These bubbles are actually hollow glass
spheres. Because this high-quality glass is very crush resistant, the foam
is much stronger, stiffer and water-resistant than any foam made by chemical
foaming. These foams displace 4-6 times their weight in most resins and
improve the handling characteristics of the base resin. They have a low
bulk density and are nontoxic. Mix resin and hardener as directed, then
fold in the glass bubbles. Upon cure, a strong, low-density product results
which is easy to sand and file. May be shaped to form compound angles and
curves. The term "micro" was applied to the mixture of microspheres
and epoxy early in the development of composite structures. Although microspheres
have been replaced by glass bubbles the word "micro" is still
commonly used to reference the mixture. "Micro is used to fill voids
and low areas, to glue foam blocks together and as a bond between foams
and glass cloth. Micro is used in three consistencies - (1) a "slurry"
which is a one-to-one by volume mix of epoxy and glass bubbles, (2) "wet
micro" which is about two to four parts glass bubbles by volume to
one part epoxy, and (3) "dry micro" which is a mix of epoxy with
enough glass bubbles to obtain a paste which will not sag or run (about
five parts to one by volume). In all instances, glass bubbles are added
to completely mixed epoxy resin and hardener. Wet micro is used to join
foam blocks and is much thicker than slurry (it has the consistency of honey)
but can be brushed. Dry micro is used to fill low spots and voids and is
mixed so that it is a dry paste and will not sag. Apply with a putty knife.
Never use micro between glass layers. |
| CAUTION - When mixing epoxy and glass bubbles, wear a
dust mask and keep your face away from the balloons that may
float up into the air. Although glass balloons are inert, they
can lodge in your eyes or in your lungs and cause problems. Handle
with care. |
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