Extremely useful, Steve, thank you. If that bears out and all works, we should put this email on the Wiki for people who want to go down the bevel route.
I've gotta say that the time I manually beveled several hexayurts using a craft knife and a wooden guide was about the worst of hexayurt construction - massive amounts of irritating fiberglass dust, constantly resharpening the craft knife on a little sharpener (one of the little pocket jobs with two crossed ceramic rods) and so on. Then I put the hexayurts together, and they fitted like injection moulded plastic parts: practically *clicked* together. But the process, with the tooling and expertise I had at the time (this is 2006) just wasn't worth it. Satisfying results, somewhat stronger, probably, but not enough to be worth recommending as the standard approach. In general I've tended to advise the least work, least risk hexayurt, and now we've got a wider community of practice and a lot more expertise available (i.e. it doesn't all have to fit into *my* head any more) I'm glad to see bevels and the H13 and possibly a big dome etc. all coming back into play as options for the more technically ambitious builder. Do take pictures and blog/post/document. It's how people learn. Video, too, even low quality video, is incredibly useful for propagating ideas, so if you can, shoot some too! Thanks for sharing the work, Vinay On Tue, Jul 26, 2011 at 6:31 AM, Steve Upstill <[email protected]> wrote: > I just dug out this recipe for how exactly to cut the panels of an H12 > hexayurt. On my second go-round I still did a bit of head-scratching and > hemming and hawing and STILL had to redo some of my cuts, so I resolved to > make it all explicit. This takes you through making the cuts, then to doing > the taping. > > The reason I'm sending this to the group rather than posting it in a more > permanent place is to get someone else involved in debugging. I'm somewhat > concerned that the endgame (that is, taping the joints) is a) clear enough > and b) NOT WRONG. So, anybody care to kibbitz? > > Don't know if this will help anybody, but it's my stab at contributing to the > body of documentation. Take it for what it's worth. > > Cheers, > Steve > -- > Activity should never be confused with progress. > -- Peter Allport > > ORIENTATION > > You're going to be building a hexayurt from twelve 4 x 8 foot panels. Six of > them will stand up on the ground (short edge up) to form a hexagonal wall. > The roof will be formed from six triangles that are 8 feet at the base. You > get these by cutting the other six panels diagonally into right triangles, > then joining them on their 8' edges to form six isoceles triangles. When > these sit on top of the wall, they come together at a point to form a > hexagonal cone. > > > BEVELLING THEORY > > The ideal surface we are shooting for has walls that are exactly 4x8 in size. > Since our walls have thickness, the panels need to be bevelled, so that the > thickness of the walls proceeds inward from this ideal surface. Similarly for > the ceiling panels. If you remember that the bevels are always "inside" the > ideal surface, it makes understanding things a little easier. In fact, here's > a rule: the INSIDE surface of the panels will always get the most cut out of > it with the bevel. The OUTSIDE surface shouldn't be cut by the bevel at all. > The bevel should make a sharp corner exactly at the edge of the outside > surface. > > CUTTING > The walls are easy: take six panels and bevel ONE LONG SIDE AND BOTH SHORT > SIDES on a 30° bevel. THE BEVEL SHOULD GO INWARD IN THE SAME DIRECTION FOR > ALL THREE SIDES. Ideally, the saw kerf should all be on the edge and not cut > into the outside surface. You get quality points for picking wall panels that > have dings in the edge (especially the long edge) and bevelling so that the > ding gets cut away. > > The roof panels are slightly more complicated. The short edges of the panels > you start with--which will join the tops of the walls--will also be cut at > 30°. The edges where the roof triangles join--the hypoteneuse of the > diagonally-cut triangles--are ideally bevelled at 14.4°. Call it 15. > > > This is how the roof panels are cut. The darkest surfaces are the INSIDE, > with the bevel cut into them. The lightest surfaces are the original edges. > The medium-gray surfaces are the cut bevel. > > 1) Bevel both short edges of all six panels to 30°. Once again, make sure > that the bevels cut only the inside face and the edge, leaving the outside > face intact. > > 2) This is important: Divide the panels into two sets of three. Mark the > OUTSIDE surface of the first three with a diagonal line that runs from right > to left. REVERSE THIS FOR THE OTHER THREE: mark the outside surface with a > diagonal running from left to right. Now cut all six panels along the line. > Quality points for cutting them right down the middle so that each half loses > the same amount. (NB: if it's not clear to you why you have to cut three in > one direction and three in the other, lay six panels out on the ground > abutting along their long edges. Now conceptually join them at their edges, > then imagine how to cut five isosceles triangles out in such a way as to > leave one right triangle from each end to form the sixth. See how the > diagonals alternate from one sheet to the next?) > > 3) Bevel the diagonals to 15°. Again, only the inside surface gets cut, > leaving the outside surfaces as right triangles exactly 4 and 8 feet on a leg > (minus the diagonal kerf). At this point it wouldn't hurt to spray a bit of > paint or otherwise mark the inside (say) surfaces of all your pieces. It's > fairly obvious what the inside of the wall panels is, but it's not at all > obvious what the inside surface of the roof pieces is, and you CAN go astray > in the next steps, so make it easier on yourself and mark them. > > Now you're ready to assemble the walls and roof. You've got eighteen > panels--six rectangles and twelve triangles--with, among them, 60 exposed, > MOOP-y polyiso edges, so get to work taping those up. > > Now that you've got a crapload of pieces with no exposed polyiso, take a > break and ponder on joining the wall panels: your goal, in hinging two panels > together, is to make sure that when the joint/hinge is formed, the two-panel > edge that runs across the join is flat (no "jump" at the joint between > panels) and straight (it doesn't deflect at the joint). These are the two > factors that make the yurt dodgy to assemble, and there is some "wiggle room" > to control, so you want to get those right. Best to do that by backing this > transverse edge up against a straight edge or surface while taping. > > Here's what you need to know about making a folding yurt: if you imagine the > thing assembled, then going around the circumference from one panel to > another, you have to ALTERNATE putting the hinge on the inside and the > outside. If you do this rigorously--for both the wall pieces and the roof > pieces--you can hinge all six wall panels into a single folding stack, and > the roof triangles into two such stacks. The reason you want the roof panels > in two pieces is to fold them into two right-triangular bundles that you can > lay next to each other in a rectangle (think about it). Keep your head about > you, though: if you expect them to nest perfectly for shipping in a perfect > rectangular bundle, you need to build the individual isosceles roof > triangles--on the edge that joins unbeveled edges straight down the > middle--three hinged/taped on the inside and three on the outside. > > You now know what you need to know to assemble the walls. (Need I mention > that the unbeveled edges need to be all lined up when you're done? That's the > base, you know...) Go forth and tape: come back when you emerge with a > single, satisfying, end-hinged stack of 4x8 panels that all sit on the flat > side. > > Now, the roof: Note that each of the three original, rectangular panels that > turned into one your two roof sets (three with left-to-right diagonals, three > with right-to-left, remember) produces two identical right triangles, so you > now have two sets of six. Pair them up, one triangle from each set, and join > them along their long, unbevelled edges to form isosceles triangles with an > 8' base (2 of 4' each, right?) and the kerfs around the outside going > inward--or outward--as long as each pair is consistent. MAKE SURE THAT YOU'RE > JOINING INSIDE FACES TO INSIDE FACES--or, equivalently, that the bevels all > go inward. That still leaves you free to choose which side to tape: again, > for folding purposes, three of these joints should be taped on the inside and > three on the outside. You can then take three like-hinged (inside or outside) > triangles and tape THEM together on the OTHER side: the three that are taped > on the inside will join together with outside hinges, and vice versa. VOILA! > two sets of six right triangles that fold up to perfectly nest to form a > rectangular bundle. > > Now, take your bundles and your tarp to a local parking lot or something and > practice putting it together. Not only does this debug your execution of all > the above, it gives you some practice that will come in handy on the Playa. > Handy suggestion: when the building is put up, locate it appropriately on the > tarp, and when you're happy with it take a magic marker and draw where the > corners go. > > Finally, two more tips: if you intend to run your fabulous, strong, 6" > bidirectional filament tape up and over your yurt, you will find it very > difficult to do. These buildings are not small, and they're taller than you > are by quite a bit. I had a bit of trouble the first year, and my plan for > the second year (undebugged, frankly), is to get two paint rollers (just the > wire-frame things that the actual rollers fit on, not the rollers themselves) > and some long extensions for manipulating the tape rolls over the top of the > yurt. > > The second tip concerns teardown: ripping the tape off your roof can be a > real hassle (see previous paragraph). But if you lay some, say, 50-lb. > fishing monofilament in the joints that you're going to tape, making sure you > can get to it afterward and that it's sticking through the bifi, then you can > use it to CUT your bifi exactly where it needs to be cut for disassembly. > > There ya go. I hope I got it all right. > > Cheers, > Steve > > > -- > You received this message because you are subscribed to the Google Groups > "hexayurt" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/hexayurt?hl=en. > > > -- Vinay Gupta Free Science and Engineering in the Global Public Interest http://hexayurt.com - free/open next generation human sheltering http://hexayurt.com/plan - the whole systems, big picture vision "In the midst of winter, I finally learned that there was in me an invincible summer" - Albert Camus Twitter/Skype/Gizmo/Gtalk/AIM: hexayurt UK Cell : +44 (0) 7500 895568 / USA VOIP (+1) 775-743-1851 -- You received this message because you are subscribed to the Google Groups "hexayurt" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. 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