[CAUT] Vs Profelt... again

[Fred Sturm]

On Dec 18, 2008, at 9:58 AM, David Skolnik wrote:

> .like, what the solids are in VS,

Best I can tell, from evaporating some, is that the residue of VSP is  
silicone oil and conditioner (the fabric softener used in laundry). I  
also evaporated some fabric softener, and it seemed like the residue,  
plus some oil, matched pretty well.

> and how that would make it more of a sizing solution than a  
> shrinking agent.


With wool felt, water is the agent, both for "shrinking" and "sizing."
	Shrinking is essentially making a denser felt, interweaving the  
fibers more tightly. If the felt is being compressed or agitated while  
wet, it will "shrink" (especially noticeable when a wool sweater is  
put in a washing machine, but also with pinned action centers).
	"Sizing" in the sense of making it "larger again" is a matter of  
making a less dense felt. If you add water and have no compression or  
agitation, the fibers will tend to unlock somewhat from one another,  
especially if they are densely held together and there is a kind of  
pent up pressure, resulting in a less dense felt that takes up more  
volume.

	In either case, the water and the individual fibers are interacting  
identically, with the fibers swelling and their scales standing up a  
bit.
	The conditioner is essentially only affecting electrostatic charge,  
best I can figure out (they are usually "cationic"). I don't know if  
this has an affect on felting or not. My guess is that it doesn't  
affect felting much if at all, but I certainly could be wrong there.   
It does reduce friction, but because of surface electric charge, not  
as a lubricant.

Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu