I've been very successful by covering the bi-filiment tape with an opaque
metal foil tape. This gives the strength of the bi-filiment with the
durability of the metal. I overtape the bi-filiment to ensure a good bond
for each joint as I find the bi-filiment has a very poor adhesive. I also
found (through bitter & wet experience) that to have a waterproof structure
the tape must be pressed into every fold & crevasse of the panels. The
panels are not really flat and every fold in the foil will channel water in
a rainstorm. I think a spray sealer of some kind would be useful to help
waterproof the yurt but I haven't tried it.
My last hexayurt was 6' tall at the sides and 10' tall in the middle. It
also folded but not in as neat a box as you describe.
chasomatic
On Thursday, March 28, 2013 1:17:41 PM UTC-7, Jacob Rodriguez wrote:
>
> So, I'm going to be building a quarter sized nearodesic polyhedron
> ("quad") dome (1 rmax sheet = 8 triangles) for BRC this year.
>
> My foamcore and masking tape prototypes (1:12 and 1:5 scale) have been
> going well. I'm learning how to do the tape hinges, and how to miter the
> edges with a razor and angled metal guide. I'm thinking that the full size
> version will be relatively easy to prepare and construct. My end result is
> a 6' high, 12' diameter dome that folds down into a 4' x 4' x 15" high box.
> Minimal tape is required as all but one edge of each quad is hinged with
> fabric and adhesive. Only the top square, and 4 "corners" need to be fully
> taped together.
>
> I'm seeing lots of people commenting on how the BFT (bi-filament tape) is
> not really UV resistant, so it flakes off eventually. Also, that it's
> barely a semi-permanent solution, even if you do tape hinges instead of
> one-time assembly. I've considered many different types of ways to join the
> triangles that would last more than one or two times:
>
> - zippers (needed like 400 of them, really really expensive)
> - button snaps and straps (would glue on the snaps to the boards, then use
> a strap to snap them together; this is not weather proof at all)
> - velcro (again, pretty expensive if you use the really good velcro, which
> is likely the only way to guarantee structural integrity and
> 'weatherproof-ness')
> - magnets (even using strong ones (N45), embedding them in the edges of
> the triangles, they could jsut fall out, and still not weather proof. also
> $$$)
>
> ..and a couple of other ideas. I've learned that putting metal
> hooks/rods/bolts (binder clips) through the boards will just rip through it
> with a strong enough tug. They could end up just getting loose and boring
> out big holes. Using plus-shaped ("+") hooks/rods to fasten some sort of
> fabric over the joints are slightly better because they resist being pulled
> like a wire cutter through the board, but you would have holes in the board
> and water could get in. Also, excessive force would also just make the
> holes looser and ruin the boards eventually. But the idea of using some
> sort of fabric seems to hold merit.
>
> My main goal is to build something that can easily be packed away, and
> assembled multiple time. Realizing that the main principles of a good BM
> structure are to seal out rain, dust and light, I think I've come up with a
> possible solution, but I'm curious why I can't find anyone who has tried it.
> * I'm hoping to get some cautionary tales or some encouragement on using
> sport nylon (as opposed to ripstop), and some Super 77 or 80 or 90 spray
> adhesive, instead of the traditional tape.*
>
> The cost might be a little more expensive up front (depending on some
> factors), but I'm thinking that the nylon will last much longer than just
> about any tape and is probably just as strong (if not stronger) than BFT.
> From what I've read, a lot of people end up using some 77 spray anyway
> because of the lubricating residue on the boards. I'm curious if it's more
> UV resistant (or at least the adhesive would be) and therefore survive the
> endless sun bathing better. Also, the concept of cutting fabric into strips
> and using spray adhesive as a backing gives the user many more options when
> it comes to materials (stronger fabric and/or stronger glue), rather than
> just limiting to such a rare find as 6" BFT. Though I'm sure that sport
> nylon "tape" is even more rare. You can also make the strips as wide as you
> want, so you are not limited there either.
>
> I've built a prototype of a hinged triangle using foamcore, sport nylon
> and Super 77, which seems very, very strong. Stronger than masking tape
> anyway. I'm thinking that while it's not waterproof out of the box, I could
> always spray with some scotchguard, or tape over everything with the foil
> tape. Foil tape would also help any concerns on fire-hazard as the adhesive
> is quite flammable. I put a hairdrier on it for about 10 mins on high, to
> see if excessive heat made the glue loosen, but it did quite well. I'm
> thinking the higher temp ratings of 80 or 90 adhesive will help in that
> area. Maybe instead of foil tape. I can spray with some sort of coating
> that will protect against fire and water at the same time.
>
> For cost comparison, my project would be using about 6 rolls of 60yd tape.
> That's about $20 a roll. Plus about 4 rolls of foil tape (for outside only)
> at another $20 a roll. I'm thinking that a can of adhesive will last quite
> a long time, so I may only need about 3 cans at about $20 a pop. The fabric
> is not that expensive (maybe 5 dollars a yard), so I think all in all, I
> might come out saving a little cash (if any at all), but ending up with a
> much more permanent/reusable solution.
>
> Anyway, what do you all think? I'm going to be purchasing a piece of
> polyIso to test. I'm going to make a single "quad" using this nylon and
> adhesive, then leaving it up on my roof for a week or two to see how it
> handles the weather. It's Santa Monica CA weather so not quite the same,
> but should give a good indication as to whether it will survive at all.
>
> Thanks for reading!
>
>
>
>
>
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