The twice-monthly Lost Knowledge column explores the possible technology of the future in the forgotten ideas of the past (and those just slightly off to the side). Every other Wednesday, we look at retro-tech, “lost” technology, and the make-do, improvised “street tech” of village artisans and tradespeople from around the globe. “Lost Knowledge” was also the theme of MAKE, Volume 17
This week, we look at the largely-lost Medieval art of timbrel vaulting structures and the related, more modern (late 19th century) system of interlocking terracotta tiles which create what are known as Guastavino domes, after their inventor, Rafael Guastavino.
The method of timbrel vaulting was developed in the 14th century around the Mediterranean, although its precise origins are unknown. The timbrel vault is also known as a “masonry vault”, “Catalan vault”, “tiled vault”, “laminated vault”, “flat vault” and “layered vault” (derived from Spanish, French, Italian and Catalonian descriptions).
A roof of tiles
Timbrel vaulting differs substantially from the Roman method of arch building, which relies on gravity. A Roman vault consists of a single layer of thick, wedge-shaped stones (see below).
The timbrel vault does not rely on gravity but on the adhesion of several layers of overlapping tiles which are woven together with fast-setting mortar. If just one layer of thin tiles was used, the structure would collapse, but adding two or three layers makes the resulting laminated shell almost as strong as reinforced concrete.
The result defies common sense, because a timbrel vault is very thin compared to a Roman vault, while at the same time it is capable of bearing much higher loads. This of course enables wider spans and gentler curves.
The Architecture Department at MIT sponsors the Guastavino Project and Guastavino.net website. Boston was the epicenter for Guastavino domes in North America because the Guastavino Company and Guastavino Company Tile Factory were based there. There were nearly a thousand such buildings throughout the US and some 65 in the Boston area. The website has information and pictures of each of these buildings, maps of their location, info on walking tours of Guastavino buildings around Boston, etc.
In 2005, members of MIT’s Guastavino research team traveled to the UK to help build a Guastavino dome for the Pines Calyx conf center near Dover in Kent. The design and construction of the domes drew heavily on Guastavino research done at MIT. Here are some pics of their build.
Structural assessment of Guastavino domes
Architectural engineer Sezer Atamturktur has done an impressive analysis of the structural dynamics and significant features of Guastavino domes: She writes:
Rafael Guastavino refined the technique of erecting thin terra-cotta tile, a thousand year old building system of ‘Catalan Vaulting.’ His company was involved with more than 1000 buildings in North America between the 1880s and the 1960s. Although Guastavino tile vaulting contributed to many prestigious buildings of that time, the structural behavior of this construction system has received little or almost no attention in the literature. It is the intention of this thesis to study this empirically designed system by using tools of modern engineering: experimental modal analysis, thin elastic shell theory and finite element analysis.
One interesting project built using a modern interpretation of these domes was the Cuban National Art Schools, an ambitious post-revolutionary (1961-65) plan to create idealized centers for creative/arts education. There were plans for such schools all over Cuba. The first one was never completed and much of the complex is now in ruins. One of the designers behind the project was a student of Antoni GaudÃ who did a lot of innovative work with the timbrel vault.
Behind an ordinary door in a nondescript room hosting several printers and copiers at PARC is the world’s first Ethernet cable. In 1973, Bob Metcalfe sent an internal memo to his colleagues at Xerox proposing a local system of interacting workstations, files, and printers. The devices would all be linked by one coaxial cable, he said, and would run within a local area network. He called the system an Ether Network, or Ethernet. By 1976, there were over 100 devices linked into Metcalfe’s local network, and it was even used to test out the world’s first laser printer, which was being developed concurrently in another research facility within Xerox. Metcalfe and his assistant David Boggs published their findings in the Association for Computing Machinery later that year. The rest is history.
Most cell phones are provided with a very basic wall-wart charger, and you usually have to pay extra for a proper charging dock. The bundled charger is often unsightly in use, being just a transformer with a cord strung out to an end table or something where the cell phone rests. If you have a cat who likes to chew through cords, as I do, this can be more than just inelegant–it can be totally impractical. It’s also a good project if you just hate, for aesthetic reasons, loose power cords strung out across the furniture.
A similar product is for sale at ThinkGeek, and that’s where I got the idea. The nice thing about my version is that it requires no tools to mount or demount, being suspended by the plug on the charger itself. So you can quickly move it around to whatever outlet you want or take it with you when you travel. Plus it costs all of nothing to build. Materials:
Appropriate empty bottle (See step 1)
One sheet printer paper
Isopropyl alcohol (optional)
Drill with 5/16″, 3/8″, and 1/2″ bits
Candle or cigarette lighter
Step 1: Find a suitable bottle
Obviously, the bottle needs to be plastic or other nonconductive material. If you try this with a metal bottle, you’ll destroy everything and probably injure yourself shorting out the wall socket. The bottle should have a flat back, more or less, so that it easily fits between the charger and the outlet. It needs to be thick and wide enough to hold your device, of course, and long enough to provide clearance below the wall-wart when inserting or removing said device. The one I made is 6″ long and works well for my phone and charger, but your own equipment may of course vary. Finally, the bottle musn’t be too thick, otherwise the force on the plug might obtain a significant “outward” component, which is probably ungood. As long as the force is mainly “down,” the limited weight of the phone, pouch, and charger should be easy for the plug to bear.
Step 2: Clean up the bottle
Peel off any labels on the bottle and remove any residual adhesive with an appropriate solvent. I love Goo-gone for this purpose–it cleans up gunk like nothing else I’ve ever used outside of a chemistry laboratory. After I used it, I gave the surface a final wipe-down with isopropyl alcohol.
Step 3: Cut off the bottle top
I used my trusty swing-arm paper cutter for this, but scissors or a razor should work fine, too. I cut 6″ up from the bottom, which turned out to be the final, finished length of the pouch.
Step 4: Cut out the tab
Use scissors to cut two slits at least 3″ long at either edge of the bottle’s back surface. These cuts form the sides of the vertical “tab” that goes between the outlet and the transformer. Round off the corners of the tab to about 1/2″ radius while you’re at it.
Step 5: Draw cutting guideline
Beginning at the lower ends of the slits you just cut, draw a downward-sloping line around the bottle, which levels out about 1″ from the bottom of the bottle in the center of the front panel. Then draw the mirror image of the line up the other side. If you can, draw the line such that cutting it completely away will give the shape you want, so you don’t have to clean anything off the part you’re going to keep.
Step 6: Cut sides and front of pocket
Using a sharp utility knife, cut out the front and side profiles of the pocket. Clean up the edges by scraping with the edge of the blade. Once you’ve got the shape you want, you can “fire polish” the edges by running the flame of a lighter or candle over them briefly. This will melt away any loose frizz and round over the cut edges in a pleasing way.
Step 7: Mount the drilling template
Print out the image below at 300 dpi. It should come out 1″ square. Cut it out and tape it in place about 1/2″ from the top of the tab as shown.
Step 8: Drill holes
Drill three holes in the template as indicated, and then one more hole in the exact center of the bottle’s bottom to pass the charging cord. The diameter of this hole may vary; 1/2″ was necessary to clear the “micro-USB” connector used on my phone. To ensure accurate placement, step drill the holes, starting at 1/8″ or so and then drilling to full size in a second operation. Remove the template and “fire polish” the edges of the drilled holes as before.
Notes and ideas
Instead of drilling a hole in the bottom of the bottle, you might try cutting a slit with a razor just long enough to slip the power connector through. The sides of the slit will grip the cord a bit, and should prevent it falling out when you don’t want it to. I haven’t had any problems with this, but I’ve also got an unusually bulky connector on my phone.
Also, if it bothers you, you could splice the cord on your charger way down to eliminate the big hanging coil when the phone is in place. Cover the joint in the cable with black heat-shrink tubing to make an attractive splice, or take the transformer casing apart, make the splice inside, and put it back together. It’ll still have to be insulated, of course, but it won’t matter so much if it’s neat.
The tradition of improvising a chess set from whatever’s on hand is probably as venerable as chess itself. Chess culture is chock-full of sets put together from odds and ends of every description, but here I’m only focusing on sets built from mechanical and electrical bits–mostly nuts, bolts, and washers of various flavors. If you’ve got a good one I missed, please do link it in the comments.
If you’re interested in making your own and want some guidance, Mother Earth News has a nice tutorial.
I’ve seen this thing referred to as an “Ocean Mat,” a “Prolong Knot,” a “Ladder Mat,” and a “Sailor’s True Love Mat.” Whatever you want to call it, it’s a noble expression of the manly art of knot-tying, and this tutorial at the UK’s Scullion Enterprises will show you how it’s done.
Over on GeekDad, Dana Bostic came up with this simple backyard cool-the-kids “hack” — a hose sprayer set to “shower,” zip-tied to a tall step ladder pouring down onto a trampoline — so the kids can work up a sweat and cool off at the same time!
Bridging the gap between the “real world” and your computer, the Arduino Projects Pack takes you further into the world of physical computing. We’ve included all sorts of cool electronic parts this time that help you delve deeper into the true capacity of the Arduino. You’ll experience what the tens of thousands of engineers, designers, artists and hobbyists already know about this awesome and educational prototyping platform.