2022-05-30 7 min read


Notes, 2022-05-30.

A few months ago I came to a rather radical realization: I want to sell a fractional ownership – around 50% – of my tools.

There’s a lot to be said about this. Many of these tools are things I bought two decades ago; they represent deeply meaningful phases of my life and career. When I look at them, I can remember where I’ve used them, and what I’ve used them on, and the technical – and personal – challenges I faced at the time. In many cases they have come to symbolize distinct and salient values to me: as with my sharpening equipment, with its sense of ascetic devotion; as with an old circular saw, which I believe was the first professional tool that I owned; as with all of the industrial-grade overhead extension cords and power strips that you would never really think about but which make a workshop *so* much nicer to use.

It’s jarring to contemplate these things being partially owned by someone else. It feels like I might lose the values and memories and utility that they now embody. But at the same time I recognize that New York is one of the more difficult places to establish good workshop access for oneself, and I really want to have good workshop access for myself, and it seems highly likely that I’ll continue to want good workshop access in New York City for as long as I live. And I’m just not sure if I can do that alone.

Who knows where it’ll go; wish me luck? Or, if any of this resonates with you, do be in touch ;)

-Spencer Wright

The most clicked link from last week's issue (~8% of opens) was a plea for a dumb car. Inspired partially by Kane's 2022-04-25 issue, folks in the #cities-sfba channel in the Members' Slack have banded together to share tools via a Members-only directory. And on 2022-06-13, we're doing a giveaway for Members! We'll be giving away one Watchy, an open source e-paper wristwatch complete with a CNC'd aluminum case. Join today and head over to the #tools channel for details!

Planning & Strategy.

  • The HEATR act, currently in the US Senate Finance committee, would provide a tax credit of up to $1000 for each heat pump installed. This is a *fantastic* idea. Even without tax credits, the efficiency (and therefore the economics) of heat pumps are a win-win-win over their fossil fuel and resistive counterparts, and eventually we’ll all clamor over each other to warm our homes and showers with them. The question is, how much fossil fuel (and money) do you want to burn before you make the switch?

    Related: It might have seemed absurd at the time, but today it feels fortuitous that my dad taught me the ideal gas law as a kid. I learned it as PV = nRT, which describes how a fixed quantity of gas (denoted as n, the number of moles of the substance) will exhibit changes in temperature (T) that are proportional (via R, the ideal gas constant) to the product of its pressure (P) and volume (V). Heat pumps exploit the ideal gas law brilliantly, varying the pressure of a working gas, so that its temperature changes, so that it can be used to carry heat from a source (whatever you want to cool/extract heat from) to a sink (whatever you want to warm/dump heat to).
  • A pretty good video on LED wall virtual production, a video production method that grew in popularity after it was revealed just how much Disney’s The Mandalorian relied on it. Before LED walls, a lot of film and TV – and basically every TV weather report – was produced by superimposing one video feed (often computer generated) over the part of another video feed that contains one specific color, usually green or blue. This is called “green screening,” or chroma key compositing, and it produces results that are both reasonably convincing and a little absurd. With LED walls, though, a computer generated scene is displayed on enormous screens behind the actors, and the scene’s perspective and lighting are adjusted depending on the position and orientation of the camera, and the scene and the actors are filmed all in one shot. This gives the actors a more immersive experience, and also lets them wear green without being covered up by temperature indicators.

Making & Manufacturing.

Maintenance, Repair & Operations.

  • Oxygen candles contain a mixture of sodium chlorate, barium peroxide and iron powder. When ignited, the iron powder burns at around 600°C, breaking down the sodium chlorate and producing oxygen, sodium chloride (table salt), and iron oxide (rust). The oxygen, of course, is breathable, and oxygen candles are therefore kept by miners as a backup air supply in case of emergency. A similar chemical reaction is used on nuclear submarines and on some commercial airplanes: If you’re ever instructed to “pull down on the mask to start the flow of oxygen,” you might just be triggering a high temperature (but safe!) chemical reaction in the compartment above your head.

I have lived in a rowhouse in Crown Heights, Brooklyn, for six years. The house is about 120 years old, and its exterior walls are constructed of brick, and it has become evident that those exterior walls have deteriorated significantly and are in need of extensive repairs. So, I have learned a lot about historic brick construction recently. It is an ongoing project, and one that I’ve got a thread going about in the #projects channel on the Members’ Slack. A few learnings here – some from my own research, some from other umarell Members on Slack, and some from a meeting I had with Richard Pieper, an engineer who specializes on conservation of historic masonry buildings:

  • Brick walls are constructed of wythes, which Wikipedia describes as “continuous vertical section[s] of masonry one unit in thickness.” My brick wall is three wythes thick; it looks more or less like this section drawing I drew.
  • Over time, the mortar in a brick wall deteriorates, and eventually it needs to be repointed. Our wall needs to be fully repointed: The mortar must be ground or chipped out, after which fresh mortar is installed. We want to grind the mortar out to a depth of 2.5x the joint width. Our mortar joints are about .5” wide, so we’ll grind 1.25” deep. This video describes the repointing process pretty well.
  • Our house’s footprint is a long rectangle, with one short side to the street. When you go up to the roof, which is flat, you can see that the walls extend a little bit above the roof. The part of the walls that is above the roof – something between a low curb and a stub wall – is called the parapet. When rain falls on our roof, it flows from the street side back towards our backyard, where it runs into the rear parapet. At the very low point, there’s a hole through the parapet which dumps the rainwater into a leader and downspout. Over time this area sees a ton of abuse – it’s wet for days, then the sun is baking down on it, then there’s a driving rain followed by a freeze, then a foot of snow piles up and stays there for a week – so you need to be really careful about how you waterproof the whole thing. So, intricate flashing (preferably of copper) is formed, soldered, mortared into the brick parapet wall, and lapped over by the roof membrane; this is called a scupper. Here are some nice axonometric & section drawings of copper scuppers.

Distribution & Logistics.

Inspection, Testing & Analysis.

  • You can (and should, IMO) email the US National Highway Traffic Safety Administration to tell them to include pedestrian safety in the safety ratings they assign to cars and trucks.
  • When icebergs crack, fracture, and calve, they produce a sound. The sound wave travels thousands of kilometers, and it sounds like a “bloop,” and there is an apparently famous recording of this phenomenon, made by NOAA’s Pacific Marine Environmental Laboratory, called “bloop.” Another recording, called “slow down,” is believed to have been caused by an iceberg grinding across the seafloor before coming to a rest.
  • Kevlar thread is more abrasion resistant than nylon at high speeds, but if you need your stitching to withstand abrasion, your best bet is to hide your stitches.


  • In the industry, the kind of streetlights that hang over the roadway and look like cobra heads are called, sure enough, cobra heads.
  • Two time things:
  • Time in Ethiopia, which I linked to in 2018-06-11, is just wonderful: a twelve hour clock which runs from dawn to dusk, regardless of time of year.
  • Anywhere on Earth time (AoE) is a designation that is typically used with due dates, indicating that something must be done when that date has passed/commenced, anywhere on earth. As in, “get the quote to me on 2022-05-30 AoE,” meaning anytime before midnight UTC−12:00, meaning before the day officially passes in the westernmost time zone that is east of the International Date Line.

Apple’s Accessory Design Guidelines document, a 350-page PDF containing detailed specs on all manner of mobile devices.

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