Posted for daniel newland <compositeguy@sbcglobal.net>:

 Pure micro is always a bear to work with.  I always use a mixture of micro
and fumed silics (like Cab-O-sil).  Micro is lousy as a thixotrope.  If you
add enough to where it will hang vertically, it is so viscous as to be
unspreadable almost.  Very "dough-y".  Cab-O-Sil is a lot harder and if used
as the only thixotrope, is like vasoline and kind of elastic, i.e. when
spread, it pulls a bit then rebounds.  But if you mix about 25% Cabo with
balloons, it spreads and hangs MUCH better.  If you really want a creamy easy
to spread mix, add about 75% Cabo and 25% balloons (by volume).
 
 Dan Newland