It will run on angle iron tracks attached to a long skinny mortar box.
The rear wheelbase will be widened so that the wheels are wider than the tynes. Another set of wheels will be mounted beneath the smaller pulley. So only the wheels will touch the mortar box.
I should be able to mix around 20 cubic feet in one go. That's about one ton of material.
If the auger only has to mix and pug the materials without the worry of lumping it should be able to produce a more uniform product.
A thought off the top of my head: Instead of a long trough how about using a vertical round tub which can rotate and the rotation be driven by an attachment to the outside of the tines which will ride on the top outside edge of the tub. The inside of the tiller tines center tube will be attached to a post or somesuch which allows a pivot point in the center of the tub. As I recall tillers like that have like 26” or 28” wide tines so the tub will hold a large volume and will be able to achieve homogenization easier. I see several scenarios of how this could be made. I'd angle the tine drive so it would be pulling the slurry towards the middle rather than placed at a right angle to the tub edge. In other words the leading tine will be closer to the tub edge than the trailing tine.
Keep in mind that the oil seal where the tine shaft exits the drive box is probably not waterproof as it is designed to keep oil in rather than water out so it may be best not to submerge it in the slurry. Of course you can always build longer custom length times to extend deeper into a container.
The long trough definitely has the advantage of being low tech but the circular tub has the advantage of being able to mix without someone hanging onto the tiller and walking back and forth.
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.
Tillers with dead motors are often free. Add an electric motor and you have a good indoor mixer.
Dale Hodgins wrote: One batch of clay slurry will allow me to produce about 3 tons of finished cob.
For sure I have never used clay slip or even heard of it before a couple of months ago but I was under the impression that the clay one would use for clay slip is much closer to pure clay than one would use for cob. I definitely see your point on slaking the clay for slip.
Is the suggestion that essentially one mix up a batch of clay slip then complete a batch of cob by adding the slaked clay to sand and straw? It’s an interesting thought. As I think on it, though, I’m not sure the advantage is there for mechanized mixing. I see a real advantage if those mixing by feet were to slake the clay fraction some amount of time before finishing the cob mix. Seems to me it would make the mixing by feet somewhat easier and faster.
When using a trommel for wood chip clay and straw clay, it is essential that a slip be made.
The rocket stove dosen't use straw so it can all be mixed with the rototiller.
The clay emulsifys with time spent in water and with abrasive action. The inclusion of pea gravel can help with breaking up lumps. It can be filtered out or not depending on what's needed.
Pre soaking is probably more important with foot mixing due to limited power.The machine can greatly reduce soak time since it can chop through lumps and pebbles can be included without worry about foot damage.
For me, not having to carefully sort my ingredients is very important. I intend to use tampers and forms so the mix can be abrasive and sharp stones won't matter any more than they would in concrete.
I intend to keep my shoes and pants on for the duration, just like when I work on other projects.
Doug Piltingsrud, PhD, of Sustainable Housing Resources, LLC presenting information on research into light straw/clay construction at the 22nd Annual Energy Fair in Custer, Wisconsin on June 18, 2011. Taped and edited by Duane Brewer for JATV.
Very informative video.
The video below demonstrates the technique.
Basically the same thing could be accomplished in one good sized tank with a pto driven paddle auger.If the tank were higher than the trommel, the slip could be gravity fed. The bottom 10% of the tank would hold the settled sand and pebbles. This could be dumped or used in a batch of cob.
When I first saw it I was quite enamored with the idea. Then I counted all the people and machines. This is a conventionaly framed building. It's unclear whether the surfaces will be naturally finished or if the straw clay is just insulation. If it is just insulation and the building will be covered in siding or stucco then I'm not sure that the process makes economic sense. This was a community effort and a learning experience.
For me to employ the machines alone would be cost prohibitive. If I was to show up at a job site with all of that and 10 people it would need to be charged out at around $400 per hour.
It means an air driven tamper rather than a hand held hammer to tamp the earth into tires. It is using a “pug mixer” to mix clay and aggregate for a rammed earth wall. A chain saw and a good splitter to prepare the wood for a cord wood wall seems a great idea.
Someday we may get back to a slower pace where the average person feels they have time for hand made one of a kind homes. I hope it is soon. However until then we are asking the rest of the world to leap a large canyon of thinking to get to our side. Showing the rest of the world a better way and how to use their tools to build it is akin to building a bridge over said canyon
I hope others will weigh in on this.
Also, look into GRID BEAM. It has been developing for over 40 years and the folks who use GRID BEAM have built many types of "far out" machines such as solar vehicles, solar yard carts. indoor furniture and much more.
But, I see where you're going. I'd thought of using a cement mixer but those who've tried it say that it works but it's not the best solution because the cob sticks to the sides. The pros build their own purpose built machines.
I LOVE the idea of using a set of tiller tines. I hadn't heard that. One guy rigged up a trailor to an old rear end of a truck. Then he set it up so that when he locked in the trailor he could drive around and mix the cob with a lawnmower blade attached to the drive train of the differential.
If I were you I'd start with the tiller idea... It's made to work in that kind of soil and do exactly what you're trying to do with cob. Maybe invert the tines and mount them in some kind of hopper.
I've also heard good things about an auger and a drum. Fill the drum with the material and auger the crap out of it. If you reverse the auger direction you should be essentially kneading the cob which is what you want.
Check out the thread about papercrete and the other about tow behind mixers.
On an unrelated note, has anyone used a mortar bag while fixing earthen plasters? Mine is pictured below. Works in the same manner as a cake decorater. Like a calking gun that you twist and squeeze.
Brian Knight wrote:Mechanization to reduce labor costs for green building techniques? To me that means SIPS.
Use straw bales instead of foam or recycled paper bricks and the SIP's. There is also a paperfoam material, http://www.paperfoam.com/, that may be a substitute for the regular foam.
Brian Knight wrote:
Oak Ridge National Labs has done the most research on thermal mass benefits and from what I recall, Bakersfield CA and Phoenix are the only two areas of the US that thermal mass only walls can make sense. Both of which are high desert areas with consistent wide dirurnal swings.
Best example yet of the failure of government research! I cannot picture any way in which a thermal mass wall could be built without an insulative value. Can you?
There's also a lot more high desert with wide swings than Bakersfield and Phoenix.
Brian Knight wrote:I would say the major deficiency of NA home building is air infiltration followed by insulation. Thermal Mass is way down the list after the likes of attached garages, ducts in unconditioned spaces, and ventilated crawls and attics.
Those are all problems, yep. But...
Brian Knight wrote:I agree with carpeting being a bad idea but forced air is one of the greatest things most homes can have.
This is my major beef. Forced air heat is the absolute worst, least efficient way to heat a house, bar none. I don't care if it's one of those modern 99% efficient furnaces that can vent out PVC. It's still less efficient than the clunkiest old hot water radiant system.
Why? The key is radiation. Radiant heat. I can measure the air temp in two houses... say it's 62. In a forced air house, that will feel frigid. In a radiant house, that will feel like 70. Radiant heat warms everything; forced air heats only the air... the very least imaginable reservoir of heat! Water can hold heat. So can brick, stone, concrete, adobe... hence the term, thermal mass.
Yes, forced air systems are cheap. They're cheap because they're crap. As Dale points out, it's a Band-Aid for bad house design. So is air conditioning. If it were up to me, code would ban them. Maybe then architects would start designing houses that work.
There is nowhere in the lower 48 where passive solar heating does not work. A few years ago, I built a house in the Colorado mountains, 10,000' elevation, where -30F isn't uncommon in winter. The backup boiler has never been used. It's just a combination of south glazing, good insulation... and lots of thermal mass.
Marty Pixley wrote:
It means an air driven tamper rather than a hand held hammer to tamp the earth into tires.
I was just watching a documentary yesterday about the "Earthship" houses. I'm watching guys beat dirt into tires with sledgehammers. And I'm thinking, these guys need a pneumatic tamper! They already use mortar mixers, jackhammers, power saws... so it's not like they shun power tools.
Enjoying this thread...Dale, with respect to mechanization, I see how straw can gum up the works, but you have talked about woodchip slip - seems to me this would be easier to mechanize since no issues with gumming up the mixing paddles, etc....?
I see the new thread concerning this and will stay tuned there as well.
Mariah Wallener, let's race. If I get all of my paperwork in order first, you're invited to spend some time at my place to see how it works out. If you're ready first I'll lend a hand and any equipment that I have at that point. On your marks, get set ---- BUILD.
Still wavering as to whether to do cob, straw bale/cob, or wood chip slip infill....permies.com will help me make up my mind, lol.
I wanted to install under-floor radiant heat and solar collectors, but they were too expensive. I bought a high-efficiency condensing forced air furnace and new ductwork instead, at a significantly lower price than just the price of tubing, cheap hot water heater, pump and controller, installed -- forget the solar collectors. Quite often, "sustainable" alternatives tend to be out of reach of modest incomes. It takes Green to be Green.
I remember seeing the straw-clay setup shown in the Wisconsin video somewhere before. Even with the mechanization he has implemented, it still looks very labor intensive, but much less than before. I think his goal was not so much efficiency of labor as it was consistency in the product. I am guessing that some labor saving machines could be included in the mix. Perhaps some conveyor belts could be used at the tumbler, or rigged to stuff the wall cavities? I watched a short video of a man covering straw with slip by hand in a small bucket then stuffing it into a 3.5" wall cavity in 2' lifts. It was excruciating to watch. Wouldn't it be easier to prefabricate blocks or panels that would fit in the wall cavity, then trim if needed and stuff any gaps with handfulls of straw clay?
Has anyone used Straw Jet products?
Mechanizing green building can just mean so many things. To me, the greenest homes are those that use the least amount of monthly, energy and have the healthiest indoor air quality. Monthly, energy use by homes and buildings is arguably the biggest source of our environmental footprint. By mechanizing something, we are seeking to reduce labor or use a machine to help us do something.
Perhaps the pre-fab movement has the biggest claim to mechanizing green building. Not that even the most advanced pre-fab companies are doing enough to reduce monthly, energy use because 99.9% could be doing substantially better. SIPs is panelization, which is a form of pre-fab, and much more flexible and easily customizable. It also uses the exact same carpentry labor techniques that make up almost all homes in this country. Its only a matter of time before the "evil foam" is replaced with more eco-friendly materials. Its 95% air. The blowing agents are currently being improved in huge ways. I personally feel that the building envelope is one of the best uses for this precious and controversial resource. It is the most permanent and hardest to improve parts of a home and impacts decades, maybe centuries worth of dirty monthly energy use into the future.
I find the backlash against "forced air" surprising. For those of you that do not require AC, congratulations. For the rest of us in the East, AC with dehumidification is not something we are willing to live without (personally, I use mine very little). Good luck doing this without "forced air". Geothermal heat pumps are an extrememly efficient means of using foced air heating. Some forced air systems use solar thermal for their heating fuel source. Many more use wood.
I think most building scientists and Indoor Air Quality experts would agree with me that an ERV or HRV is one of the best mechanized devices a new home can have for indoor air quality. It to is "forced air". Some of the greenest, most high performance homes in Europe and NA are Passive House certified and they require an HRV or ERV: "forced air". A properly designed home with a good building envelope and a Manual J calculation implemented forced air system is very efficient and the "blowing air" is almost completely unnoticable. Best practice duct design keeps ducts clean by keeping the filters at the return grills and construction debris out during construction. Yesterday, I tore into a 40 year old duct system at the bottom of an elbow from two stories up and it was completely clean and dust free.
The Building Envelope is the most important thing for a vast majority of green homes or buildings. Not thermal mass, not "radiant" heat but an airtight, thermal bridge minimized envelope. For those of you that are unclear about this, check out the building science page of my website, or some of the other good building science sites; Buiding Science Corporation, Green Building Talk, Green Building Advisor. I really cant argue with those that dont accept scientific based studies like those from Oak Ridge National Labs.
As the biggest side track of this lenghty post I invite yall to check out my new article in Green Building Advisor: Cost-Effective Passive Solar Design http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/cost-effective-passive-solar-design
It looks at the most mechanized-free way of heating available to us. Surprise alert: the subheading says "include some thermal mass".
For those of you that would like to engage in some good hearted debate about all this, please start a new thread because I obviously dont belong in an Earthen wall thread!
Brian Knight wrote:Thanks Andrew. I dont want to hijack Dales wonderful thread so I will keep my comments here shorter than I want, now and in the future. I think this thread would be better titled: mechanized techniques for earthen wall construction.
Mechanizing green building can just mean so many things. To me, the greenest homes are those that use the least amount of monthly, energy and have the healthiest indoor air quality.
For those of you that would like to engage in some good hearted debate about all this, please start a new thread because I obviously dont belong in an Earthen wall thread!
Hi Brian --- I don't think any of us own threads just because we start them and there's no reason why we can't discuss all manner of green building. The "Mechanized" part of the title doesn't mean earth walls. If you use a crane, a Bobcat, or a pneumatic tamper in your process, you're mechanized.
I've concentrated on earthwalls because that's where I see the greatest need for improvement. Some of the laborious processes I've seen are quite entrenched within a crowd who are often reluctant to pursue better methods. I've recieved scoldings from purists who insist I'll go to hell for stirring the pot. To me, rigidity and mental laziness which leads to needless labour expenditures are an embarrassing aspect of the green building movement. I find myself constantly explaining these glaring obstacles to widespread acceptance of green building techniques.
My situation is far different than yours regarding forced air heat. 85F is a really hot summer day here so AC is not part of the equation. I have lived with some really horrible forced air systems. With my open concept ,solar and RMH powered home, there's simply no need for ducts. I accept that others like them and the machines they serve. My property can produce far more energy than I'll ever use so going to great lengths and expense to save energy isn't a top priority. The sun will provide most of my heating and eventually I'll tap into my hydro potential. All of this energy is currently being wasted so my home will use it and draw nothing from off farm.
Another huge difference in our situations is that I don't need to build something that looks or feels at all conventional or that would be widely accepted as the proper way to build, since I am my own customer and anyone who doesn't like it can eat sh--. I say things like this regularly. This works for me professionally and personally but many business people must use a more diplomatic approach. When I eventually write something documenting my innovations, It will be a no holds barred rant about efficiency, drifting to diatribe when I make comparisons to mixing muck in a pail.
I assume something similar could be cobbled together to handle other forms of cellulose, like wood chips, sawdust, excelsior, hulls/husks, etc.
I will again mention MgO, or an MgO based cement, as a possible addition to the clay slip. If the internet articles are to be believed (and who would ever doubt what one finds on the internet?), it should considerably shorten drying time and eliminate shrinkage, mold and rot. My main concern with using it would be it gumming up the works as it thickens and not getting it cleaned up before it hardens (sell it as sculpture?).
Why not just use regular bales and coat them with clay ?
I got called out to look at this glorious mess today. There are enough cedar slabs to fill 15 or 20 demolition bins.This is 3 or 4 times as much as I will need for the house. This is exactly the product that I have spoken of before which will be incorporated with my mix of sawdust, chips and clay. With slabs it is possible to stretch the materials that must be mixed up with water. This should use less labour and produce a dryer wall so long as the slabs are reasonably dry. Slabs of fir and maple are valued for firewood and by companies that make bagged soil mixes. But cedar is fast burning and not in great demand for firewood and it's alleopathic properties make it worthless as a soil component.
If this pile of wood were in Mexico City, Cairo or in many other wood poor areas, people would fight for it. The owner of this small mill will spend $6000 - $9000 to get rid of it. So you can see why I intend to build, heat, produce energy and build soil with wood. There's mountains of it and I'm well positioned to tap into this resource.
This sawmill is a 2 man operation based on a semi-portable bandsaw. They've accumulated slabs for several years in an industrial area where a slab fire would be disasterous. The landlord and fire officials are involved in saving these guys from themselves. The yard has nowhere left to pile lumber and trucks need more space. I've been to mills employing 20 guys that had less scrap laying around and more space for equipment.
Unfortunately, this stuff is 70 miles from where I need it. When a similar pile comes up in my area I should be able to squeeze a few thousand $ from it and have something I need dropped at the farm in demo bins.
--- Later the next day --- I got the job and am holding a firewood free for all, as a means of cleanig this up. Some ads and phone calls have led to about 30 people who want it for firewood, raised bed building, fencing etc. Signs and the visual spectacle will draw many in droves.It's going to be a "Gong Show" as every firewood hound in Victoria scrambles for the best pickings. My job is to keep the peace, organize all of the vehicles, prevent theft of the saleable lumber and make sure everyone survives.
I accept that you feel blocks are not a good trade-off. I may still try it, if I am ever presented with the opportunity. I don't see much difference between a properly bonded block wall and filling wall cavities in lifts, other than convenience.
I will always be a little leery about the longevity of hay bales, particularly clay entombed ones. I remember reading, decades ago, about a hay bale house where the bales rotted out, leaving a beautiful grid of mortar. Proper straw-clay, or any other type of cellulose-clay should do much to lessen the possibility of rot and decay. (I stress that this is only my opinion and I am in no way inviting a discussion, or otherwise, on the merits of hay bales vs. whatever.)
Could a wall be filled while it is still laying on the deck? (That would be a conventional stud wall.) Would it be too heavy to tilt upright after being filled? They make concrete walls that way (sans lumber), so I assume it is only a matter of using the proper tools and methods.
Being in a wood scarce area, it pains me to see such waste, but that is how it goes when there is an abundance of a particular commodity and no way to economically transfer it to an area of scarcity. Would those cedar slabs make good siding, if you weren't too picky? No local market for cedar mulch? Perhaps they could build a charcoal retort?
A crane would be required to hoist walls filled with such heavy material and the framing members would need to be very large and strong to withstand the lift.
Only straw bales are used in modern home construction. Hay is too attractive as food for vermin.
Attach long metal pipes to the corners of the wall panel, bringing the other ends together to a point. It will resemble a pyramid. Attach a rope/cable/chain/tow strap to the tip of the pyramid and pull in the direction you want the panel to be raised. You can use muscle power, a vehicle, a come-a-long, winch, whatever is appropriate and/or available. You can put pulleys in strategic places and adjust the location of the point to facilitate things. You may need to add pipes along the sides, if your panel is long and/or tall. You could work with two teams, one side pulling and the other pushing with bracing poles (don't let anyone under the wall at any point, and have the danger zone clearly marked).
I am sure there are other clever alternatives available, such as a tripod crane (recommended by one manufacturer for handling full-sized SIPs).
I don't know why one would need massive timbers. I would not necessarily recommend this technique for timber frame, though it still may work, with proper reinforcement. Once the straw-clay has set (not dried, that may take months), it should be stiff enough to maintain its shape (consider rice krispie squares, or granola bars). I don't know how long it would take to set. Addition of cement stabilizers would facilitate it. If the panel can't take being lifted, it will likely not handle wind (diaphragm pressure) well either. They were putting bamboo reinforcement in the straw-clay panels in one of the homes I looked at on the web the last couple of days.
If someone has the time and resources to test it out, it might make straw-clay (and other cellulose-clay alternatives) more inviting -- if it works.
I still think blocks would be less complicated, but that is just my opinion.
Please forgive my inadvertent use of the word "hay" instead of "straw".
Any ideas on how to make stuffing wall cavities less tedious?
I have a crane, so I tend to think of using it for anything heavy. Anyone who has a tractor with a front end loader is bound to find that using the loader is the best course of action in many situations.
It took discipline to do what I did next since every instinct said to count the loot. --- I slipped it into my pocket and then calmly sent my helper Amir on a clean up mission far from the basement. Then I locked the door and drew the curtains and carefully dismantled the entire ceiling myself. Didn't find another dime, but it was an exciting hour as I dreamt of hitting the mother lode.
At the end of the day I sent Amir off and I counted the loot. ----- $1350 ----- much less than I had imagined. Most of it was $5 bills, so the envelopes were quite bulky. I spent some time poking around every concievable hiding spot in the house. Nothing.
The newest bills were from 1969, so this was a long forgotten stash. The $20 bill in the photo is from the 1950s. Canadian money is constantly changing in order to keep ahead of counterfeiters. Artists compete to get their work on the money. Prominent natural features are usually depicted. Colour variations help the visually impaired to not accidentally pass a 50 for a 5. Whenever I handle American money,I'm very carefull to watch the numbers since it all looks the same.
The materials in the bucket were reduced and mixed with a combination of pushing with the bucket and driving over it with concrete as a base. On soft ground it would probably be more difficult.
There is a mill 1 mile from my place which tends to have a higher % of sawdust in their scrap pile. When I checked 2 weeks ago there was about 400 cubic meters piled by the mill, so not something that will run out. I envision preparing 30 yard bins of pre-mixed Matrix, which would arrive ready to use. They have a giant loader that could hold a car, so it makes sense to use that as the primary mixer. The stuff in this bin has the wood and sawdust,but no clay.
So my solution is going to be a mechanized version of Abe's rapidobe http://velacreations.blogspot.com/2011/12/rapidobe.html
I will use a bobcat or loader to gather and fill the forms. I will use cattle panels and T posts for the forms. I will overcome the low quality with great quantity. Three foot wide walls or greater where they are load bearing. Wide enough I can run a compactor inside.
There's a half million dollar pump truck, 2 cranes, 2 trucks that carry steel beams and wood blocks, and a service truck. Barges are also sometimes employed. I live on site and park my van in the middle of the most expensive stuff, since theft and vandalism are a constant risk.
Being 100% recycled, these buildings are ultra green.
The clean slice pictured below is about 1/5 of the old Collwood pub, which is the only building in a strip mall being saved In advance of a 1 billion dollar redevelopment project.