Hammer Steaming/Felt facts

stanwood stanwood@tiac.net
Wed, 08 Nov 1995 14:27:44 -0500


A general reply to all the discussion on Hammer Steaming:


The beauty of the wool fibers in felt is that they want to stand up
straight, as if on the back of a sheep.

The intertangling of the felting process restricts the movement of the
fibers and they can't stand up as staight as they would like.  They try, but
can only get so far.  This leaves air spaces in between the fibers.  The
amount of air space determines how much the fibers can flex as the felt is
compressed (as in a hammer strike).

The ability of the fibers to push back after flexing is a function of the
very complex molecular structure of the wool fiber.  Essentially each fiber
is a bundle of little rubber bands.  Flexing and moving back and forth
relates "resiliancy".  Resiliancy is erased by pressing with dry heat.  The
heat softens the wool fiber by virtue of its thermoplastic property and the
pressing reduces the air spaces making the felt become denser and less
resiliant.  When the pressure is released and the felt cools, it remains in
this densified state.

Two things will restore the resiliancy of the wool fibers pressed with heat.
Heat in combination with water, and physical working and moving the fibers.

Techniques such as steaming and adding alchohol/water to felt restore the
resiliancy if the felt was hot pressed and if the fibers have latent
resiliancy locked up in thier structure.  It's the water that activates the
wool.

I like steam because it introduces a minimal amount of water that drys in a
matter of minutes.  If you overdo the steam, file off the soft felt.  If
needed, use needles after steaming to soften deeper layers.  The steam
expands the surface layers first and allows room for deeper layers to expand
and make the air spaces larger buy needling.

This is all the time I can devote to writing today, gotta go to work.

David C. Stanwood
















If there is integrity of the molecular structure of the wool fibers.



For wool fibers in felt to act resiliant there must be space for them to
move in.

Resiliancy in felt is degraded when the complex chemical structure of the
fiber begins to break down.  This break down is brought on by a number of
factors.  Excessive heat, degrades the fiber structure, espcially when above
200f.     in the resiliancy of the wool fiber



Wool has a semi plastic quality.




  When dry felt is subjected to dry




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