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telescoping copper Wednesday, November 17 2010
Heavy rains last night raised the water table without creating all that much surface runoff. While there was no water running in the ditch separating our driveway from Dug Hill Road, the greenhouse had flooded all the way up to the four inch drainage pipe that sets the upper limit of how much it can flood. This was the first time it had flooded since I did all the recent excavation around the well to turn it into something of an indoor pond. Completely full of water, this cistern contained several hundred gallons (I would estimate three or four hundred gallons). Being so deep and clear, the water was compelling. I just stood there looking at it for awhile, though it was utterly silent and only moved a little (mostly when I shut the greenhouse door, momentarily changing the air pressure). Since there still is no floor over this cistern, the water cutoff my access to the rest of the greenhouse. Eventually, though, I figured out how to make my way around the cistern by balancing on the narrow ledge I recently created along the bottom of the greenhouse's eastern wall. (The base of this ledge hadn't completely cured before it was flooded, though it seemed to continue curing under water throughout the day.)
At some point in the late afternoon, I filled in the one remaining low spot in that ledge (a low spot whose bottom was still above the level of today's flooding). To do this, I used Portland cement, salvaging some from a bag nearly a year old. This required me to grind a bunch of old it back into powder (due to humidity in the air, it tends to clump into hard nuggets over time, though —unlike old concrete or mortar— this doesn't seem to affect the strength of the cement one can make from it).
As forecast, high winds blew through the area today, though they weren't quite as strong as I'd feared. The provisionally-supported main hydronic panel survived all of today's gusts, as did the huge green tarp I'd lashed over it to protect it from the elements (though it did flap around a lot and occasionally inflated like ship's sail).
For the past couple months I've been thinking about a plan for another copper pipe lamp design. I've made a lot of lamps with light bulbs on the end of swinging arms, but for this design I wanted to make a lamp that could telescope down from the ceiling to be a reading map and then pushed back out of the way. To get the telescoping to work, I'd have to nest small copper pipes within larger ones and allow them to slide within each other without pulling out or sliding too effortlessly. Today I built a telescoping set of pipes that can extend from about 30 inches to about 90 inches. The set includes a 30 inch piece of inch-long pipe, a 32 inch piece of 3/4 inch pipe, and a 33 inch piece of half inch pipe. To guide one pipe within the next, I used fittings to adapt each outer pipe to the one it contained. This adapter would be soldered to the outer pipe but not soldered to the inner pipe. Since fittings generally have stops punched into them to keep pipes from being inserted too far, I had to file these stops away to allow for the smooth passage of the inner pipe. To keep an inner pipe from pulling out of an outer pipe, I soldered a coupling to its topmost end, where it not only could serve as a stop, but could also supply some friction to keep the telescoping from being too effortless (I don't want telescoping to happen from gravity alone). To make the coupling supply friction, I cut some crenellations into it and bent out little rectangles of copper. This is all too complicated to describe in text form, so here is a diagram:
Note that "top" as I'm describing it is left in this drawing.
The telescoping pipes, partially extended.
The telescoping pipes, fully extended.
The top end of the telescoping pipes with no extension, showing the nesting of all the pipes and couplings I used as stops. The blob on the left is a brass "rubbing hand" I soldered to the half inch pipe to increase its friction with the 3/4 inch pipe. The dirtiness is from pine sap, also added to increase friction.
This evening I took my first bath in over a week, reading some of a compelling non-fiction book Gretchen just finished called In the Land of Invented Languages.
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