by mezmo » Thu Dec 20, 2012 10:02 pm
Hi droid,
I had the same success that you did when I looked at their website -
not much !
But to me it just looks like or very similar to what the method is for
a Bow-Top Vardo. The end walls are framed for door and window and
the round shape. Here, they look like they used a catenary arch shape,
then longitudinal [lengthwise - front to back] pulins or spars go from
front to back to define the roof shape. The metal wire grid/fencing
[or whatever it is - I'd make sure to use galvanized or the plastic coated
type to ensure no rusting problems] just gives a somewhat more rigid
base/support for their insulation layer and vinyl covering. A Foamie
builder would just lay their foam sheets over it, then their fabric and
fabric coating over that in place of the insulation and vinyl sheet.
Since the thinner foam sheets are bendable, maybe multi-layer staggered
overlapped sheets of them could be used glued together or just kerf
thicker sheets, If that is what you have, depending on each builders
circumstances/preferences.
It just occurred to me, that you could make the frames and purlins/spars
out of appropriate sized galvanized metal electrical conduit [EMT I think
it's called.] and then lash-wire the galvanized/coated grid over-n-to that,
then continue with the foam sheeting etc., My personal feeling is that PVC
conduit/piping wouldn't be strong enough or long-lived enough
for use as 'framing'. I once saw, somewhere online, where a small dome
was built by bending EMT into curves and the vertical and horizontal
curved tubing was then lashed together with a twine and then that lashing
was coated with epoxy. There's also a builder of bamboo framed bicycles
that lashes the frame pieces together with a hemp twine and then epoxies
that [they formerly used carbon fiber for lashing but found the difference
in thermal movement between the bamboo and carbon fiber caused problems
but the hemp twin and bamboo were thermally compatible for expansion
and contraction]. Maybe fiberglass 'twine' or ribbon [Are there such a things ?]
could be used for the lashing of a galvanized tubing frame and the galvanized/
coated wire grid and then use an epoxy suitable for metal to coat that and
lock them together in place.
Sorry - got to rambling there !
Cheers,
Norm/mezmo
If you have a house - you have a hobby.