Hello Craig,

I have experience with both Howe Fill and Howe Film from approximately 2-3
years ago.  I had a metal core board of .060 thick CIC and used the Fill
successfully in low volume production.  The Film product was used in some
quantity of prototype.  They are both Polyimide resin with ceramic particles,
the Film has a cloth structure (i.e., Polyimide or FR4) where the Fill has
none. The Fill is literally sprinkled onto the surface.  Both products
allowed two multilayer subs to be laminated without additional CIC core hole
fill processing.  Both products -like all the Arlon materials- are excellent.
 The Film is widely used for the CIC foil (thickness of <.010) while the fill
is used on the thicker cores.  The construction is expensive and the two
materials and associated processes are (appropriate) adders.  Thermount
material has put a huge dent in the metal constraining core product and the
future existence of the Howe Film and Fill, as well as metal cores such as
CIC is in question.  
I will say that the HoweFill succeeded where other materials failed.  The
name "Howe" is derived from a most excellent fellow whom unfortunately was
lost in an automobile accident.  Art Howe did much for PWB industry and
excelled in the Polyimides.
Feel free to give me a buzz; 781 858 0783... [log in to unmask]

Best regards,
Coretec Brad