Creating lasting outdoor art has challenged
humans since the dawn of time. One has only
to think of the pyramids (still there),
Stonehenge (mostly there), the Colossus of
Rhodes (long gone), or the Easter Island
monoliths (surviving, but then two heads are
better than one). In more recent times, there's
Mt. Rushmore, Stone Mountain Georgia, and
the Statue of Liberty. The goal is nothing less
than perpetuity. But of course, outdoor sculpture
needs to be done right or it won't last.
Making statues, i.e., permanent structures that
look like people, is particularly difficult.
One recent December, I received a call from a
fellow member of St. Luke's United Methodist
Church in Essexville, Michigan. St. Luke's was
attempting to deploy an outdoor nativity
scene composed of a number of life-like,
molded-fiberglass figurines. The problem was
that the shepherd figure was damaged and
could not take his watch.
The figurines were high-quality pieces with intricate
detailing, made by a local Christmas ornament
firm. However, while they had been
manufactured to very high artistic standards,
the figurines were structurally unsound for
outdoor use. The manufacturer provided no
means for anchoring them down. In previous
years, volunteers had simply attached each to
a plywood slab with big toggle bolts through a
thin bottom panel. They then spiked the slab
corners into the ground.
In due time, a typical Michigan winter froze
Shep to the earth as if cast in concrete. A hasty
post-season shove, intended to release him, instead
fractured the tenuous joint between the
sides of the pedestal and the bottom panel engaged
by the toggle bolts. Shep had broken off
all the way around the edges of his pedestal
(Photos 1 & 2). It was not a premeditated
crime. The charges were "baseless."
|1&2-Shep after being knocked off his base.|
I got the call because it was known at St.
Luke's that I work for an epoxy company.
(Few are aware that my specialty is testing
composite materials to destruction. I am much
more experienced at breaking structures, to
measure their strength, than at repairing
them.) However, I knew our knowledgeable
GBI technical staff might be able to devise a
repair strategy that I could handle.
It was clear that the base/pedestal joint needed
to be redone with WEST SYSTEM® epoxy. The
old polyester-encrusted base was discarded
and replaced with a sandwich composite panel
left over from past GBI test programs. I found
an undamaged two-foot-square panel with a
foam core and thick fiberglass face sheets.
In order to effect a rugged, epoxy bond to the
sandwich panel, it was imperative to take full
advantage of the generous surface area afforded
by the pedestal sides. GBI's Tom
Pawlak emphasized the need for good,
pre-bond surface preparation. He produced a
wire wheel tool with which to scuff the perimeter
to create fresh bonding surface (Photo 3).
Thus began a series of lunch-hour work sessions.
I kept at it until I got below the paint
and into the glass fibers. I cleared enough
width to accommodate a generous fillet of
filled epoxy. The plan was to go with WEST
SYSTEM 105/206 containing enough 407
Low-Density Filler to create a mayonnaise
consistency, ideal for filleting.
Before mixing the epoxy, I placed Shep on his
new base with the textured side up and traced
around the sides of the pedestal with a permanent
marker. Removing Shep, I had a guide
line that would permit me to trowel on filled
epoxy with enough precision so that the glue
could grip the inside of the pedestal as well as
the outside. The inside blind fillet would effectively
double the joint strength.
While I was tracing the perimeter, Tom had a
quietly brilliant suggestion: install a series of
stainless deck screws just inside the perimeter
line to be engulfed by the epoxy, further enhancing
the grip. It was done in minutes.
It was my idea to through-bolt the sandwich
faces in several areas to discourage the start of
a peel that might separate the upper joint face
from the foam core. For drainage of internal
moisture and condensation that might accumulate
in the field, I drilled a ¼" hole in the
middle of the base. I also drilled an ⅛" hole under each of Shep's elbows to allow air pressure
to release during bonding. These holes
would also allow equalization whether Shep
was on winter display or in summer
stand-down in a hot storage shed.
|4-A bead of thickened epoxy in the outline of the pedestal was applied to the new base.|
|5-After the pedestal was lowered onto the bead of epoxy, a large fillet was created around the exterior of the joint.|
To complete the surface preparation for bonding,
I used the wire wheel to abrade the textured
glass surface of the new base on either
side of the pedestal outline. We applied epoxy
to the base and to both the inside and outside
of Shep's pedestal rim (Photo 4). With the new
base face up on the workbench, we lowered
Shep into position and crafted the exterior fillet
|6-Shep (far right) was back on duty with twelve days to spare.|
The finishing touch was to coat the foam
edges of the new base with neat WEST
SYSTEM105/206. After an overnight cure,
Shep was ready to return to the St. Luke's.
Thanks to WEST SYSTEM epoxy, the complete
display was back on line, with still twelve days
to go before Christmas Eve (Photo 6).
W. D. Bertelsen is the
Chief Testing Engineer
at Gougeon Brothers.
This the first recorded
incidence of Bill not destroying
an object after
gluing it together.