>When this happened to me it was because I was cutting a large core and using .011
>wire. What was occuring was the cutting wire was actually rotating very
>slightly back
>and forth as it went through the core. The melting foam would tug unevenly on the
>wire and rotate it a little one way then it would rotate back the other.
How could you tell the wire was rotating? Was this a direct observation or
an inference?
If uneven drag on the wire was causing rotation, what might have been
causing uneven drag on the wire? Could it have been bowing of the foam
because of internal stress relief? Could it have been caused by wire drag on
the templates? If it was caused by internal stress relief, a solution might
be to hold the foam blank in place with pressure applied through a foam pad
so that the foam behind the cut is bent into contact rather than allowing an
open kerf and a small ammount of uncontrolled foam movement.
The end
>result was a core with very small ripples as you describe. The ripples were worse
>towards the center of the core which would be another clue that this might be
>happenning. I switched to the normal stainless steel fishing leader wire and the
>problem was solved.
I use 0.02 monel metal fishing leader wire under about 50 pounds of tension
and have cut several dozen spyder foam cores mannualy without experiencing
the ripple problem.
This also happened when I was cutting up a large block
>of foam to
>make some core blanks. I was dropping a 52" bow through some foam with too thin a
>wire in use. Same weird ripples appeared. Again, using thicker wire solved
>it. I have
>not had this problem on less than 36" bows. On those I continue to use the
>.011 wire.
>
>Good luck,
>
>Dave Wenzlick
Regards, Ollie
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