>>some one has tried just spreading micro balloons in the fabric
during the layup process while the epoxy is still wet.<<
I don't think that's a good idea because diluting the resin in any way will
weaken the bond with the glass and reduce the compression strength unless you
use a high strength filler. I prefer to be able to inspect the layup properly
after cure. If you simultaneously fill you won't spot any bubbles or
delamination.
The best solution I know is to use 15% or so of "Cabosil" colloidal silica mixed
in with the filler. It gives a vast improvement in spreadability and reduces the
number of pinholes. I suspect it reduces the surface tension of the resin and
helps it's wetability. Whatever, believe me it WORKS. It has no effect on
sandability. In fact my experience is that you can add about 25% more filler and
it still spreads easily.
The other real time saver is Ron Swindens thick fishing lines.
Graham
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