Has anyone built a 1+ yard concrete mixer?

[napabavarian]

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.

Are you talking about the cylindrical rotating mixers? I do intend to look at them, however I havn't figured out how I could load the dry material into that style mixer yet, it is a great way to go if I can figure t out, just make it with 8-12 flat sides and roughly a 1.5 yard capacity.

 

[napabavarian]

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.

Are you talking about the cylindrical rotating mixers? I do intend to look at them, however I havn't figured out how I could load the dry material into that style mixer yet, it is a great way to go if I can figure t out, just make it with 8-12 flat sides and roughly a 1.5 yard capacity.

 

[RonMar]

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.

Cost per post was why I was looking at concrete. I have roughly 2400' of property line so I need in excess of 150 posts(at a minimum) at 10' spacing across the front with wood rails for show and 20' spacing around back with 3-4 strands of wire. I was going to cast them round, which is a little more efficient use of material.

IF I casted them at one location with a eye bolt in the top for lifting, they would be easy to move, but to place them in the location, I would need a big enough hole to allow gravel to be added around them and be packed in place. Gravel adds to the cost... Concrete with gravel agg weighs about 150# per CU/FT and a 5"X5"X96" post is aroung 1.4 CU/FT. I would need a way to lift an 8' long very heavy pole up and into the hole as well as a pretty straight hole. The "U" or eye bolt would add to the per-unit cost.

Most inexpensive option that gets me a 5' fence, is using 8' PT poles that I can get for $3.99 each if I buy in bulk/greater than 100EA. Add to that gravel/crete to set them and the wire hardware, and I am probably a ways over $5 per post for just materials. Those posts will have to be replaced in about 10 years or so in our moist climate.

By augering a 6" hole, 3' deep and placing a 5' tall mould over it held upright with tripod legs, I could lift the mixed crete high enough with my FEL to pour into the mould. By pouring into the augered hole, there would be no additional hole packing/gravel required. The hole would also not need to be absolutely straight, just start at the correct spot on the ground. By casting 3-4 pieces of rubber hose into the mould(held rigid during the casting with all-thread that also helps to hold the mould halvs together), there would be no need for wire hardware or a problem with attaching it to the concrete. Just thread the wire thru the holes. I havn't tried this and have no idea how it will work out long term, it is just an idea. I have seen it done on a horse fence using wood posts though.

An 8' post with 6" dia for 3' and 5" dia for the remaining 5' would have around 1.2 CU/FT of volume. On sale, I can get 60# bags of sacrete(.4 CU/FT) for under $2. That is $6 per post, but I think they will last a little longer than 10 years, so this job may only need to be done once(I like that part). I should also be able to beat this price a bit if I get dry readi-mix in bulk from a local supplier. I might also be able to decrease the post diameter, but I havn't experimented with that yet to see how strong a 4" post is compared to a 5" post and how either compare to 4" diameter teated post or metal "T" post.

 

[DRL]

Ron
Don"t forget the re-bar cost. Will your forms be reusable?
DRL

 

[mjncad]

Are you talking about the cylindrical rotating mixers? I do intend to look at them, however I havn't figured out how I could load the dry material into that style mixer yet, it is a great way to go if I can figure t out, just make it with 8-12 flat sides and roughly a 1.5 yard capacity.

Yes, United Rental's towable mixers are mini versions of conventional barrel type transit mixers we see day-in, day-out.

 

[RonMar]

Ron
Don"t forget the re-bar cost. Will your forms be reusable?
DRL

No re-bar, just larger aggregate. I had the opportunity a while back to break up a few parking lot concrete barrier posts that had been dug up for an expansion. We had to break them up to lift them into a truck to remove them and they were real mothers. About 6-7' long and 10+ inches in diameter. No Re-bar and took quite a bit of sweat to crack thru with sledge hammers.

How strong does a fence post that supports wire have to be? One of the reasons I will be making some test castings for destructive testing.

Yes, the forms will be reuseable, most likley of PVC with some steel re-enforcement where the halfs are joined.

 

[Red55]

Ron- just an idea but have you considered using some pvc pipe as a mold and leaving it in place? This would eliminate moving the pole after casting and would give you a nice smooth finish, Yes the pipe would add to cost but maybe that drainage pipe (on sale $4-5) cut in half into two pieces will actually be a break even price because less concrete. And I would add fibers to the mud for strength. -Ed

 

[Brad_Blazer]

Some concrete mixer links. I googled "cubic yard concrete mixer"
2CL 3 Yard Portable Concrete Batch Plant - Mix Right
Monolithic Marketplace - Monolithic Portable Concrete Mixer

Ron,

I would seriously consider making a batch mold for the posts and tamping them in place with the dirt from the holes. A shallow box made of 2x6's to look like a stud wall with 6" between the studs, pinned together for disassembly would allow you to make a bunch at once. The labor saved there would make up for the tamping. I like the idea of some steel in the posts. 1 small rebar down the middle or 1 on each side if you have rail pockets. You can probably save 50% on concrete by buying portland cement and getting bulk sand and aggregete.

Are you going to mold in pockets for the rails? A coffee can or section of downspout can be fixed in the mold and left in the post.

I just finished tamping 260 wood posts around a 10ac field. (I know how the cost adds up.) When it was dry this tamper worked really well:

I got it cheap from a local HF returns reseller. Here are some at HF:
Harbor Freight Tools - Quality Tools at the Lowest Prices
Harbor Freight Tools - Quality Tools at the Lowest Prices

 

[DRL]

Ron
I would never have though about not using rebar. Will be interested to hear about your destructive testing results. You know that concrete takes a long time to cure to full strength. I think I remember something like 60% or 70% strength after a month, and more than a year for full strength. So you better get those test posts poured if you are going to do the fencing this
summer.
I like Ed's idea of leaving the PVC pipe in place. I'll bet you could find something cheap to use, like mailing tubes. Also leaving the forms on will make the concrete stronger because it cures slower.

DRL

 

[RonMar]

Thanks, All good ideas IRT the fence posts. I was planning on casting in pockets for the wood rails on the front posts, but the posts around back will be strictly to suport electric fence wire. I had initially thought of PVC, but there is sun degredation to contend with using regular PVC pipe as it is not meant to remain exposed to the suns UV rays. PVC would also double the cost per post. Steel would also add significantly to the cost(nothing that is trucked out onto the Olympic Peninsula is cheap)

With a larger diameter and larger aggregate, I may be able to achieve an adequately strong structure without steel. I haven't ever worked with the fiber re-enforcement materials, but that may also be a strengthing measure. It is not like these have to support any active load like a garage floor or load bearing wall. And if something is going to run into it hard enough to break/shear it, perhaps it is better that it does shear... I am familliar with the cure time of Concrete. They will stand for a few months before I start abusing them. I don't plan on doing this project this summer.

If you google "concrete fence post", you can find some info on homemade ones, some with wire re-enforcement, some without. There was a company doing a system called "fence bag" but I can't find their link anymore. Their old site gave me the idea of casting in place. Basically they used the continuous plastic bag material as a mould, held up with a tripod and a small round form the the top held the mouth of the bag open. The weight of the concrete held the bag material in a tube shape. A razor blade was used to cut away the bag material after the post was fully cured. But there was no way to cast in features using this method, it just gave you a plain round post.