These are our custom made one of a kind
fiberglass legs. There isn't
enough room on this page to describe why they are
so unique.
But I will tell you one thing, they weigh over
thirty pounds.
I don't have to worry about stress cracks with
these!
Getting the low luster additive formula
correct for the gray color we chose
was difficult. The above photo shows the second
attempt at modifying the
formula. It was critical for me to achieve low
luster, not only because
it is the correct finish for a B9 robot, but I knew
if we had finished
our parts with a glossy finish, taking flash still
photos would have made
for very overexposed photos, not to mention the
components would pick
up reflections from surrounding objects, as you can
see from the photo. It
took three attempts to get our formula correct. The
first photo at the top of
this page shows the finished product. Of course
this is the hip section of
our legs prior to bolting on the left and right leg
sections.
This is a close-up of the leg gasket that
Mark Thompson discovered not long
ago. The gasket was typical for the "Hero" and
"Long Distance" robots.
Nice sharp eye, Mark!
A final test fit of the legs prior to
cleaning off the over spray. Also, those very
familiar with fiberglass legs may notice the leg
section attachment points
have been hand sculpted and built up by
approximately an inch or more.
If you look at the very front of the leg section,
you can see the original height
of the lip which is only about 1/8" high. The lip
is the part that actually contacts
the bottom of the hip section where the bolts are
coming through. The lip height
of 1/8" was consistent all around the top for both
leg sections. When attaching
them, prior to making this extensive modification
to both legs, they were
badly cocked inwards and uneven, especially the
robot's left side, which was
completely unacceptable.
The five minute easy fix was to add over an
inch of washers to level everything
and straighten them up. The problem with the easy
fix was that if you stood
far enough back from the robot, you would see a lot
of light coming through
them due to the washers creating such a large
spacing. In the end, I felt this would
diminish the rest of the work on the legs and
ultimately I chose to spend a month
not only repairing deep stress cracks, but sculpt a
new inner lip to both leg sections.
After each layer was added, slowly building
up the height, work
had to stop and the leg would then have to be
bolted on to the hip to confirm
a seamless, level, and even fit . Each leg section
required dozens of test fits while the
new section was being sculpted. Any high spots on
the inner lip area that I was working
on resulted in the outside lip, which is visible
over the hinge area, pulling away and
actually lifting up. This modification was the most
tedious part of building this robot.
I can actually say, all work, including other
major modifications done to them including
to the hip section, easily resulted in 250+ hours
of work. Additionally, having legs
that bolt on, which makes them removable, was
critical to producing a high quality finish,
since
this enabled me to paint the legs and hip section
disassembled. The crotch area is far too
narrow to get in there with a spray gun without
causing paint runs. If the legs had been
permanently glued or fiberglassed to the hip, it
would have been impossible to paint them
correctly.
This is a straight on, front view underneath
the hip section,
inside the crotch area. The result of my labor was
fiberglass
legs that sit perfectly level and straight. After
the lips or contact points
were seated exactly how I wanted them, the vertical
side was completely
smoothed, detailed, and finished to appear as if
they originally came
out of the mold in this way, making the
modification completely
undetectable to someone unfamiliar with fiberglass
legs.
Additional internal fiberglassing was also
done knowing they were
going to have to support high amounts of weight
with future batteries
I had not yet purchased at that point. Either ICONS
or Classic Reborn
made a modification to their fiberglass legs in
this same area. I was never
able to figure out if their version was simply to
give fiberglass legs the
appearance of rubber or if they had similar
aesthetic issues.
I should also note that if these had been
rubber legs, this modification would
not have been required. Unfortunately, fiberglass
legs are completely unforgiving
since they don't flex like rubber.
A front view with the robot's right leg
section bolted on and his new
leg gasket attached to the base. Additional one
inch diameter holes were
drilled under the hip section to receive wiring
that will be run from the
charging port located on the rear of the soil
sample tread section side, up
through the legs, into the battery compartment
inside the hip section.
Several additional one inch diameter holes where
drilled as pass-throughs
for my leg attachment system that connects to my
upper knee plate from
inside the cavity of the hips.
The bottom section of the hip, where the legs
attach, is original, but required
a great deal of repair work and strengthening which
resulted in it being about 1/2"
thick internally in order to support the weight of
2 full size batteries. Everything
above that section was replaced due to severe
stress cracking that occurred prior to
them ever being installed on my robot. The cracking
was so severe, the
sections were deemed non-repairable
If you have fiberglass legs, be sure to
strengthen the top circular cutout area
where the waist plate sits and especially the
inside under portion. Originally, this
area was cast far too thin and flexible and is
where all your initial stress cracks
emanate. If left unchecked, moisture will work its
way into the fiberglass and
eventually you'll have stress cracks that will
reach out appearing like a road map,
down all four sides of the hip section, including
well into the zipper area. Some will
even cause raised areas and warping.
Regrettably, this is what happened to me
after initially detailing and painting
them nearly two years prior to the work you now see
on this page. I simply
placed them on several crates and covered them with
a tarp all that time. When
the steel tread sections arrived, it was time to
test fit them, and the surprise I
received when they were uncovered would not be
describable on this page.
Since fiberglass or rubber legs were no
longer offered at that time, I had no
choice but to begin work all over again and rebuild
these legs nearly from scratch.
Thanks to a 30 year old roll of Armstrong Armaflex
pipe insulation we had
left over from our central air conditioning
installation, I was able to match the
original diameter of the lobe sections perfectly
with little fussing. I used a
combination of Flint Mitchell's instructions and
techniques used by others.
A mold was then produced and a new fiberglass
hip section was created. A
great amount of detailing to the hip section was
needed to resculpt the zipper
front to back as it originally was. I later
regretted this, however,
I will be removing the zipper, front and back, on
these legs.
I've always wanted authentic rubber legs for our
robot and it appears if
I really want them, I'll have to make them myself.
The legs have been completed over a year now
and support a great deal of weight.
I'm happy to report there is no hint of stress
cracks.
