New Year’s 2022; composting diapers

January 3, 2022

It’s been an indifferent winter so far, with just a day or two of snow suitable for skiing on the north side trails and a warm inter-holiday week, but a cold spell was forecast so I took advantage on the Sunday after New Year’s Day to string out the hoses and compost diapers.

Diaper consumption is gradually decreasing in preference to use of the potty, but still the compostable liners accumulate, and I have made a habit of slurrying them (yellow ones only) and mixing with diverse organic matter to make very nice compost for the garden. In the photo above, the right bin holds the last fall batch that has cooked down nicely, while I am layering and mixing fresh material on the left. I had to dig off a few inches of snow to get at the pile of leaves and garden waste behind the bins.

Building a kinematic solar chicken tractor (A Philosophy of Outbuildings, 2nd worked example)

October 27, 2021

In late 2019 I wrote a post called A Philosophy of Outbuildings, attempting to capture the lessons from 40 years of making and using utility structures on the land in Five Islands, and now a bit here in Gorham. In the summer of 2020, as part of our garden expansion I took down our oldest, smallest ground-mount PV array of four modules, which was mounted on a rack of untreated 2×4 that was rotting up from the ground. We needed a new rack for the PV, and we have also talked for a long time about eventually getting chickens here. I had already worked up a mostly-effective technique for using quality aluminum foil tape to weathershed the seams between modules on a ground-mount array, making a pretty nice garden shed that might become a third essay in this series. So a solar chickenhouse seemed like a decent idea.

One of the principles of the philosophy is that Small Outbuildings Should be Portable – because they can be, because it increases the value of the time put into building them, and because otherwise they often get in the way of bigger plans that come along later. In the case of grazing livestock, portability is a primary requirement, to expose the critters to fresh pasture, and the Chicken Tractor is at this point a classic DIY project. My parents have taken that concept to the extreme in Five Islands with two small barns for laying hens, built on the four-wheeled frames of retired haywagons from the Holbrook dairy operation in Woolwich. These are truly impressive structures, complete with large winch-up flyways, and those hens get moved every 2-3 days, but a conventional stick-frame rectangular building on a long, spindly four-wheel wagon will come under some pretty intense wracking strains when pulled over uneven ground, and indeed the first iteration ended up somewhat diagonal due to this fundamental challenge of kinematics.

The wracking of the four-wheel chicken tractors offended my engineer’s sense of propriety, much as an out-of-plumb outhouse grates on a carpenter’s, so I resolved that our portable solar chicken house would be kinematically correct, with a three-point stance to avoid wrenching when transported. This complicated things significantly, but the end result was satisfying enough to document in this post, with some lessons learned that could be useful in designing similar buildings.

The size of the building was roughly set by the four PV panels to be mounted, older 185W Chinese mono modules that measure a bit over 2×5′ each. To minimize footprint and provide a bit of standing headroom inside, I arranged them 2×2 in portrait format, leading to a collector a bit over 5’wx10’h, set at 45 degrees (we’re at 44 degrees north here), giving a right-triangular wedge for the main mass of the structure.

When tilted up, the run of the collector array fell just short of 8′. But for efficient use of materials, and to provide a bit more floorspace, I went for a full 8′ in the north-south dimension. To cover the gap at the north end I put in a small north-facing roof facet which I covered with twinwall polycarbonate to let in a bit of light; this also echoes the design of the (decidedly non-portable) solar garden shed that sits just to the north. In the end this resulted in a lot of picky carpentry; it might have been best to tilt the array slightly flatter than 45 degrees and deal with the reduced headroom, but I am happy with the result. With our without the north-facing rooflet, the north wall is the only one big enough to receive a door, and is also a convenient place to implement daylight/ventilation.

Inspired by a coop Gerry Carroll built in NJ, I was keen to try accessing the laying boxes from outside, and the building could use a bit more width to give it stance against blowing over, so I slung two rows of laying boxes on either side running north-south, designed to have hinged access hatches on the side walls and de minimis shed roofs to cover. I clad the laying box sheds with salvaged mobile-home skirting in a nice gray-brown faux woodgrain color, scored from Dave’s salvage collection. We’ll see how the external-access laying boxes work out if we ever get around to populating it with chickens.

The kinematic foundation is the most unique element of the structure, and fortunately I have some decent pictures. Because the shed would be located within our large fenced garden area, it would probably move relatively infrequently (on an annual or slower-than-annual rotation) to allow the chickens to fertilize a fallow area, so I decided to use skids rather than wheels. The kinematic principle could (and I would say should) be applied to a wheeled structure with minor variations. Like the portable tractor shed I built upriver, the skids are made of ordinary treated lumber, 4×6 flatwise in this case. Here are some shots of the substructure under construction, showing how the floor can pivot freely and be adjusted independent of the base:

Built upward from the skids are a front crossbeam (2×10, sculpted top and bottom to increase clearance) and a back crossbeam (C-channel construction of PT decking, similarly sculpted below for ground clearance), plus 2×6 diagonal braces to keep the substructure square. The front crossbeam has metal plates sandwiching it fore and aft, through-bolted (in this case the plates happen to be leftover tail vanes from a prototype wind turbine). The curved metal plates project well above the crossbeam, and form a trunnion that accepts one of the joists of the floor deck with a large pivot bolt. This gives the superstructure a roll degree of freedom relative to the substructure, which is key to preventing the building from wracking as the skids move semi-independently to conform to the surface contour of the soil. Additionally, the flex in the metal plates, the wooden joists, and general slop in the system allows sufficient pitch degree of freedom such that the floor can be leveled.

The ability to level the floor is not necessary to the fundamental goal of a kinematically appropriate structure, and the chickens probably won’t care, but as the son of a carpenter I feel that certain standards must be upheld. So the north end of the structure is supported off the rear crossbeam by two salvaged scissor screw jacks from light cars, which allows the floor attitude to be adjusted, taking advantage of the roll and (modest) pitch degrees of freedom of the front pivot point described above.

Between the solar panel roof and the specialized kinematic base, I tried hard to keep the structure from getting too heavy. The floor is 1/2″ PT plywood framed with a 2×6 perimeter, but joisted with 5/4 decking. The wall framing is similarly light, mostly decking ripped in half lengthwise, and the side walls of the structure are diagonally planked with Hammond Lumber’s thinner, nicer-grade shiplap that is rough one side but measures an actual 3/4″ thick (where regular shiplap is actual 7/8″ thick). I also incorporated some hardware cloth and twinwall polycarbonate for light and ventilation. Here are some photos of construction:

We got an early snow in the fall of 2020 that then melted, and I took the opportunity to skid it into the garden to its final (for now) home:

The structure moved nicely, and it was almost a letdown how trivial it was to level it in place with a couple cranks of the screw jacks. Because the superstructure is intentionally built light, it is secured downward to the skids and the jacks with light chain and preloaded by turnbuckles left over from a fencing project. I bolted on the PV modules, and it sat through the winter and spring while other projects took priority, including growing and harvesting a nice crop of rye (which deserves a post of its own):

I finally got to ‘finishing’ it, roofing the laying box sheds with the trailer skirting and building a door on the north wall this summer. All in all, a satisfying project, currently storing gardening sundries and awaiting a shipment of chicks someday.

Naturally in the course of this type of exploratory project, I came up with some things I’d do differently next time. Most basically, the construction makes the superstructure a few inches taller than I think is necessary, and fitting the kinematic degrees of freedom into a shallower package would be cool. This might be accomplished by dispensing with the metal trunnion plates and fitting the front crossbeam between two closely-spaced floor joists. This would also require a more compact arrangement for the adjustable elevation on the north end, and while the scissor screw jacks were free from Dave’s dump collection and well-suited, they have a temporary, inelegant feel about them; in building another one I might try to substitute some stumpy homemade turnbuckles with welded end plates, fabricated from a couple large-diameter left-hand threaded nuts and bolts. This would obviously also provide downforce, eliminating the need for the turnbuckle/chain.

Reflections on another year of serious gardening (2021)

October 4, 2021

A post to capture findings from another year of trying to do a good job in the vegetable garden (last year’s post).

The weather was odd; spring seemed ordinary, then June was absurdly dry, then July was ridiculously wet right into August. then things seemed to even out, but I can’t remember a late summer period that seemed this green. We irrigated steadily early in the year, but never once after it started to rain in July.

Made an effort to drive up fertility with good effect; got the usual 3 yards of surf-and-turf in the spring from O’Donal’s, and probably made and spread nearly that much of our own compost.

Weed control was OK through most of the summer thanks to the hacked BMX-bike wheelhoe and a spiffy collinear hoe I bought from Johnny’s. Got sloppier late in the year as things turned rampant and other projects intervened.

Fencing is in good shape, thanks to big investment last year. No woodchucks in the squash this time; deer only got in when we left the gate open.

By crop:

  • Brassicas: did pretty well in general; planted all in one row and sprayed 2 gallons of BT (organic-listed bacterium that parasitizes moth larvae) on the row 3, maybe 4 times over the course of the summer, which made a major difference – e.g. the Brussels sprout tops were getting skeletonized and recovered immediately right after I sprayed.
    • Broccoli: direct-seeded 2-3 fedco varieties, one or two failed so got a dozen starts from O’Donals. Couldn’t tell the difference between varieties; froze several gallon bags’ worth on cookie sheets, since we always use a lot. Kept producing off side shoots well into the fall.
    • Kohlrabi – grew for the first time after being inspired by a picture of Holly’s son with a huge one. His description was pretty accurate – like a giant hunk of broccoli stem. The root is functionally similar to jicama but a bit zippy instead of sweet, and makes pleasant fresh eating as a low-cal snack, or grated into a salad; I blanched and froze a few quarts to try in soup. Surprisingly good stir-fried with sesame oil and salt, per HG advice. Next year: attempt to succession-plant; start some late for fall.
    • Purple cabbage – I direct-seeded this early, and thinned/transplanted in the rows. They did well, but ripened while there was a ton of more compelling food in the garden. Plant late for fall/storage
    • Kale: didn’t plant kale early, and didn’t miss it much. Planted some late which is doing well now; seems like the right move. get some other varieties next year besides Russian
    • Brussels sprouts: still coming along – look pretty good.
  • Cucurbits – very satisfactory this year. We experimented training cucurbits and tomatoes on the garden perimeter fence; the tomatoes did great but the squash got munched by deer – so in the future we should either string electric fence outboard or confine the squash to the interior of the garden.
    • For summer squash I started some early in the greenhouse in 4″ pots – Yellow crooknecks, the same anonymous green pattypans I bought in the spring of 2020 at O’Donal’s, and a green zucchini variety I bought from fedco without reading the description very carefully. These latter turned out to be zucchini rampicante, which are in the moschata family, and they worked really well – resistant to the bugs that eat the stems of other squash, long-lived, and prolific. They would have been even more impressive if the deer hadn’t decimated them where they climbed the fence, and if I hadn’t planted them over mowed red clover that came up pretty think and competed for light. The pattypans were OK but nothing like last year (maybe try a different variety next year), and the yellow squash faded fast but I planted a succession probably around July 4 that did well (and is still fruiting in late Sept, while just starting to get mildewed).
    • Cucumbers likewise we planted along the perimeter fence (as well as in the greenhouse). The deer got them, but still got plenty for salad and sandwiches (not sure if Kelsey pickled; I think we’ve had more in past years…) – Plant fewer next year, and succession-plant them
    • I grew a few pots of honeydew, cantaloupe, and watermelon. Got a few of each that were pretty good. They got a bit lost under the tomatoes that were also planted on the fence; in general I have a sense that if we committed space and babied them, we could grow some serious melons.
    • For winter squash I planted 3-4 hills of waltham butternut, and got about 120lb of fruits. This grew in an area about 15×20′; this represents a pretty decent people-feeding rate of around 4.5 people per acre, although at 200 calories per pound it would be tough to live on butternut squash…
  • Tomatoes: did OK, planted mostly along the perimeter fence, and the deer didn’t touch them. Didn’t pay enough attention to varieties, and ended up with a bunch of sungold and small red cherries, and not so many large eating/canning tomatoes. The elongated red cherries were pretty nice for fresh eating, and overall we got plenty of fruit – I canned over 6 gallons of diced tomatoes in enriched sauce made by reducing mass quantities of the little ones in a crockpot and running them through Kelsey’s squeezo. The ones in the greenhouse did OK but actually came in later than the outdoor plants; the greenhouse seems less necessary for them than for peppers and eggplants. Plant more large ones next year.
  • Basil: planted around 12 row-feet in the greenhouse, and similar outdoors. Both did great, made several ~quart batches of pesto and froze in ice cube trays. The outdoor planting started to brown pretty early in September; it definitely seems to be among the most sensitive to cold of the stuff we grow.
  • Eggplants: did great in the greenhouse. Didn’t bother outdoors based on last year
  • Peppers: bought some starts at O’Donal’s, mostly planted in the greenhouse where they did OK. Two plants outdoors kinda fizzled; not clear why
  • Carrots: did a good job of planting successions, mostly of Yaya. Frustrating since the cutworms really like them, but still got plenty. Carrots seem happy in our soil; I definitely see the potential to grow an absurd amount by refining practices. Mark Fulford has done some experiments with intense organic cultivation of carrots that seem pretty impressive, yielding 54-65,000lb/acre in 70 days – equivalent to a feeding power of approximately 15 people/acre.
  • Beets: got a couple meals from an early planting, but goldfinches have taken a liking to them and skeletonize the leaves (likewise of chard). Plant small successions of beets under floating row cover next year.
  • Chard: Grew some; goldfinches ate most of it. Kelsey feeds it to her family and they seem to like it. One of those things where by the time it’s ready to eat, there are a lot of other tasty things to eat.
  • Spinach: overwintered some and it was great to have in the spring. Got a good long row planted early, and ate heavily of it (plus froze some) despite heavy predation by cutworms. Later plantings bolted in the heat; Kelsey got in another good long row for fall that’s doing well.
  • Alliums: not a fantastic year. I planted some yellow onion sets, and they got heavily munched by cutworms; the ones that made it looked good but started to rot quickly after harvest. Kelsey transplanted a small patch from seed that seemed to do better though they also got cutwormed. Maybe BT spray would help. We also planted leeks that she started from seed; it too got cutworms and struggled to get going. Definitely not as good as last year.
  • Green beans: Kelsey planted a couple rows and they kept going all summer – seems like they liked the rainy weather.
  • Peas: snap peas did OK as usual – great fresh eating right in the garden; I haven’t figured a way to freeze them that’s actually tasty. Also grew a couple types of shell peas, but they are a lot of work – seems marginal for to grow and shell them for storage. I did look online and it appears that one can make a homemade tumbler out of wood and hardware cloth to shell them automatically.
  • Potatoes: did fine; crop seemed not-especially-heavy but quality was good. Picked a lot of beetles, plus one whack of spinosad when the picking got behind.

Topo vs. Graph

May 7, 2021

As a kid, I got my introduction to hiking in a particularly spectacular setting, the Wind River mountains of Wyoming. As soon as my sister and I were old enough, my parents would prepare us with local hikes, and drive us west in a marathon road trip – sometimes straight through, sometimes with a night in a motel in Grand Island, Nebraska – and we’d disappear into the wilderness.

In most peoples’ imagination, trails are an integral part of hiking. But one striking thing about the western mountains is that above a magical elevation, trees thin out and trails became optional. We could pick a particularly remote and interesting-looking spot and just go directly there, navigating through the landscape visually, with greater or looser precision as dictated by the terrain and our haste or leisure. The glacier-scoured contours of those mountains seem custom-configured to encourage this sort of loose-jointed bushwhacking or aimful wandering, with open glades, bold ridges, and frequent grassy benches to offer a path down even quite steep slopes.

I didn’t fully appreciate the freedom of travel and freedom of thought that this sort of terrain encourages until much later, when I started hiking and backpacking in the White Mountains as an escape from city life in college. Hiking in the east is all about trails. Off-trail travel in the eastern mountains is difficult to impossible given the heavy growth of trees and underbrush – and unethical above treeline, given the fragile soil and heavy traffic. Views are limited, and navigation is a matter of keeping track of which trail you are on and not missing the junctions. When the rigidity of trails is combined with infrequent vistas, humidity, crowds, and restricted camping locations, the overall comparison isn’t favorable.

I think these two modes of navigation are actually quite general. The first, western version I’ll call Topo, after the special color-printed topographical maps that we would order in preparation for those Rocky Mountain trips. A topo map offers comprehensive, uniform fine-grained knowledge of the entire landscape, down to the resolution of the contour interval and scale. A Topo landscape facilitates broad freedom of travel (albeit with natural obstacles and salients), and trails are of secondary importance or non-existent. The eastern version might uncharitably be called ‘Maze’ but more neutrally I’ll call it Graph, since in a mathematical sense that’s basically what the AMC’s hiking maps are, with thick lines representing trails and segment mileage printed on, the scale relatively broad and the contour lines recessive. The idea of Graph is that getting from place to place is less about the details of the landscape, and more about the paths through it (which are discrete and relatively few), the quality of those paths, and the logic of linkages among them.

These two ways of thinking about a landscape don’t depend on holding a map of one type or other. The broad meaning of Topo is to have an actual overall layout in your head at some fidelity, and a sense of your physical position on it to some accuracy. I came to appreciate it in the wilderness, but it’s just as useful in cities: ‘I’ll just head south until it gets kind of downtown-ish, then go east until I hit the river.’ Graph means discrete knowledge that you’re on trail X between point A and point B, combined with a finite list of instructions for getting certain places: ‘go out the door, you’re on Prospect St. Turn left, then walk until you hit Mass Ave. Take another left and walk to #77.’

Some landscapes (open, legible) lend themselves to Topo, while others (cluttered, opaque) lend themselves to Graph. A train on a railroad is the ultimate Graph – there are only so many tracks, and you are either on a track or you are in very bad shape. The ultimate Topo is the sky for a bird, or perhaps the ocean for a fish, though given a chart and GPS the ocean is Topo for a boat. With their orderly grids, some cities encourage Topo-type facility (e.g. Salt Lake), while in others (Boston) perhaps only particularly-talented natives eventually achieve Topo, and everyone else operates in Graph. When I first moved to Portland, the cluster of roads around PWM was an impenetrable tangle in my mind, and I had the barest Graph-based proficiency in how to get to a few places. As time has passed I am gradually approaching an overall Topo sense of the layout, and a facility with back-streets and connections.

I believe that the ideas of Graph and Topo extend usefully to the contours of landscapes that are not geographical. Topo is broad confidence, legibility, and freedom to ramble through the terrain of the solution space. Graph is narrow efficiency, stick-to-known-paths, and so tends fragile. Speaking of fragile, in my amateur attempts to learn and play fiddle tunes, I am almost purely Graph – the line of the melody might as well be a railroad track. If I am lucky, my mind and fingers can stay on the rails and keep the tempo. If I fall off the track I must back up, retrace my steps, and attempt to navigate the junctions until I make it correctly twice around the A part. Then the B part traverses what is dimly recognizable as the same landscape, albeit at higher or lower altitude – the exact relationship between the two is obscured by dense thickets of wrong notes. But it’s obvious that talented musicians navigate the same musical landscape in Topo. They see not just the single set track of the melody but rather the entire terrain of chords and harmony, and while they follow the cycles by instinct, they can just as easily jump the rails and ramble freely over the entire glorious landscape – and even take flight, to improvise and soar ecstatically like an acrobatic bird, then land back on the rails without missing a beat.

The same modes of thought apply in engineering realms as well. When I was a kid I had one of those Radio Shack ‘200-in-one’ electronics project kits with the little springs and jumper wires for making connections, and to me the projects were literally Graph – use wires to make connections following a sequence of numbers, then throw the switch and see if it works. While the manual also had narrative descriptions of how each circuit functioned, maddeningly they were written at a level suitable for a competent analog electrical engineer, not an elementary school kid. So my knowledge remained Graph, and in analog electronics I never got much beyond that, while the best engineers I know operate in pure and glorious Topo, flipping effortlessly between digital and analog, frequency and time domain, with a gut feel for every nonlinearity of a magnetic core or an insulated gate semiconductor. If only those old kits shipped with a copy of The Art of Electronics, I might not be a mechanical engineer.

Being invisible and mostly insensible, electricity is by nature hard to grasp, but chemistry is probably worse. My knowledge of aluminum alloys is strictly Graph: ‘Use 6061 for structural, 6063 for cosmetic. Use 7075 for airplanes.’ But I am sure that a skilled metallurgist has Topo knowledge of aluminum alloys – understands intuitively what the copper, zinc, silicon, etc. are doing in there, and I bet in a pinch they could whip up something pretty good in a crucible the way a skilled cook improvises in the kitchen. Chemistry might be where Topo knowledge is most impressive – while mortals scan an impenetrable text for clues and pray that nothing explodes, like Harry Potter on the first day of Potions class, the master seems to have an intuitive feel for what molecules want.

Cooking is domestic chemistry, and in the kitchen some people are strictly Graph, and wouldn’t dare make something without a recipe, while others are casually Topo, adding a dash of this and a sprinkle of that. I fall somewhere in between – when making soup or yeast bread I operate in Topo, while in quickbreads I’m more cautious and hew close to a recipe (Graph). To me the distinction feels inherent in the landscape/solution space of those foods, but perhaps there are others who see them oppositely?

While I’m firmly Graph in music, analog electronics, chemistry, and countless other areas (literature, small engine repair), and transitional in cooking, I enjoy solid Topo facility when working with wood, metal, and manufacturing technologies. I’ve got pretty good familiarity with rough and finish carpentry and working knowledge of many adjacent trades, and can play with the techniques to solve unique problems. I know what most ordinary kinds of wood are good for, and I can fell a tree, get out a bolt, slice it up with a bandsaw, dry it, join, plane, saw, assemble, and finish, and make something nice out of it. In metal I can MIG, TIG, stick, solder, and braze, and could mill and turn with decent precision when I was in practice. In manufacturing I know how most things are made and why they’re made that way, and can mix and match to come up with something new. Alex Slocum who taught the famous 2.70/2.007 design class used the metaphor of Legos – each material, technique, structure, or mechanism you learn is like having another Lego piece in your toy box. The more pieces you collect, the more freedom you have to solve problems efficiently, and once you collect enough, you transition from ‘I know A way to solve this problem’ (Graph) to ‘Which of the Many ways to solve this problem do I feel like using in this instance?’ (Topo)

Skill in prediction seems central to having a Topo understanding of a landscape: “There will likely be an annoying boulder field under that cliff face.” “If the screws are too short they are likely to pull out of the end grain.” Professor Slocum also talked usefully of having a ‘Mental FEA Module’ – a good engineer should work to build, exercise, and test their intuition for predicting how their designs will behave, so they can mentally iterate through potential solutions, rather than ‘guessing and checking’ experimentally or relying heavily on closed-form math or computer simulation. A big box of mental design Legos is like a good topo map, providing fine-grained coverage of the landscape, and a well-tuned Mental FEA module provides advance judgment about what parts of that landscape will make for easy walking. Design then starts as a playful mental exercise of trying to sense what physics will work well, what reality is struggling to communicate to us – in the words of the Indigo Girls, ‘trying to feel what’s coming next’.

Beyond any one person’s knowledge, I have the sense that the human scientific project started off groping in darkness with the barest fragments of Graph knowledge and has rapidly built out an ever-more-detailed Topo map of big chunks of reality. The alchemists could see very little of the landscape of Chemistry, and fumbled around hoping to find One Weird Trick for turning dross into gold; now the physicist Sean Carroll has provocatively claimed that the laws of physics underlying everyday phenomena are completely explained. That’s not to say we understand emergent phenomena, or the Big Bang or dark matter, but rather that essentially there are no blank spaces on the Topo map of forces and particles that make up our everyday lives. Fortunately or unfortunately, that still leaves plenty of work to do – e.g. Prevent Pandemics. Cure Cancer. Build a Sustainable Global Economy.

A philosophy of outbuildings: first worked example

April 20, 2021

In late 2019 I wrote a post called A Philosophy of Outbuildings, attempting to capture the lessons from 40 years of making and using utility structures ranging from outhouses to the awesome barn my parents built that we’ve been making cider in. One of the fundamental principles was that small outbuildings should be portable, so they can be moved to a more useful spot (or to get them out of the way of some other project). Since then I’ve built a couple examples of this, and thought I’d capture the results in case they are of any use to the greater internet community.

The purpose of the first was simple: to shelter a small diesel tractor that came to us from Five Islands. The tractor gets used for bushhogging, harvesting firewood, and moving mulch/gravel around the yard, and sits idle through the winter; it is approximately as old as I am and would deteriorate rapidly if left in the sun/rain, so it needed some protection. My model was the very successful open-front pole-barn that my father and grandfather built in the early 1980s that we used to keep the cider operation out of the rain in Cider Year Five, but I didn’t have firm plans for the land where I built it, so I wanted to be able to move the shed later if I needed to.

Expanding slightly on the dimensions of a single bay of that pole barn, I settled on a footprint 10′ wide and 14′ long, with about four feet of overhang on the open west end. The building would be floorless, open on one end, and sit on two 16′ 6×6 PT skids with chamfered ends, blocked up level on pads of coarse crushed stone. The closed back end of the building is built on a 4×4 cross-beam set on top of the skids and lagged down. The walls are framed with rough-sawed 2x4s from Five Islands, and diagonally sheathed with Hammond Lumber shiplap. I used a chevron pattern for the sheathing on the side walls, in hopes of providing the long 6×6 skids some structural support to prevent sagging. I did the project in a hurry with the winter of 2019-2020 closing in, so I don’t have great construction pictures; here’s the walls framed up at the end of the first long day:

Rafters were cut from 2x6x8′ rough-sawn, with something like a 6-pitch. Collars were likewise 2×6; 2×4 would do but I had thoughts of hanging a boat from them. The roof is strapped with 1x and dried in with dark green five-rib steel sheet. The overhang on the open end is supported by 4×4 diagonal braces, and the roof structure is tied together by a 20′ PT 2×8 ridgebeam. It got dark inside, so I used a large piece of salvaged plexiglass on the closed gable end up high to let in a bit of light. Here’s the ‘finished’ shed, with happy tractor inside:

The most obvious miss was that I should have extended the diagonal siding to tie in with the 4×4 brace poles that hold up the overhang; this was not obvious because I built the wall sections before fully thinking through the overhangs, but it would have made the structure stouter and also helped to keep weather out. The gable end of the overhang could also be sheathed to keep rain/leaves out, at the cost of some light.

At least until I further perfect the art of portable buildings, this was as large as I was prepared to go on a floorless open structure that I would hope to move with come-a-longs, pulleys, and small tractors/vehicles. My biggest concern was wracking/distortion, both from natural ground settling and also during any future move. To prevent in-plane wracking of the open end I added a pair of a-frame type diagonal braces that can be seen in the photo above, to tie the side walls and end collar tie to the ridgebeam; not sure how well they will work, but they look cool. There is also some small chance of a tornado or derecho-type event picking it up and blowing it over; it’s surrounded by mature trees so it feels fairly protected, but at some point when I put the last few boards on the gable end I should probably also cable it down to the bases of a couple trees for extra security.

In order to skid the building I would plan to temporarily add structure to tie together the skids at the open end, and also temporary internal cross-bracing or cabling to keep the footprint square. With just 5″ of undercarriage clearance, it would be interesting to see what it can skid over; I have a feeling that I should have done something to elevate the bottom of the back wall more – e.g. bandsaw an arch into the underside of a 4×8.

From an ecological perspective, other than the steel roofing (approximately 2lb/CO2 per square foot as calculated in the post linked above) and a handful of pieces of PT trucked up from the Southeast, the building is made from untreated locally milled lumber. The overhangs are decent, the skids sit on crushed stone and/or blocks, and the site is reasonably airy for being in the woods, so I am optimistic it will hold up well over time.

The next building in the series is smaller but more exotic – a kinematically-correct portable solar chicken coop.

A box of tools – then and now

April 2, 2021

At some point over the winter I stumbled onto a mention of the Mastermyr chest on the web, and marveled at the similarity of thousand-year-old Viking tools to hand tools today:

Not long after, I was puttering in the workshop with Z, who was fascinated by and kept pulling tools out of my own wooden toolbox, so I decided to pull everything out, dump the sawdust and drywall screws, and take my own version:

It appears that the Mastermyr box owner was a locksmith, and I imagine folks in that trade as being clever, thoughtful, and handy. It’s fun to imagine a Viking craftsman time-traveling into the present and wondering at 21st century tools; most I imagine they’d figure out quickly, even if they weren’t a thing back then (bubble level, chalk line, hex wrenches). The stud finder and the digital multimeter might take some explaining. Just imagine the fascination of the Mastermyr craftsman on figuring out a staple gun – or a pneumatic framing nailer!

I’ve been enjoying a trove of practical history blog posts by a classical historian named Bret Devereaux (here’s a series about iron and ironworking). In some ways technology is surprisingly stable (e.g. pliers, hammers); in others it changes very quickly. It seems that one of the blacksmith’s most time-consuming tasks back in the day was making nails, and when I was growing up a big part of carpentry was driving large galvanized nails. Then along came pneumatics and high-quality structural screws, and recently my dad has been trying to figure out what to do with hundreds of pounds of leftover nails and spikes that it may never make sense to drive.

Richard Scarry innovation – more on hydraulics

April 1, 2021

The recent Richard Scarry post gives an example of disruptive innovation that can be enjoyed by a 2-year-old. But for a professional innovator it’s interesting to think about how it happened and why it happened then.

Christensen described how hydraulics burst on the scene in the middle of the last century and quickly displaced cable-driven equipment to dominate the market for excavation equipment. But hydraulics in some form had existed for thousands of years. Beyond the obvious dams, irrigation ditches, grist-mills, and the like, according to Wikipedia the Romans had piston pumps and used them for e.g. firefighting. Pascal figured out hydrostatics in the 1600s, and a fellow named Joseph Bramah invented the hydraulic press in the late 1700s (Bramah also invented the flush toilet). In the 1900s hydraulic power distribution briefly became a thing in the UK, before being eclipsed by electricity. The famous Tower Bridge in London built in the late 1800s was hydraulic-powered (literally – the working fluid was water), and apparently that system operated into the 1970s.

Mechanical power transmitted by cables and pulleys is also thousands of years old, dating back to at least ancient Egypt. Ships made extensive use of pulleys, blocks, and tackle, to the extent that the British navy’s need for blocks led to one of the earliest forms of mechanized manufacturing. On land, the human-powered treadwheel was used to build cathedrals and other works, and presaged the digging machines that Christensen wrote about.

I haven’t dug deeply into the history of manufactured hydraulics, but I suspect that the sudden breakout of hydraulic technology in excavation has more to do with the pumps than the pistons. It stands to reason that piston-cylinder setups that can seal properly and take significant pressure would arrive at around the time as piston-based engines, based on the necessary precision of boring machines and sophistication of oil seals and the like. But in order to make practical use of hydraulics for digging machinery, you have to be able to deliver significant energy to the hydraulic cylinders, and to do it in a mobile machine (as opposed to stationary works where you can tap pressure off a dam or something) you need compact, robust, high-pressure pumps. Most of these seem to be some form of gearpump, which in turn requires precision in machining the complex meshing surfaces, an art and science that surely advanced massively in the 20th century due to automotive transmissions, aircraft, and general engine-engineering. As we have learned the hard way in pedal cider experiments, high shaft speeds are important to getting decent efficiency in hydraulic pumps and motors, given that leakage flows are driven by pressure, so engines had to speed up to a certain point, and gears had to get precise enough to allow that to happen.

By comparison, larger, cruder open-gearing systems driving drums and cables seem more compatible with older, lower-speed engines, and generally requiring of a lot less precision – not to mention that when all this was getting started, lubricating oil was harvested by hand-hunting whales on the open ocean, so it would not be attractive to use it as the working fluid for large, crude, leaky piston systems.

Putting all this together, it doesn’t seem surprising that cable-driven machinery dominated in the age of steam and early internal-combustion engines, but within a few decades after high-speed engines came of age an entire industry would spring up around compact, high-pressure hydraulic drive systems. And in the time since Christensen wrote that chapter, hydraulics have continued their run to the point where many small tractors and other light construction machinery – where smoothness and durability are more important than pure energy transmission efficiency – have no direct drive mechanisms at all. I remember first being struck when looking ‘under the hood’ of Dave’s small bobcat excavator and realizing the whole thing was run by one big pump.

The cables-to-hydraulics story is an easily-visualized and personally interesting example of a larger set of phenomena in technology and innovation, where a certain technology platform dominates for a long time, despite the presence of minor competitors, and then some other technology platform goes on a tear and displaces both the previously-dominant platform and all other competitors to become the new incumbent. It’s pretty clear to me that the key to understanding this is positive feedback, or virtuous cycles of economies of scale, cost reduction, profit, and reinvestment in innovation. I hope to write a post or two about these virtuous cycles soon, specifically on the striking recent growth in silicon solar cells and lithium batteries.

on the Texas energy catastrophe

February 21, 2021

Like most people I’ve watched the Texas power grid collapse and the resulting cascade of failures with dismay, though perhaps with less shock than is typical. The modern way of life is utterly dependent on copious and freely-flowing energy (85% of it from fossil fuels), and ordinary people take that for granted to a degree that is maddening from the perspective of an energy engineer.

This morning the New York Times has an article about people in Texas who didn’t lose their power, but are facing 5-figure monthly electric bills because of the specifics of the rate plans they signed up for in the de-regulated market. Apparently among the over 200 competitive plans in the state, some have the schtick ‘wholesale plus $10/mo’; when wholesale rates railed out at $9/kWh, those plans duly passed the cost on to the homeowners. (The average home uses about 30kWh per day; surely big Texas homes in a cold snap use much more.)

Besides falsely blaming renewables for the state’s failures, the governor is now promising to protect Texans from that market functioning as intended – from the same article:

“We have a responsibility to protect Texans from spikes in their energy bills that are a result of the severe winter weather and power outages,” Mr. Abbott, who has been reeling after the state’s infrastructure failure, said in a statement after the meeting. He added that Democrats and Republicans would work together to make sure people “do not get stuck with skyrocketing energy bills.”

I believe it was Amory Lovins of the Rocky Mountain Institute who said something to the effect that “Markets are designed to be Efficient, not Sufficient,” and this is a great example of that. The provision of affordable, reliable, non-planet-destroying energy to over 300M Americans and nearly 8B humans is not primarily an economic project, it is primarily a technological project. Economic systems are technology, markets are an extremely powerful tool to lubricate the inner workings of that project, and financial tools could be an engine of transformation (e.g. a global carbon tax), but by themselves they don’t magically solve much of anything.

The power grid is practically the textbook example of a natural monopoly, at least for transmission and distribution, and the trouble in Texas obviously started with a lot of equipment (mostly around natural gas) shutting down in conditions it wasn’t designed to run in. The modern electric grid operates essentially ‘just in time’ without significant energy storage at any step or scale. Most homes don’t have backup systems and aren’t very well insulated; pipes burst below freezing and homes flood, and from there things go to hell pretty quickly.

The wildest thing about this story is that $9 per kWh is still a bargain in human energetic terms. As I wrote in Energy Enlightenment and the better angels of our exotherm, an average human at hard labor (say pedaling to power an apple cider mill) can only produce about 1kWh per day. A human diet of 2000 dietary calories per day is only 2.3kWh, and this puts a hard ceiling on what a person eating that much could deliver on an ongoing basis. The amount of energy that typical Americans take utterly for granted is a ginormous thundering torrent in absolute human terms. If more people realized this, they might refocus some of their pandemic home improvement efforts on superinsulation, backup systems, self-generation (i.e. rooftop PV), and modest onsite energy storage – likely some combination of firewood, propane, and lithium.

The problem of ‘lifestyle’

February 8, 2021

I hate the word ‘lifestyle’, at least in relation to anything that matters, because it trivializes that which should not be trivialized. Much like Consumers, it is a word that slips in easily to replace something harder and more important.

Collectively, humans have colossal power – including the ability to defeat (or not) viral contagion and transform, devastate, or renew landscapes.  In the fossil fuel era, we have materially altered the temperature of the entire surface of the planet in a few short decades, and are creating in a century an extinction event that will be visible over the sweep of billions of years. We also have choices, and so we have responsibility for our actions.  “They” did not do these things, WE are doing them – you and I do them every time we pump gas, eat a steak, or step onto an airplane. While each person’s individual contribution is miniscule, they add up exactly to our collective impact – there is nothing else.

Engaging meaningfully with global environmental challenges requires scientific literacy and the ability to see past appearances.  Carbon dioxide in the atmosphere, mercury in fish – these things are literally invisible, and undetectable without the tools of science.  And the chains of causation between my everyday actions and my infinitessimal contribution to them are invisible likewise. One must dig under the surface to understand them.  But Lifestyle is all about appearances.  It points attention at cultural signifiers, gloss, and status, not the sinewy reality of material and energy flows and actual impacts of behavior.

At some point in college I did a quantitative accounting of my carbon footprint, and on many fronts I did well – living in a cooperative community with nearly 30 other young people, eating a vegetarian diet, riding a bicycle as my daily commuter. But I was surprised to find that well over half of my impact came from frequent car trips to the White Mountains of New Hampshire to go hiking – despite driving a relatively efficient vehicle for the time. This took me aback, and got me thinking harder about actual impacts as opposed to easy perceptions of what constituted “environmentally-aware lifestyle activities”.

Often I have lamented here when the superficial gaze of the New York Times style page lands on rural life and finds improbably clean chickens clutched against pristine leather jackets. It’s not just that this is precious and inauthentic, it is actively leading us astray.  The combination of innumeracy and a focus on style over substance is the same instinct that causes people who travel by air to concern themselves with plastic soda straws.  A ‘rural lifestyle‘ that occupies prime farmland, consumes agricultural inputs, and releases agricultural methane without actually producing agricultural goods in a low-impact way is no more sustainable than flying across oceans to go hiking.

Much is written about the influence of money in our politics, and to be sure it is malign.  Apparently the 2020 election cost $14B, which seems like a huge sum, but in the context of over 300M people it is amazingly little – only about $40 each – the average American spends far more on energy every week.  Recent violent outbursts acknowledged, the abiding reality is mundane complacency, with smokestacks and tailpipes belching all the while.  In this context, how we use our dollars day in and day out is much more impactful than our voice or our vote. 

The pandemic has made it clear that there is a large class of people who are deeply, pathologically allergic to the idea that they are responsible for the effects their actions have on others.  But responsible they are, and responsible we are, the childish tantrums of adults notwithstanding.  Whether it’s invisible viruses spreading in close-packed rooms or ten-cylinder engines roaring freedom on a wide-open highway, we are bound together in the fabric of a reality much deeper than the gloss of fashion or the ring of tinny internet rhetoric. But “Lifestyle” says it’s all good – just a matter of freedom and fashion or personal taste.  Will it be “My lifestyle is to minimize air travel and grow vegetables”? Well then, good on you!  Or how about “My lifestyle is to jet-set around the world hunting endangered species”  Well then, good on you! If how we behave is just a matter of personal style and preference, these choices are equivalent.

These choices are not equivalent.  I believe we have a moral obligation to act as if our actions matter, and life should be about far more than style.  I want people to learn about the physical, quantitative effects of our choices, reflect on them, and change our lives so we have less negative impact on the planet, and more positive impact on our communities.  In doing this, and in keeping with the great coming together that is needed in the wake of the past few years, I hope we can pay less attention to “Lifestyle” and more to the actual gallons and miles and gigatons of reality.

The Innovator’s Dilemma: evidence from Richard Scarry

February 7, 2021

The Innovator’s Dilemma by Clayton Christensen is a classic of innovation literature. I was introduced to the basic ideas by Ely Sachs, inventor of one of the major types of 3D printing as well as two impressive kerfless silicon wafer manufacturing technologies, and I finally read it a year or two ago. A major theme is that established dominant market players are good at ‘sustaining innovation’ to incrementally improve their products in service to existing customers, but are lousy at ‘disruptive innovation’, applying new technologies to adjacent, emerging market segments. More typically a new technology is incubated by startups in adjacent markets until it matures to the point where it (and the startups pioneering it) rapidly crush and replace the older technology.

The meaty academic example he uses in the book is the hard drive industry, but chapter 3 gives much more tactile and approachable example, that of mechanical excavators. As the story goes, in the steam era an impressive industry grew up to produce cable-operated, forward-scooping excavation machines (‘steam shovels’) to serve the construction industry, and the leaders in this industry successfully navigated the transition from steam to gasoline to diesel-electric drives in the period from the mid-1800’s through 1950. Then, between the 1950s and 1970s they were suddenly crushed by the rapid emergence of new companies building hydraulic-actuated equipment. Hydraulics established itself in the niche of small, maneuverable tractor-based digging machines used by building contractors to do utility hookup work in the massive post-war building boom, and then quickly scaled up, switched to track-based drives, and grew to all but eliminate cable-driven shovels at the large end of the market. I remember as a kid seeing old rusting cable-driven shovels scattered around, and I remember in the early 1980’s that the cellar hole for my grandparents’ house was dug by a local guy with a yellow backhoe, and I remember tracked hydraulic excavators gradually becoming an everyday thing, but I never put it all together as an example of disruptive innovation.

One of the neat things about my mother being a kids’ book author is that she has an infinite collection of old picture books, and Z has been the beneficiary of that. One of his favorites is Richard Scarry’s Best Word Book Ever, originally published in 1963. There’s not much electronics in it (he wouldn’t recognize the television set even if we had one, and we haven’t bothered to teach him what the telephones are), and the cars look a bit funny with tailfins and the like, but otherwise it’s surprisingly mostly relevant. So in light of the excavation example in Christensen’s book, I was interested to see how different things are on the ‘Work Machines’ page, showing construction equipment:

The cable-driven ‘shovel’ is the most prominent piece of equipment in the lower left. There is only one machine that’s clearly hydraulic, the clunky-looking yellow ‘tractor shovel’ in the upper right. The apparently chain-driven mobile ‘bucket loader’ on the right is a piece of equipment I’m not familiar with at all, and it’s not clear how the ‘tractor scraper’ at upper right is actuated. The most interesting thing to me is the bulldozer in the upper left, whose blade appears to be raised by a cable-pulley arrangement rather than by hydraulics. I can dimly remember from when I was a kid that bulldozers often had cable winches on the back, but I never put the pieces together that originally the winch would have been used to raise the blade, and when I asked my dad confirmed that this was indeed the norm back in the day. Having done a moderate amount of earthwork using small equipment, I can imagine how the inability to apply down-pressure using the blade would be a major limitation in the usefulness of a bulldozer, so hydraulics must have been a revelation when they came along.

According to wikipedia, the Fresno scraper was invented in 1883, and it was a major innovation – for millenia the state of the art had been picks, shovels, wheelbarrows, and carts, but in the fevered pace of the industrial era the Fresno quickly evolved into the tractor scraper, dozer, and other modern equipment. When I was a kid my grandparents had a small yellow John Deere bulldozer; it was kind of a joke that it belonged to my grandmother, because my grandfather got it for (himself for) her birthday. They used it for clearing and firewood-harvesting around the land, and it was generally underpowered and marginal for our needs. The blade angle was manual, and by the time I was old enough to run it one of the steering brakes had stopped working, so it was like one of those old cheap RC cars where the way to go left was to go backwards and turn. But the blade raise/lower was at least hydraulic, and on contemplating this history I have a new appreciation for it. It’s remarkable how much even a mundane-seeming area of technology can improve in a fraction of a lifetime!