I won't argue one way or another on the beveling issue, but I will counterpoint
your experience with mine: I used a skilsaw with a nice long blade, which cut
through the polyiso like butter. Since you have to cut a straight line anyway,
it was only marginally more effort to set the angle on the saw and go that way.
The head-scratching and equivocation about where to put the bevels was MUCH
more overhead. On my second yurt, we used a tablesaw, which I'm kind of keen to
do again.
...and I echo your experience about having everything fit together: AAAHHH!!!
Cheers,
Steve
--
[T]he unreasonable success of mathematics in the natural sciences...
is a wonderful gift which we neither understand nor deserve.
-- Eugene Wigner
On Jul 26, 2011, at 1:56 AM, Vinay Gupta (Hexayurt Shelter Project) wrote:
> 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
>>
>>
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>>
>>
>
>
>
> --
> 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
>
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