Mixing concrete with a concrete mixer, 101

   / Mixing concrete with a concrete mixer, 101 #1  

wroughtn_harv

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Okeedon asked but I'm sure he's not the only one to wonder why I do so much mixing on site with a nine cubic foot mixer.

For me it's about control, quality, quanity, and time versus both of those.

It's also more economical. Buying Portland cement, sand, and gravel and mixing myself versus buying redimix usually works out to about a thirty to forty percent savings. That's if I'm doing four or more yards at one time.

If I'm mixing smaller quanities or taking time dispensing it from the truck the savings go through the roof. The ninety dollars an hour wait time really gets expensive rather quickly.

The biggest downside to mixing it on site in a mixer are usually two fold. One is it's hard work. The second is getting it right.

I use nine cubic foot mixers. They're easy to identify. If they don't say they're nine cubic footers you can fill it with mix. It will fill two six cubic foot contractor's wheelbarrows heaping if you've got your slump up-mix stiff. Three if you've got it wet and not able to heap.

One word of warning here. A heaping six cubic foot wheelbarrow takes just a bit more skill than strength to handle. And it takes a lot of strength, you're handling six hundred pounds or so.

There is some humor watching the unwary grab a hold of one of these beasts. It's a funny ha ha more than funny peculiar unless you're the one that has to clean up the mess.

Another way to check your mixer for capacity is to use a light weight aggregate mix like Maximizer. Their eighty pound bag of mix will make one cubic foot. A eighty pound bag of the cheap stuff like sacrete only makes six tenths of a cubic foot. It takes thirteen of the sacrete to fill a nine cubic foot mixer or just nine of the Maximizers.

On the pond project I'm using good washout versus just washout. The difference is good washout is put through a process removing most of the concrete so you end up with a sand and three quarter rock mix. With regular washout you end up with quite a bit of concrete dust and large clumps.

Washout isn't available everywhere around the country. In some areas it's already purchased for a special purpose. I've heard of one place that uses washout exclusively for septic tank fabrication.

I'm getting a heckuva deal on the washout. It's allowing me to have good concrete for less than forty dollars a yard. Compare that eighty to a hundred dollars a yard quantity users are now paying.

Mixing it myself allows me to mix it stiff when I want it stiff, and wet when I want it wet. Today I needed one mixer load for lamps in the bottom of the pond. Yesterday we mixed about four yards for three different components. We did this in three different times as required. If we'd had a truck come in we'd have faced being ready when the truck arrived and not having the time to control the pour without either paying a waiting fee ($1.50 per minute) or sacrificing the variety in the slumps we wanted.

It isn't for everyone. It's easy to screw up. But if you like having total control of your project and it's a series of steps then it's great.

In my prime (mid forties) I once mixed, poured, and finished nine yards on my birthday by myself. It's only hard, not impossible.

A week ago we mixed ten yards an poured it between eight thirty in the morning and noon. That's one fifty seven year old shuttling the material and helping the fifty eight year old feed the mixer. We had the young guy (forty nine) screeding by himself.

Thursday we'll do between twenty five and thirty yards. We'll have two mixers going with two guys feeding each mixer. There'll be two guys in the pond screeding and I'll be shuttling the material between the mixers and the pour.

It would be easier to use a pump truck and three truck loads. I'm sure we would find a way to set up without the pump truck tearing up the trees. And the cost would be about three thousand or so.

Running day laborers and friends we'll be able to keep the cost down to less than two.

And probably just as important, the friends will have a story to tell. /forums/images/graemlins/grin.gif

A couple of other points to consider while were considering.

Concrete gets a lot of it's strength from the rock used. I prefer granite three quarter like I get in the washout. It's been my experience that the one yard buggies from the rental places use pea gravel. Pea gravel's great if you're putting thick posts in thin holes.

Mixing in a mixer is a lot like real life. One of the ironies of it all is you sometimes need your sharpest cookie doing the dumbest job.
 

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   / Mixing concrete with a concrete mixer, 101 #2  
Great explanation, Harve. Some of it I guessed. All of it was informative.

I've gotten to the same conclusions, myself, when I think about some of the things I want to do. Many of them will just be too darn small to order up a truck, even a "short load". Unlike yours, all of my projects will be in the same small area. I've given some thought to setting up a couple of bins for sand and gravel where I can keep a stockpile of material ready for any time I happen to need it. But, I can't shovel the stuff any more.

So, my next question is to your ingenuity, because I know you've thought about this. What kind of easier way is there to handle the material and load the mixer? Something I can load with my FEL? Remember, the furtherest I would have to move the mix would be about 600', so I can set up something more or less permanent. Some kind of hoppers? Some kind of conveyer? Of course, it can't be too expensive to set up, or else it wouldn't be a savings any longer.

Second, I think you've shown some pictures of Iris's hopper for shuttling the mix in the past. I'd have to do something like that but adapt it so it fits in my bucket, because the TC18 doesn't have a bucket quick release. And, of course, I wouldn't be able to haul as much, because the weight of the bucket, the hopper and the load of concrete can't be much more than 850#. It might be better for me to figure out some sort of trailer-mounted hopper.

Ah, I'm just dreaming. But, the answers (from anyone, not just Harve) might solve some problems for me and a bunch of other TBN'ers.
 
   / Mixing concrete with a concrete mixer, 101 #3  
Hi Don,

How much concrete are you planning on pouring?

I have a Home Depot electric mixer that cost a few hundred bucks. Nothing in the league like what Harvey uses, but I'm not in that class either. Harvey is a pro and does this full time. He's got it down to an art and has perfected it.

Concrete is like most anything else you do, the more practice you get with it, the easier it is to do. For guys like you and me, we just don't get that kind of experience to reach Harvey's level.

I know I can handle a yard on my own fairly easy. Two yards is a workout and anything over that I'm pushing things. Most sand/gravel yards will sell you sand and gravel already mixed with the larger rock ready to go. Price is around $30 to $40 a yard. Then the sacks of Portland Cement bring your mix up another $10 a yard, so the savings are for real when you mix your own.

I've also found that doing a yard or two, and paying twice that amount for material to have it already mixed and in a buggy ready to pour is cheap money.

You can wear yourself out shoveling it into the mixer and wheeling it to the site all day long, then not have any energy left to finish it off real nice. With a buggy, I can pour a yard on the hottest day and be done in an hour.

If your going to do more than two yards, you better have some friends to help spread and smooth cause it will set faster than you can mix it. For jobs like that I call in the pros and let them do it.

As for building a way to haul concrete in your FEL, why not build a box of 3/4 plywood similar to what Harvey did from steel. It would last plenty long enough and allow you to direct your pours exactly where you want them, especially if you put a spout on it like Harvey did.

Just a few thoughts,
Eddie
 
   / Mixing concrete with a concrete mixer, 101 #4  
I'm way behind you in the learning curve Harv, but not so far behind in the aging so I guess it's a losing battle for me.

In doing my brick work this summer I did most of the mixing in a pan with a hoe. Use pre-mix mortar to keep life simple. Things sped up somewhat when my wife tended to the mixing but she wasn't reliable due to other household duties.

My biggest productivity came in a weekend blitz to finish when I rented an electric mixer from Home Depot. That thing was the cat's meow, the dog's bark, the snake's hiss. Add the wife to that mix and we were humming.

Now this little mixer was about six cubic feet and we were only doing two bags of premix at a time. That niner of yours must really put out the mud!

Thanks for the info Harv, we're always learning something from you /forums/images/graemlins/smile.gif
 
   / Mixing concrete with a concrete mixer, 101 #5  
I have not priced one, but there is a 3 point PTO driven mixer on the market that may do the job for you. Not sure where I saw it but it is out there.
Farwell
 
   / Mixing concrete with a concrete mixer, 101 #6  
<font color="blue"> How much concrete are you planning on pouring? </font>

Think slabs like the one you did for your electrical boxes. First one I'll do is for a small pump house. Then, I'd like to do a little slab under my refueling rig. That might expand out some day to an area as large as a parking spot. There will be slabs for various other uses, all small. And, concrete ends for the driveway culvert I unstalled. I've been thinking about the best way to build raised garden beds, and here in Florida, I've pretty much decided to use concrete block, so I need some small footers and some mortar. If that works out, I might try some other small concrete block work.

I want to build -- don't laugh -- a small, maybe 3 holes, putt-putt golf course, a little at a time and as cheap as possible (I figure I can actually have a 6 hole course by putting holes at each end and playing in both directions).

If it gets as big as the aprons outside my barn doors or outside the carport, I'll have someone do it for me.

I can build the forms, run the tractor, run the mixer, dump the load if I have a hopper, and screed and float a small area. I can figure out how to lift the cement into the mixer, but I cannot shovel the sand and gravel -- I have to figure out a mechanical way to do it (darned heart stuff is a nuisance - I do NOT want to set the defibrillator off again). If I have to use ready-mix every time I need a small amount, those jobs simply won't get done - my budget is limited.
 
   / Mixing concrete with a concrete mixer, 101 #7  
</font><font color="blue" class="small">( Concrete gets a lot of it's strength from the rock used. )</font>


The ultimate strength of concrete is dependant on the stength of the aggraragate.

Egon /forums/images/graemlins/grin.gif
 
   / Mixing concrete with a concrete mixer, 101
  • Thread Starter
#8  
Evening Don,

You don't know how good it makes me feel seeing you ask questions about work. It wasn't too long ago we were really worried about your not even being able to think about work.

What we're looking at two problems. One of course if the mixing of the concrete. For your situation a six cubic foot mixer would be great. A bud of mine says small mixers go through an ag auction he attends regularly. He says they go through all the time and at a good price. A good concrete mixer will run you three grand plus new.

What I'd suggest is making a bucket similar to mine. And since you don't have quick attach you can use a quick connect system. Say something where you have a bucket made like mine that fits in your FEL. If you had two lips at the back of the insert that fit over your FEL then you could use some set screws to attach or connect. The same kind of design could be used for the bottom front.

You do want to be able to shake the insert to dispense the concrete. Sometimes you want it stiff and it needs a little encouragement to get it out of the insert.

So if you buy a mixer right you should be able to sell it for what it cost you. Your insert's cost is also recoverable if you build it right. You're not the only bass in the creek who wants to mix and pour your own concrete.

The problem with not using a shovel to feed the mixer is you can't just put it all in there at once and expect a good mixture. It needs to be added at a consistant pace so that the mix is consistant.

I've had situations where a know-nothing-and-won't-ever-learn--ever has put the material in too quickly and you almost have to take the barrel apart to get the stuff out. Believe it or not you can have a dry knot of material in the bottom and a wet mess on top.

No fun.

I guess you could make a shovel style scoop for the FEL that will only allow you to pick up a small amount each load and use that to fill the mixer.

Another thing is if you get a nine cubic footer right you can mix small loads with it. I haven't seen anything in writing that says you have to mix a full load each time or they put you in jail etc.

My father in his early to middle seventies mixed the size of loads you're considering---in a wheelbarrow.

But we need to keep in mind Dad road Hard Work into the ground and then cussed her for being so easy.
 
   / Mixing concrete with a concrete mixer, 101 #9  
I don't have a solution for you, but had a similar situation that may give you some ideas.

I had a number of piers to pour for an elevated deck. Let's just say that I badly underestimated the number of bags of sackcrete I'd need. Four yards later I had a system that kind of worked and you may be able to adapt to your needs.

I bought the $250 Home Depot special mixer that (no kidding) runs on cooking oil and electricity. Worked great, but it was really a pain humping the bags in to the mixer.

I disassembled the mixer and mounted the part that piviots on a 4x4 lumber frame that I mounted in the bucket of my B2410 with ratchet straps. Plug in the mixer with an extension cord and toss in a couple of bags and a squirt of water. Mix well, unplug the cord and drive to the form - dump - repeat (over and over and over).

Since I was hauling the sacks on my flatbed trailer, it didn't take long to build a trough from three 2x12's. Drive the mixer up to one end of the trough, set a couple of bags in the trough and attack them with a hoe and push the contents in to the drum.

My "system" still involved lifting the bags off the pile and setting them on the knee-high trough, but it is a heck of a lot easier to push the dry mix down the trough with a hoe than to shovel or lift it in. Installing the mixer in the bucket also eliminates the problem of building a box to pour from.

I'd attach some pictures, but it wasn't really the kind of operation I wanted to brag on. <Grin>

Good luck and I hope this gives you some ideas.

John
 
   / Mixing concrete with a concrete mixer, 101 #10  
It all gives me good ideas. I think, for my needs, I might be better off with the bag mixes. That way I can avoid the mess that Harve described if the stuff is fed in the wrong proportions/speeds. Also, the proportions will always be more or less correct. It might not have the quality of different consistencies that Harve depends on, but I suspect it will be a while before I have enough "seat time" to know the difference.

The next advantage of the bag mixes is handling. I'm not supposed to lift anything, but I can tumble them. I think what I need is some sort of conveyor that can take the bags to a height that they can be opened and poured into the mixer.

I really like the idea of putting the entire mixer into the bucket. The 6 cubic foot mixer that Harve recommended has a capacity below 500 pounds; even if the mixer itself weighs 300 pounds, my little TC18's FEL will handle it. Pull up to the conveyor, tilt the mixer up, open the bags and pour them in, mix, then tilt the bucket and poun. Use the mixer itself for a hopper. If my little Coleman 1850 generator provides enough juice to run it, I can mix while rolling by mounting the generator on the back as part of the counterweight!

To try the idea out, I'm going to look for a used 6 cu ft electric mixer and build a rack to mount it in the bucket. Then, I'll just lower the bucket to the level of my tailgate to put the mix in; it it works I can build a small conveyor.

Off to EBay to see what I can find...
 
 
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