Spencer Miles

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since Feb 02, 2018
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Recent posts by Spencer Miles

I am aware that this topic is quite old, however such is the philosophy of permaculture - older is better... (replacing the latex protection on a fir-toothpick house every 5-10 years is hardly sustainable no?)

In this paper, pay special attention to page 10: https://www.cedengineering.com/userfiles/Use%20of%20Whole%20Tires%20in%20Earth%20Retaining%20Structures.pdf

This paper is quite obvious, but adds in a polypropylene rope tie, and is a whole mat structure rather than a facia wall: https://www.cedengineering.com/userfiles/Use%20of%20Whole%20Tires%20in%20Earth%20Retaining%20Structures.pdf

I recently completed construction of a device to cut the sidewall quickly - it consists of a large caster and several roller-blade wheels welded to some scrap steel - this hangs the tire in such a manner that it will spin freely in a relatively controlled rotation. There is then the Harbor Freight 6amp 1/2" drill attached to a hinge assembly via the side handle tapped holes. The drill drives a 12mm (~1/2") steel shaft supported in pillow-block-bearings. On the shaft, I attached a small motorcycle drive sprocket.

The tire is placed on the rack, and the drill is hinged down such that the drive sprocket pinches the tread between it and the large caster. Driving the drill then causes the tire to rotate. There is then a "carpet-knife blade" attached to a hinge, such that it pivots into the sidewall to be cut. It works great, and is my take on some youtube variations of tire-cutters.

I have noticed that the tire becomes a bit more wonky with one side-wall removed however, this is not a problem. The strength of a rammed-earth structure is the inherent compression strength of the fill material - the idea of the tire, or earthbag, or other wire/fabric is to provide confining pressure so as to prevent fracture planes from propagating - this whole philosophy is the concept of Mechanically Stabilized Earth (MSE), the concepts remain the same regardless of the specific mechanical material used. The somewhat wonky tire, when properly compacted, retains its round shape on account of the outward pressure of the fill. The lateral loading is well-handled by wall-system design (geogrid, tire connections, leveling, drainage, etc...) and is not strictly dependent upon the tire remaining whole.

Removing one sidewall to facilitate fill and compaction is quite ideal, and is demonstrated in the above two papers - you CAN use these papers to help convince an engineer if such is required for permitting.

For my own, my system makes use of the cut tire and 20ga chicken wire as a mechanical stabilizer/slope tie-back. I recognize that polypropylene or polyester mesh would be superior to chicken wire as my geogrid reinforcement however, cost is such an issue that it is either the wire, or a lot of prayers :(

With sufficient effort to level and compact the tire, and using the rope-ties outlined in the second paper, in addition to use of the cut sidewalls as further slope-ties and giving the wall a pyramidal-cross-section (bottom course is 4 tires deep, then three, then two, then one... again like the second paper) I see no reason why I should have any trouble.

My fill is decomposed hornblende-gneiss mineral soil (no organics) that holds a dry angle of repose of around 75 degrees - under magnification, it is very coarse/sharp, and when wet then compacted into a test-puc, it makes a very suitable solid mass.

Ultimately, I have no fear that this system (over 9 feet tall, and around 50 feet long) will be able to handle a concrete-truck driving on the area that it makes flat on my 30degree mountain slope.

Actually, using geogrid has a weird effect of becoming stronger under heavy load (crushes fill harder into the grid, making it more resistant to movement)
  -----this is why nearly every earth-work in the US Interstate system is MSE.

So, for all that info -

YES, you can most certainly cut the sidewall of the tire for your GH walls, and more than this - YOU SHOULD - it dramatically reduces the time and labor, and there is no appreciable sacrifice in finished wall performance - if it can hold a concrete truck on a mountain, it will laugh at the piddly loading experienced by a GH or earthship.

Have a good day.

(P.S., this post is the result of a few months of research into the OP's question, because I had the same one.)
5 months ago

Chris Kott wrote:Brilliant.

If something needs to be Rube Goldbergy for it to be cheap to construct and operate, so be it. It well may be that it only appears to be so, and that the complexity actually is necessary.

I think that drawing water from low-humidity air is one of the best foci for grid-independent sustainable energy sources. If that can be accomplished, it would be possible to have drip irrigation for individual trees, or lines of trees, for establishment in areas that will sustain them once established, and which will be slowly humidified and greened as a result.

I think that the ability of some solar panel setups to produce drinking water as a byproduct of electricity production is brilliant, too, and if that were coupled with intensive pasture upgrading and rotational grazing, even the harshest conditions could be made, well, pastoral, due to the added water and shade from the panels, and grazing between and underneath increasing the nutrient cycling and soil generation.

Incidentally, I would envision the cool, dry air doing really well in a cool dehydrator. You're already talking about it being a low-humidity environment. A cold dessicator that preserves heat-sensitive compounds in fruit, veggies, and herbs might be really useful.

Spencer, this type of innovation is critical, in my opinion. Please keep us posted. Good work, and good luck.


I very much appreciate your words. Not to be too -- existential -- my particular brand of scholarship has not really precipitated much in the way of encouragement: normally half-hearted derision.

By way of addressing the points you have raised, I have done preliminary work in the use of a solid desiccant (granulated calco-silica-carbon) placed in an evacuated solar tube. I would then use an RV venturi vent (they're neat - the vent can rotate into the wind, and the wind blowing through creates vacuum within the black-water tank vent line) as a means of creating a draft through the system with ambient wind. The venturi ideally draws atmosphere through the desiccant so as to saturate it. When the sun rises (humidity is highest just before sunrise) the solar tube then heats precipitating two reactions: the chamber temperature activates a "wax-motor" valve (paraffin based thermostatic valve like the one in your car, but different temperature) and this valve closes the intake of the atmosphere and creates a minor pressure drop in the system should the wind continue. The second reaction is the desorption of the water from the desiccant.

The atmosphere ducting leading to the venturi passes through an earth-cooled condenser coil with a catch basin. The minor pressure drop created by the venturi working against the closed valve slightly lowers the desorption temperature of the desiccant and thusly the "air" produced during the desorption cycle is much more humid - until the desiccant is dried out and ready for the next adsorption cycle.

The net result of this system is a rather simplified device that operates directly on ambient wind and solar energy, without any conversion losses (no electricity), one single moving part (paraffin wax expanding as it heats, contracting as it cools), and provides small amounts of pure water dependent upon ambient humidity.

It's a glass and plastic thing, say 8 feet tall and 3 inches wide - and the best part? I would like to stick it right in a raised bed planter. It's job is to make a little moist zone around the roots of the plant. Yeah - a true "Self-Watering" planter.

Additionally, my work in the wet-desiccant system leads me to believe that the working fluid may serve double duty as the electrolyte in a rechargeable chloride battery. In this scheme, it would be a wind/solar recharged battery that happens to produce water as a byproduct. That one gets me really excited as, frankly, the materials involved, while not inert, are totally within the capability of nature to handle without any trouble at all - they're actually nutrients after a single bio-process. Carbon, manganese, calcium, and chlorine.

So, what is stopping me?? What slows my work?

I fund my research with my Visa card and, not to be too whiny: it is precarious and slow.

End of the day, if you're inclined I could very much use assistance in getting parts.

The water-systems, and the adjunct battery cell are within the class of work that I have decided I will not patent. I have no trouble sharing the theory and design and, when I have completed a functional apparatus, I will publish it for public consumption. Free to any manufacturer or DIYer who wants.

Maybe I can build and sell some, but the design itself is too  important for me to hide with IP protections.

Have you any way (social media, Patreon, etc...) to help??

My website is www DOT TributaryHouse DOT com.

1 year ago

Lukas Rohrbach wrote:Hi Spencer
How did it turn out? How much water are you getting at which humidity?

Have run into tiny troubles - so I have no way to answer your question yet. With CaCl2 (calcium chloride - road salt) as the desiccant, it should do quite well.

I recently ran into a paper discussing the use of activated carbon/ calcium chloride/ silica gel composite desiccant that seems a bit more promising. The desorption temperature is much lower (70C) and it adsorbs more.

Long story short, the story isn't done yet. Sorry
1 year ago

Burl Smith wrote:If that doesn't cut the mustard he might try a Fog Catcher

Fog catch is in the works - it's down the list a bit.
1 year ago
Some thoughtful responses, I will consider the rebuttals to my position - seeing as that is what one does in a debate: consider rebuttals.

Even though I hardly find it to be "nice".
It is very true that some artifacts are found by archeologists...

under very specific circumstances - that are not so common as to constitute the rule.

Knowing this difference is part of responsible work.
1 year ago
Using a shovel results in blisters.

Moving rocks results in sore muscles.

Raising livestock requires heartbreak.

Growth and improvement are inherently uncomfortable experiences.

While balance asks most certainly to add compassion and understanding,
shielding someone from a response to patently false claims, because it might "hurt their feelings" is at best short-sighted. I said "a bit confused" instead of "indefensibly negligent in an arrogant and baseless caution extending from a position of ignorance."

I was being nice.

"Nice" has never produced any growth - it perpetuates stagnation, it enforces mediocrity.

That does not equate to rough-shod be mean - but it does cast serious doubt on "don't hurt anyone's feelings..."

Since when has learning anything been a comfortable experience? Anyone who attempts to shield me from discomfort doesn't want me to improve.

Sometimes, the moderation moolelages that I get are quite frankly infantilizing.

Everything is offensive to someone. Protectionism is exponential and self-perpetuating.

I expect my equals to point out my short-comings, I show respect by offering the same.

Trying to protect people from that... is supremely disrespectful. It is a claim that I am too fragile to learn.

I like the site, I like some of the moderators.

Treating us like we're too fragile or juvenile to cope with the reality of seeing our own mistakes....

That ain't permaculture.