive it yourself would be expensive unless you know someone with one. To have several small mixers going with a small crew to be able to produce continuous batches so as to avoid setting and cold joints (this would be how i would probably do it) sounds like it might be too complex/expensive/unsecured for your situation. So it sounds like you need to fabricate basically a concrete mixer from scratch, able to operate off of a separate engine, or off the PTO of your 4x4 truck. If you don't have the materials, tools, knowledge or finances to do this, no amount of outside ideas or instruction will make it work for you. You need some type of cylinder, either an old metal tank, or maybe some coruggated galvanized metal culvert, and this needs to have a spindle so it can freely rotate. Next it needs some mixing fins welded to the inside, and finally it needs a way of getting out, so either a tipable platform or some type of auger or archimedes' screw. After this contraption is fabricated, it needs to be hooked up to the power source, and geared appropriately. Of course if its going to hold any amount usable for a foundation (5 yards at least) it needs to be on an extremely heavy duty trailer, especially if its going to be tipping. I imagine by this point we are beyond your parameters..?
John Abacene

Joined: Oct 07, 2010
Posts: 114
You make it sound impossible, when it is only difficult in concept.
I have already found the one, very simple solution, which is to prepare the spot, build a form, put the ingredients in place, and mix in place.
This potential solution, although needing refinement, and being fairly labor intensive, is again, very simple and extremely low cost. The trick would be in just doing it right the first time.
The idea of the type of improvised mixer you mention has been in my thoughts as functionally simple, but with the drawback of being fairly involved in construction, likely expensive, and more than anything else, the main drawback would be that it would be a major fabrication that may only be used once or less than a handful of times. - yet, is still on the back burner for its potential.
I do like the suggestion of renting a cement truck. I think this would not be available, but if possible would likely be a viable option.
I could rent say, three portable, gas-powered mixers, which also is still a viable option, and would keep me very busy during the given day and exhaust me, but essentially would work, depending upon the timing of everything.

I am looking for that one very clever yet simple option that is illusive, yet incredibly simple once found - that is my hope.

I have been toying around with the idea of a lawnmower-driven mixer that would act as a blender, that could be put onto/into one 55 gallon drum, and then the next, using a modest spindle or other arrangement that would work for the normal RPM of a lawnmower engine without either over-taxing it, or trying to mix too aggressively.
I have also been thinking of a similar contraption that would fit onto a stock tank, looking much like a tow mixer without being driven by a differential.
In either case, it would rest on the rim of the drum or tank with wheels, and the spindle also designed to again act as a blender or bread kneed'er, but instead of turning a bowl, it would move itself around the tank, etc.

I have also considered putting two such stock tanks together, coming up with something to essentially act as tire tread around its circumference, and somehow pulled/pushed/towed/etc with a vehicle.

So far, as crude as it seems, the mix-in-place option remains the simplest, least expensive, least contraption-like, and least wasteful of time and resource.
Being that I do not intend to pour many foundations, and possibly only one, it again makes all too much sense unless there is some better middle-ground between all possibilities.
If I choose this method, I would essentially figure everything to make the best possible, highest grade mix possible, to compensate for any slight inconsistencies or imperfections of the process.

I am also just beginning to wonder about making a specialized circular form, possibly with a first layer of crude cement, just to provide a useful bottom surface (for a likely, but not necessarily circular structure) first cementing a central post/socket/swivel, and fabricating some simple, manual gadget that I could push around in a circle from the outer perimeter, that would do the mixing.
Possibly as simple as a long pipe with a wheel on the outer rim of the form, with another slightly larger pipe slipped over the first which would have crude paddles, that might look like the blades of a push-mower, engineered to go through the mix easily, yet mixing it a little at the same time. This contraption could also incorporate a 55 gallon barrel at the center full of water that could be gradually released via a valve at the end to add water as needed, depending on the particular method and type of mix, to ease the blades/paddles along and keep the mix just fluid enough to work it, walk around in circles enough to make a thorough mix.
This central pivot/socket/pole/etc. could then possibly also be part of a simple gadget or gantry to help with placing the blocks forming the wall, or even to mix that in place as well, and otherwise aid in the construction of the building in general, as well as other potential uses.

I just came up with this last idea/paragraph as I was typing it and the paragraph before it - coming up with new options and ideas is not so hard if one remains open to possibilities, no matter how absurd sounding to begin with, tailored by the logical necessities and further options. I prefer to always be open to what others may come up with in any case.
I find that often in my design of some things, that letting the project dictate its own logic, and allowing the project to partially develop itself can result in wonderful designs better than if I limited myself, and forced the project into only the most conventional, already existent, or popular ways of doing things.
I think I may now have found my answer, in need of yet further refining, but I still would like to see any ideas from out in left field by anyone who can think out of the box.
- Anyone? - Anyone?...

Peter DeJay

Joined: Aug 10, 2011
Posts: 104
Location: Southern Oregon
To me, the problem with the mixing-in-place idea is the lack of quality control of making sure it is fully incorporated yet minimally watered. Concrete is strongest with minimal water, and to me, the idea of trying to mix 5 or 10 yards of dry concrete in a form seems unworkable. THe multiple small gas powered mixers would really only work if you had some help, as trying to fill, maintain, pour out, transport, screed, etc etc all at the same time would basically be the same as having one mixer going, as you would have a hard time doing it continuously without it setting.

The lawnmower design or similar simply will not work, even with normally aggregated concrete. I've seen a machine similar to what you describe for mixing clay slip, which is like smoothie-consistancy cob. It was a vertical tub, about 5 feet high and about 2.5 feet in radius, with an electric motor and propeller similar to a boats. But it wouldn't be able to mix rocks or anything even close to concrete. That's why concrete mixers, as opposed to mortar mixers, use a rotating drum, as opposed to a stationary drum with rotating impeller. A proper mix will just be too thick.

Part of the problem is all this focus on this one aspect of the building. There are sooooo many phases and elements to actually completeing a house, that to focus so much time and energy on one aspect seems to me to be more then its worth.

Ok, one last idea: Take a big drum, like big, like an old water taker truck, not semi size, weld in some fins inside it, lug it to your site, fill it up with the mix, and use your truck to just pull it around, rolling it one way, then the other.
d tei

Joined: Feb 28, 2012
Posts: 7
More info would be helpful.

What type of building are you wanting to build ? (stone, brick, cobb, stick built lumber, log, post and beam, strawbale, etc. etc.)

Basement, slab or crawl space ?


What region are you building in ?

Dale Hodgins

Joined: Jul 28, 2011
Posts: 5496
Location: Victoria British Columbia-Canada
The following is an excerpt from a long winded description of a cement mixer based on a $50 rototiller gleaned from page 2 of the thread entitled --- Mechanized green building techniques ---- where I describe a big mortar box set in the back of a pick-up truck. It can make about one ton af material at once. Designed to be fed with a front end loader. Material dumps out the back, perfect for pouring footings and stemwalls. Cost - Under $150 including the tiller --------------

The exerpt -- Another reason for the long mixer box is that it will fit my truck. A 10 ft. long x 32 inch wide box will extend just past the tailgate and there will be room to walk back and forth. This configuration allows the box to be filled by a front end loader. There would be 4 positions foreward and back from the wheel humps where pails of water or admixtures could be stored. ----------- Dry materials could be loaded up and then I could drive to point of use and mix the stuff. The mortar box needs a removable rear panel so material could be dumped into wheelbarrows or into the mouth of an auger mixer, a paddle mixer or a trommel depending on what is being made.

When emulsifying clay it works best if done over a long period. Starting the night before the slurry is needed, the clay could be broken up for 5 minutes and then allowed to sit a few hours before hitting it again. Length of time in the water helps the process so that total machine time need not be huge. I did some pottery and found this to be so. One batch of clay slurry will allow me to produce about 3 tons of finished cob. A reasonable quantity for an ambitious crew to use in a day.

This mixer would also be able to produce concrete in one ton batches. A simple plywood chute should allow me to pour most of my footings from the bed of the truck. My 32 inch wide footings will require about 180 lb. of concrete per foot, so each batch fills 11 ft. of form.

The tiller has room to extend the tynes by about 5 inches. I might have to change to a larger rear pulley to bring the speed down. Any extentions will be steel pipe designed to stir rather than to chop.

The photo below is my machine that was purchased 2 hours ago. Not bad for $50. Rototilling has fallen out of favor with those who care about soil structure. Plenty available.

Dale's picks - These are some of my favorite threads. Greed - My garden - ethics - Good wood bad wood Alder - Bees - Pulling nails -
John Abacene

Joined: Oct 07, 2010
Posts: 114

To: d tei

I am pretty much focused on some form of concrete, with the emphasis on using native material (sand, gravel, etc.) as much as possible.
I like shotcrete a lot, but prefer to be able to use as much coarse matter as possible (gravel, small rocks, etc.) I am also focusing on a heavy, thick wall made of large blocks poured in place.
So far, the size and design of such blocks is based on the max. practical amount of concrete I can make in a partially filled 55 gallon drum.
I plan on using a more or less modular method, to be able to re-use the same couple of forms. I may have to plan on both circular and square structure shapes, as there are certain advantages to both.
Building a circular foundation and building is much easier with the method I came up with in my last post, and is ideally suited for anything underground, for water reservoirs, etc. whereas certain applications and interior furnishings favor square-ish building.

I am looking at rural Klamath County in Oregon. I have also considered Arizona, west of Vegas, North of Lake Havasu, but not much chance of being able to put in a shallow well there for sure.
I have also considered Texas. IN neither AZ or TX would I want to be anywhere near the Mexican border though, regardless of any possible advantages whatsoever.
I was looking at a particular county in N. Calif. due to a very flexible building code I think they describe as "F", which means you build, then they come out to inspect, and as long as it is obviously pretty safe, you get approval, but in that area not much cheap land, and what there is is usually very small lots on the sides of steep hills. But the biggest problem there is that I hate California, its laws and regulations with a passion, as I grew up there and have spent the rest of my life anywhere but there.
d tei

Joined: Feb 28, 2012
Posts: 7
Using concrete in a remote location, in the amounts you're requiring, is going to be tough.

Have you considered using the Rammed Earth option of building ?

Advantages; cheap, can use on site materials (if present), straight or curved forms, can start or stop construction as needed, easy to repair or modify and has high thermal mass.

Here's my two cents regarding building and working with concrete. (I've done a fair amount of it)

Concrete (portland cement) is expensive, not to mention loading a mixer, placing and finishing it, is hard work. Once the chemical reaction begins, it waits for
no one.


John Abacene

Joined: Oct 07, 2010
Posts: 114
Cement/concrete - I am well acquainted with such. Used to do a lot of Stone Masonry too. I like the stuff!
This is, by its very nature going to be a labor intensive venture - at least as far as the foundation(s) would be concerned.

Rammed Earth: I have checked it out, don't believe in it nearly as much as concrete. It also takes a whole lot of work, it requires forms that are even more involved than poured concrete if you do it right, and other reasons. What I have also been considering is some compromise between rammed earth, 'soilcrete' and concrete. - they all have certain similarities.
For me, the big thing between rammed earth and some improvised form of concrete is the amount of moisture, and do you want to ram it or mix it? Why not a crude form of concrete - "soilcrete" that is vibrated into place, which is one notch below ramming it - but if I made a form that could be very roughly vibrated by using some old moped or small motorcycle-based contraption, then I could have the best of all worlds maybe? In fact, through previous experience in many things, vibrating it has definite advantages if I don't want any air in the mix. It would help bond the new to the previous layer/block/etc., would maximize density, eliminate air pockets and bubbles, (could be good or bad) and any organic matter still in the mix might rise to the surface where it could be scraped off - I have seen very professional concrete with fairly large pieces of wood/twig bits in it. One possible drawback to a more moist/fluid mix might be inconsistencies or layering such as what happens in a centrifuge.
- Too bad you can't use a centrifuge block maker, lol....

John Abacene

Joined: Oct 07, 2010
Posts: 114

Dale Hodgins: I kinda like your idea too... I picture just using the bed of a pick-up with a modified tailgate - the rototiller is very interesting - I might be a little worried about it chewing up the bed, even if it was just the all steel truck bed, but otherwise, it does have the ring of simplicity and making use of simple, easy to find and possibly inexpensive components. I will be keeping this in mind...
I am a little confused about the clay you speak of - could you explain the use of clay as part of your mix/process??
dan murf

Joined: Feb 17, 2012
Posts: 50
Location: Michigan West Side
John Abacene wrote:What? - Nothing? - no comments, replies, etc.?
It looks like nobody has even viewed this....
C'mon... there has got to be some ideas or something out there......
Thank you in advance.

Ok Here my spiel, Human Power
Take 4 wheels off a old lawn mower, You will need a 5th wheel eventually
Make a tilt frame, or mount wheels on a 2 wheel dolly (set-up dolly on a 45 degree angle) 5th wheel will need to be installed on the bottom
weld mixing paddles on the inside of a 55 gl drum (or smaller if you perfer) remember 145lbs per square foot for footing cement.
Take the rubber tire off the rear tire of a 10 speed bike. Reinstall rim on bike. Preinstall belt (see notes below)
Make a bike stand that hold the rear rim of the ground
Get a large belt, like the steamers use, the old leather ones would work and figure 8 belt around rim and the barrel.

I actually made a barrel set-up like this, minus the bike. Used a gas engine to drive one of the tire to spin the drum.
We didn’t use it much because it spun too fast, kept flinging cement to the outside of the drum and not mixing.
I though then a manual slower speed would have worked better! but it was a fun easy project.

"to Tinker or not to tinker, that is the question!"
If you build it better than the one profiting from it, don’t tell them, they'll get pissed! "I challenge anyone to challenge me" ... Murf! "I am responsible for the comment in this comment section"
Richard Cobbs

Joined: May 18, 2012
Posts: 11
Location: Yalaguina, Nicaragua
I am thinking of designing a bicycle powered mortar mixer, and ran across this post. In your situation, I would look into using a small rototiller. You may have to remove the wheels and run the axles on your footing form boards. I know that you can mix a lot of concrete in place with a tiller, I looked at a 40 foot by 60 foot slab that a friend had done that way many years ago in Massachusetts. After ten years of outside exposure, it had only one small crack.
Good Luck,
Ken Peavey

Joined: Dec 21, 2009
Posts: 2523
Location: FL
Sorry, been busy these past few months.

There is a way to build a slab (or any form) with a small crew, limited equipment, limited power sources, and low water: shoot it.

Shotcrete, or gunnite, is a means of continuously applying a crete material to any combination of forms, overheads, and highwalls.
Here's a link to click on.
This is a gunnite machine. You'll need someone to bust bags or shovel material into the hopper (1), someone to handle the pot (2), someone on the nozzle (3), someone to help the nozzle guy (4), forklift operator (5).
5 people. More is better, as some of the work is brutal. Rotate them out for a break.
It's dusty. Have an ample supply of N95 particulate respirators available, plus protective wear or replacement clothing for every 4-6 hours of work.
Experience matters. The right guy on the nozzle will get the job done better while using half the material.

You will need:
-an air compressor, industrial size, 180 PSI capacity
-a gunnite machine (the Pot), these can be rented
-spare boots (rubber gaskets) for the Pot
-gunnite hoses, should be available from the Pot rental guys
-water hoses, bull (air) hoses
-spare nozzle, from the rental guys
-spare water rings, from the rental guys
-lighting if you go all day and all night
-a pressurized water source, tanker/pump/generator will be needed for off grid work
-face shields
-the material in place ready to go
-a forklift to keep the material ready to go lined up
-the site formed and prepped
-action hoe, shovels, hand tools, wheelbarrels
-fuel for the compressor, forklift, and generator, if you go that route
-rubber boots sure do come in handy

How it works:
A guy dumps material into the pot, continuously
air from the compressor moves through the pot, blowing the material through the hose
at the exit end of the hose, water sprays into the nozzle
the dry mix is combined with the water in mid air to form the crete, shoots out the nozzle
the now moist mix, hits the target and sticks
a little bit of material will rebound
the nozzle guy keeps on moving and shooting until the form is filled

This method will install about 3 tons of material per hour, continuously-no batches. Cold joints are eliminated as long as the shooter knows what he's doing and flashes over the leading edges every few minutes. The amount of rebound/waste is reduced with an experienced shooter. Finish work is done with hand tools, scraping the surfaces to the desired texture. Mind you, this is rough work. You won't get a smooth surface such as a garage floor, but you can do the finish work with minimal labor and carpentry skills. You can use local materials if they are properly prepared beforehand. The largest aggregate would be in the 1/4" range, but the purchased shotcrete mix would be able to handle whatever stresses you desire. If you want strength, heat tolerance, or abrasion resistance, the material is out there. For best results, the environment and material needs to be above 50 degrees during application.

Seed the Mind, Harvest Ideas.
Richard Cobbs

Joined: May 18, 2012
Posts: 11
Location: Yalaguina, Nicaragua
Ya, I guess I've been away too long. Shotcrete here is the mason dipping his hand in the bucket and throwing stucco at the wall. At a building project that I have been following here, they laid most of the first course of blocks on one wall today. These blocks are solidified conglomerate and measure about 6x15x25 and weigh around 100 pounds (luckily I'm old and don't have to lift them). At one end of their wall they laid a full block (15") at the other they were down to about two inches. The phone service here (Claro) is laying fiber optic cable, several hundred miles of it! From what I have seen, it looks like one fifty man crew with shovels,picks, and bars, and one Sullaire compressor and jackhammer.
subject: (Large) Improvised/expedient Cement Mixer design/ideas ???