fiber-matrix
5.12: composite tech:.
here is foam but used as a mold for fiber-epoxy,
Zote foam from Mark Mueller at Windwrap Fairings
. he used contact cement on zotefoam to itself and to velcro .
5.23: foam
. could use art`gift/apt`bedroom`floor.mat
as stronger version of shell than the camping mat .
5.28: foam/stays round:
. the roundness of the shell around the wheel wells
can come from the shell if something stiff is used as the skin,
such as the camping mats .
. in addition to tent fly, try fabric store .
rip-stop nylon fabric
8.30: todo.gear/composites/foam shade:
. mobi foam may need cover from sun
see kite place for carbonate finish sheets,
and kevlar thread .-- see how this is uv protected .
tech.gear/composites/rod-structuring
5.3: pull.ropes:
. instead of relying on shear-grip alone,
when doing rod-composite structures,
also use rope along the length of the rods,
as is used for holding the sanctum together;
eg, when making an H-shape,
you would run rope along the horz.rod,
tying the two verts together .
5.6:
. when the joints are being bundled by a composite,
there will be several layers;
and the pull.ropes can be applied between the 2nd and 3rd layers
-- atleast it shouldn't be under the first layer,
because it would get in the way of the composite making the most
densely fibrous contact possible to the rod .
5.15: pull.ropes for bows:
. string comes up to rod pocket into a seam
like when a drawstring is closing a pouch
. how is rod`pullstring following the curved rod of a bow?
the strongest and easiest is to bring string to both pockets;
then wind a double helix around the rod .
. to be modular, keep a metal ring between pocket and pull.string
perhaps fashioned from galv'wire .
[23: . but a pocket will give the string more support, less wear .]
. alt'ly,
a piece of strap is folded to form both a pocket and double loop
then a loop for each helix
then make pull strings wrap around the pocket to reinforce its stitching .
5.25: pull.ropes/strategic placement:
. both pull.ropes should be in both loops to pull them evenly .
[5.28: they should be symmetrical,
but the can go through just one loop .]
5.25: pull.ropes/loop reinforcement:
. to reinforce the pull.rope`loop, keeping them open,
even after bundling T-joint with fiber-epoxy,
leave in each loop a bike brake cable housing
(or if need larger for both pull.ropes to fit,
then use some rubber hose from tire pump)
. the housing may help keep the fibers from cutting eachother .
5.6:
. keep in mind that epoxy is brittle like aluminum,
so it should only be involved in situations where flexing is minimized;
that's why, altho' aluminum is stronger per weight than steel,
this is so only in tubes that are of larger diameters,
offering greater triangulatory resistance;
so,
you don't want to try making a filler out of very thin rods:
keep the compositing action near the joints
where thickness can be built up relative to the surface area .
5.12:
. to minimize dependence on testing epoxy strength,
the primary strength should come from the stitching
like a tent holds poles together .
. the epoxy will be there just to protect the threads from wear .
5.25: overlapping rods
. when overlapping poles to make an extension
and using a composite binding (rope with epoxy or caulk)
then reduction of wiggle room could be sufficiently done
simply by addition of a 3rd rod to the bundle .
5.30:
. 2 rods can fit in one al'beam at the same time;
so, they can be like female-female connectors .
5.31:
. while the pull.ropes will keep overlapping rods from lengthening,
the overlap-joint must somehow prevent shortening .
. when using the one al'beam as a female-female connector,
the way to do this is to make the al'beam longer than the overlap,
so that each end of the al'beam will allow only one rod .
. the pinched part is wrapped in fiber-matrix
both to prevent the al'beam ends from being a cutting hazard,
and to strengthen the fragile crimped aluminum .
5.31: overlapping rods/nylon.strap:
. is there some nylon.strap-version of an overlap-joint:
. T-joints (the kind using strings) on both ends of both rods,
could use their pull.ropes to provide both the usual pull-apart resistance,
and a push resistance: the ends that are near the overlap,
their pull.rope loops would share a rope .
. a joint specialized for overlaps could be like this:
a 3" strap uses 1" loop back to form a pocket,
and then another 1" strap is sewed on the part of the longer strap
where there is no pocket .
. the short side of the pocket should include a pull.rope loop .
. a nylon.strap joint could also be useful in conjunction with an
al'beam fe-fe connection by filling this sewed strap piece with matrix
instead winding a matrix-slathered string around the al'beam ends .
5.3: gear/composites/shell-to-rod attachment:
5.24:
. the shell is partially nylon like a tent for toughness,
and then also some sort of insulation for reflecting desert heat .
. this insulation can be either foam mats
(as for placing under sleeping bags, or at a stand-up station)
or it can be reflectix, which is not as tough, but great at insulating .
. the foam can be arranged like plates on a rhino,
then along the cracks of these plates are wide bands of nylon fabric;
this gives a lot of surface for many connections .
5.3:
. the mat is sewed to cloth with stitches 1/2inch apart
-- the same as its thickness .
5.24:
. there is not eno' strength along the rod to epoxify the flange .
-- that fact nixes this idea:
5.3: "(
. the insulation is attached to fiberglass rods by a composite flange:
. the general flange pattern is to form a pocket of several epoxied layers
on both sides of the the rod,
perhaps also gluing the rod to the fabric,
but leaving edges unglued for easy sewing to the mat or other flanges .
-- if smearing the entire pocket with epoxy to strengthen the threads
then the flange could not easily be reused
in case the shell or was damaged or the threads broken .
) .
5.24:
. attaching foam to anything by stitching is very labor intensive;
that fact nixes an any idea that shell should get some of it strength
from triangulating the rigidity of the foam;
eg:
5.3:
. "(. the rear cone [mobi/trike`shell/tailbox] can get strength from
the rigidity of its own camping mat panels .
)
5.6: rod-structuring/application of the matrix:
5.24:
. for some rod-to-rod connections it is better to use fiber-epoxy
than to sew pockets together;
this is where technique of applying the epoxy
can be critical to the strength of the joint .
5.6:
. once the epoxy or other matrix is mixed,
simply wad strips or strings of fiber into the mix,
then after working it in,
slide down fiber with pinched fingers to wring out the excess,
and apply to joints that are already held together with a wire tie .
. practice ahead of time winding the string in place,
keeping in mind that it has to be very tight,
so it is the fiber that is filling up most of the volume,
not your matrix (the epoxy) .
. pre-knot the end of the string,
and then when the winding is done,
use that knot to catch a clamp to weight the end down .
5.12:
. the test can be part of the manufacture
by making pockets that tightly fit pole via sewing
and pole is slathered with epoxy to see how holds to fabric,
then pockets are sewn together .
-- re: 5.3: try the epoxy on practice parts first .
rod & beam structuring:
5.12:
. the design is extensible and repairable in layers
. the core is a flimsy pole,
while stiffening can be done incrementally by
splinting on layers of aluminum.beam
. if an aluminum.beam is bent then it may be floppy
but the shell will still be usable until home for repairs .
5.24:
. a network of aluminum.beam is also useful for
minimizing the effects of a cutting gash
such as when caught on something while in motion
or during a vandalism attempt .
. when a network joint can be floppy
it can be constructed by stapling the ends together
with a twisted ring of wire .
. if stiffness is needed, then the joint can be bolted,
and/or reinforced with epoxy-fiber .
5.25: aluminum.beam triples:
. the aluminum beams can be triple bundled
to form h-structs at their ends;
ie, during a T-struct with the bottom being a triple,
and the top being a rod,
the concavity at the end of the triple will fit around the rod .
. the triple can be stapled around a rod by wire loop,
then goop with flashing caulk
then cover goop wih bundles of rope loops around the triple .
. picture the triple with the rod taking the place of the middle beam
about a centimeter deep, so there is room to have
bindings around the triple on both sides of the rod .
. the staple goes through at a 1/4inch below the rod,
and also just above the rod,
the middle beam above the rod is not connected by the staple
but is there simply to provide filler to prevent collapse
during bundling of the beams above the rod .
5.27: aluminum.wire
. sculpting the fenders can be easier with the aluminum clothesline wire
. twisting wire can make random networks .
. a bit of epoxy to hold the twist on its base,
and then the whole net is kept in place by fabric sewed onto it .
5.28: sewing with string:
. sewing needle for string ?
can be done by small loop of thread holding string,
and using an awl to widen holes .
rod-structuring/nylon straps/T-joint
5.24:
. the most important pocket is holding 2 rods in a T-structure,
where the base of the T is part of a bow,
so that pocket is also got a pair of loops for the pull.ropes on the bow .
5.16:
. a T-shaped rod connection can be done with a single strap,
doubled to form 3 loops:
. form loop for rod connectiong to bow;
run the strap down the bow`s rod and then back up
to form the loop for the top pull.string;
then run the strap back up to bow`rod`end
and down the bottom side of the bow`rod,
ending the strap with a loop the bottom pull.string .
finally, the sandwich of strapping around the bow`rod is stitched shut .
5.24:
. a major design variation at this point
is whether to create a T-joint is strong eno to
keep the top from breaking and sagging,
or instead design it with the sag built-in,
so that the top rod is hanging in a loop that is tangling from the bow`tip .
. yet another version is to be both dangling
and resting in the corner formed by the bow's rod and its string:
here the same loop that holds the bow`string could hold the T-crossing rod .
5.30:
. this is an improvement on, the T-joint:
. the previous version tried to do the whole joint with just one strap;
but for getting the cross-loop near the end of the pocket,
that meant that the piece was too thick to machine-sew in some places
meaning that it took longer, and the result was loose or messy .
. the new method just uses some rope in place of the cross-pocket:
just sew a pocket with loops at the end for the pull.ropes,
but wherever you want a cross-loop, leave a couple of 1-ft ropes
that are perp to the pocket's stitching on the sides
and are inside the pocket so they get run over by the stitching .
. alt'ly or additionally,
the loops of the rope can be sticking out of the stitching,
so it has a P-shape .
. bring the ends of the rope outside the pocket
to insure that the rope got run over by the stitching multiple times .
rod-structuring/nylon straps:
5.24:
. if you did need the pocket to adhere to the rods
then one way to make sure the pocket hugs tightly during epoxy cure
is to wrap string around the drying pocket;
when that dries, then the string can be removed
and another layer of fabric-epoxy applied .
. if you have slow-curing epoxy,
then you might try doing all the layers at once .
5.15:
. the design should not allow the parts to press directly on the stitching;
eg, if you have a wide nylon band,
then you could double-fold it to make a pocket where
2 of the 3 sides are held by fabric alone rather than stitching .
5.16:
. a single 1"-wide strap fits around a pole,
to make the joints for connecting string to rod,
which is good for making a stand-alone bow;
but, consider how the joint lets the bow points attach to other rods,
in the case of the TT-struct that is extending the chair`back,
there is a perp horz' which has the same need as the pull.rope
only the sheath is larger to fit a rod .
5.24:
. at one point in the design (the top rim of the clam`bottom),
there is a need for some rods to be bound overlapping,
in order to form one long rod out of 3 shorter ones .
. this can be done without having to know how much overlap is needed,
like so:
. 2 of the rods come together at the back to form the tailbox`top,
these are then fed through the loops of the TT-struct
extending from the chair`back .
. a bow is made for the front, which has a version of bow`string in the middle,
so that rather than looking like a D,
it's as if an H had its top verts bent inward to connect with eachother .
. this can be done with a system of pull.ropes that not only keep the pockets on,
but also help keep a couple of mid-way bands suspended in place .
. with the front and rear subsystems in place,
it becomes readily apparent how much they overlap .
. the entire tear-shaped struct can be pull.roped to keep the overlaps together .
5.30: rod-structuring/nylon straps/X-joint:
. the x-joint is has no 3-sided pocket,
it's just 2 perp loops stapled together like so:
a 2" strap is viewd vert'ly;
a 1" strap is placed parallel 1/4" from the top;
the sides of them are sewn together -- to hold a vert.rod .
. the bottom edge of the 2"strap is flipped around
to be aligned with its top edge;
and then these edges are sewn together -- to hold a horz.rod .
gear/composites/rod-in-tube/pull-rope doubles as anchor.line:
5.30:
. instead of having a pull.rope joint at bottom of seat`back`s extension.rod,
attach its top pull.ropes to the bottom of seat or to some other point on trike
so that the pull rope will both keep the top`T-joint on its rod,
and also keep the rod in seat`tube .
. Copper is PLUS 0.34 volts OVER Hydrogen.
therefore copper would be sacrificed to the aluminum.
then the aluminum will also be corroded.
aluminum is non conductive and hence zero with respect to hydrogen.
