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Cob mixing with animal power  RSS feed

 
Dale Hodgins
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Location: Victoria British Columbia-Canada
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    I've just invented a clog free automatic cob mixing machine.

      After watching a few videos of people trudging through the mixing process I figured there must be a better way. Some have had luck with using tractors and rototillers but gumming up of the machinery sometimes occurs. So I googled cob houses in England/history to see if they used animals. Turns out horses and oxen were often led back and forth through the mix and no doubt they added some manure to it.

     Now the automatic part.    Most large equestrian facilities have automatic horse walkers. And many of these walkers have become obsolete since this well-heeled crowd have gone in for horse bathing facilities and moving gate contraptions instead of the old big wheel type. Perfectly good walkers are available for $1000. You could attach your animals to this after spreading all of the cob ingredients and mix tons of material at once. Once you're done building, sell your machine to another builder or turn it into a poor man's carnival ride with swings. We bought an old Riding Academy when I was 14 and I used to swing my younger siblings on one of these, great fun. Alternatively you could harness a horse or two to this device and turn it into an electric generator. One of the most common issues for people who keep horses for pets is that these animals get lazy and fat. This gives these otherwise idle animals a useful job. Or as my hippie friend says it turns them into slaves

    For a simple manual version of this device . Bury an old trailer axle in the ground like a fence post leaving about 4 feet sticking up. Attach two poles on top of the wheel in a cross shape and attach lead ropes to the four ends. You now have a poor man's horse walker. Attach your horses, cows, goats or children and lead the strongest or most dominant animal in circles and the others will follow. Now a little kid leading these animals can make cob faster than a dozen hard-working adults.
 
Kathleen Sanderson
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That actually sounds like a good idea, although goats wouldn't work (they don't like to get their feet wet/dirty).  But horses, ponies, or cows should work.  Just don't mix more cob than you can put up in one day.

Kathleen
 
Dale Hodgins
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        I'll be using temporary forms similar to but not as strong as those used for rammed Earth. Materials will be moved to scaffolding with a front-end loader. I'm going to mix plenty of scrap wood as aggregate in the mix. This should allow me to place large quantities of material per day. I have yet to see a building process that couldn't be improved through mechanization. Maybe igloo building
 
Dale Hodgins
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   Update.    My real estate agent put me in touch with a friend of his who wants to live on the property in his fifth wheel trailer. He has an excavator and will be paying all of his rent with digging duties. So I'll probably mix cob using the excavator in a draw towards you then push 20 feet with the extend a hoe, while knuckling down method. He's confident that he can mix 5 tons of material in under an hour. I'm a big fan of cob building but I can't bear the thought of hiring labor to fiddle in time doing something that should be done mechanically.

    If you're taking in a new tenant just before you build a house you kind of want them to own an excavator and other expensive toys

    The combination of excavator mixing, hoisting materials with my crane and my truss wall forming system and wood infused cob should make this one of the fastest most efficient cob builds ever. I'll be looking for a few helpers who can earn themselves a free years rent and they won't have to spend any of their work time mixing materials or lifting heavy stuff.
 
Dale Hodgins
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cobman wrote:
I think the main factor to remember when building with cob and or "green building" is that rushing any stage of the process  is wrong and you probably should just be building conventionally.

CobMan


 
Dale Hodgins
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  I'm definitely not going to build conventionally. I've been a part-time green builder for 20 years in that I build almost everything from components of buildings which I have salvaged. 15,000 tons recycled so far. This quantity of work would have never been accomplished had I chosen to shun machines. I'm phasing out of demolition in order to pursue two other related businesses. I will use my 24 passenger camping bus to take people to green building events and I will build many of them myself. As for rushing things,  it would be irresponsible to use anything but the most appropriate technology particularly if I'm working for someone else and being paid for my time.

    I've tested making cob with a Rototiller and it works fine. I've watched others on the Internet mix it with a front end loader and by driving over it with a Bobcat. If the excavator gets things mixed somewhat well, I'll finish the job with the Rototiller. From there a front end loader or my old crane will hoist the material onto scaffolding troughs so that it can be efficiently applied to the wall. If I want to know how the mix is doing I'll pick a piece up and examine it. After speaking to several people who have built with cob the best guesstimate is that 90% of the labor has to do with mixing the materials. Since my building is going to be straight lined and not have a gingerbread house look, that percentage would be even worse in my case. For me the cob is mortar and parging and the wood is the bricks. I have no emotional attachment to the material or the process and would gladly change my methodology for something more efficient. And that means financially efficient. Labor costs money.

    I'm going to do this mechanically. I'm only interested in the results of my labor and not in preserving any sort of tradition. Lefty Gurus don't interest me. Cob building is the most labor intensive method of constructing house walls that I have ever witnessed. I intend to change that and build my post and beam truss wall home with parged cordwood cob infill in record time. Temporary form boards attached to the posts will guide the placement of wood leaving a gap at each end which will be parged with cob. This will give me the insulation which wood affords without all of the fiddly mortar pointing typical of cordwood building. The addition of wood to the mix should reduce the amount of cob mix required by around 60%. Plenty of x-bracing will be hidden within the cob. I may conduct workshops at some point but in the initial stages I will not have access to unpaid labor. Even at minimum wage the little garden building which I watched a volunteer group build would have cost thousands of dollars had the labor been paid.
 
paul wheaton
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I deleted a coupla posts here.

I wanna remind folks of a few things. 

1)  When presenting your stuff, please take a bit of care to present it as "here is what I like" as opposed to "this is THE way".  Because if somebody has a position that is different than "THE way" then expressing that is sorta like entering into a confrontation.

2)  If you see something that is gonna be outside of my comfort zone, click on "report to moderator" instead of saying "you're kinda icky" - cuz I gotta then delete that post too.  I suppose if you really feel the need to post, you can say "paul's not gonna like that.  he's gonna say ______." and maybe link to something in the tinkering forum about that.  In the end I have to delete such a post, but maybe by then, the previous post will have been edited by the author. 

 
Dale Hodgins
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Cob Mountain. --- So a few months have passed since I was informed that the cob gods don't like innovation. Soil testing has shown that I need a mix containing 60% my own subsoil with equal parts clay and sand added to make up the remainder. I've decided to use my tenant's excavator to mix all of the earthen materials in one go. I have a well drained area of bare ground without top soil where a pile of 200 tons or so can sit for as long as need be. No straw or wood will be added at this time. As material is needed it will be rototilled and mixed with straw and wood chips. This will facilitate quick mixing with no measuring needed for individual batches. And nothing will rot or get mouldy. I'll probably pick up a tractor with a tiller and front end loader to do the final mix and build. I'm making a plaster mixer based on an old oil tank and the rototiller. Might use post hole auger for plaster mixing.
 
Marcus Harden
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Location: NE Oklahoma
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Dale,

I'd like to know how this turns out. I don't think you should be hurt by cob traditionalists. I think building a cob structure manually can be fun and fulfilling for some, but by and large I agree with you. Human progress and innovation shouldn't be inhibited because "this is the way it's always been done". Isn't that often a mentality that gets us into all kinds of quagmires?

From an environmentalist standpoint there's even less to complain about. Aside from the process of construction itself, the building you've constructed will have taken and will take far less energy to maintain and build on than a conventional structure. Also, should it be abandoned the materials will (for the greatest part) naturally degrade and have little to no impact on the surrounding area.

Point is, no matter what way you look at it, it's a step in the right direction.

Finally, cob now is just as intensive as any home was to build by hand at any other time. Think about it, before lumber yards, pre-fabbed framing, and all of the tools and innovations that came with them building a house was hard work. Turns out it still is. I think it's great someone is trying to make technology make a better home. I imagine in time there will be inventions that make building a cob home far less labor instinctive than it is now. Homes will go up quicker and be made better along the way.

Envision a world where modern building is heavily influenced by natural building. You consult an architect and they do a soil sample on your land and give you options as to the building methods in various places. Whether it be cob or rammed earth tires or a geodesic dome. The design takes the movement of the sun into consideration and yearly temperatures, soil temperature and permeability, etc. They design the structure and say you decide on cob. The builders rent a cob mixer from a home depot, there are special tools for cob building, and plasters that breath and are made from sustainable products simply dug up and mixed but that need little to no energy to make unlike concrete. A result of digging up the cob is a trench to lay PEX tubing for earth tubes. Vertical turbine wind generators are the fad in your neighborhood so you put one up. You hire a landscaping company that keeps a compost pile on your property (YOU DO NOTHING but add organic waste, they send out landscapers to turn it and manage it. Maybe reduce your monthly costs by buying back compost.) In addition your compost now heats your home. Perhaps toilet waste is connected to a community sewer that burns the methane produced for electricity in your neighborhood. The remaining waste is pumped to an algae farm as algae food which is harvested for oil products and more natural fertilizer.

These are all wonderful things to consider. It's one thing to go offgrid (I like the idea myself), but those of us that are more extreme have to have respect for guys like Dale, that simply want to bring the lessons learned to the common man. Certainly no harm can come of that. Only good things.
 
Dale Hodgins
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Marcus Harden wrote:Dale,

I'd like to know how this turns out. I don't think you should be hurt by cob traditionalists.


Actually cob traditionalists tend to be in my camp. Those who build and restore cob in Britain have generally not shunned innovation. Check out this video. http://www.youtube.com/watch?v=3a4tqRsIl10
The first 30 seconds of this video are the most interesting. The guy is using a broad hammer or slapper. It may also be a tamper. Notice the size of globs being tossed to the girl on the wall. They're not fiddling with fist sized clumps.

In traditional English cob building, the materials were mixed by penned animals and homes had a form similar to that of brick and stone houses. In the revival of this technique in Britain, homes tend to have a more conventional look and all manner of modern equipment are employed. Most work there is in preservation. One county alone contains approximately 50,000 homes made of cob. The majority are over 200 years old and a few are in the 500 yr. range. YouTube contains videos or plastering and other preservation work on these homes. I think there's more to be learned from this long housing tradition than from recent developments in other areas. Another important thing for me is that the entire scene is not dominated by certain political interests. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- This guy from Devon is using air equipment to apply a lime finish to a 500 year old wall. http://www.youtube.com/watch?v=rQOpessHuC8

This one shows his finished wall, ready to weather the next 500 years. http://www.youtube.com/watch?v=eY_KgV_uM5w

This guy is using a special tool for "harling" which is throwing material onto the wall. http://www.youtube.com/watch?v=deQDqmvnIPQ&feature=endscreen&NR=1
 
Burra Maluca
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Thanks Dale. I've embedded the video below.

 
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