Humidity Quick Zap

[Bill Ballard]

At 5:56 AM -0800 12/14/02, Keith Roberts wrote:
>The analogy I heard about felt was that it is similar to Chinese handcuffs.
>You know, the braided tube you put your fingers in and they can't back out.
>The wool fibers are the same way. Once interlocked, movement will cause the
>fibers to tighten. *Swelling and shrinking (from moisture changes)
>constitutes movement.*

I'll agree that the fiber platelets' interlocking process is 
primarily one-way. It's a mechanical matter.

>Rapid movement and the fibers grab, slow movement
>and the fibers can slip back closer to their original state.

The behavior of Chinese handcuffs is well understood. However the 
finger's motion is axial not rotational. Not only is the centerpin's 
motion rotational,, but it's net is always zero (shanks starts at the 
rest rail and returns there).

>Perhaps this is why wool garments shrink in the dryer.
>
>The other statement I heard and haven't been able to elicit an explanation
>to clarify, was, *Alcohol changes the chemical make-up of the felt.*

I'd be surprised to find that out.

>Perhaps the lanolin (I think it is the natural sheep oil found in wool),
>gets washed out, leaving a *dryer* felt. Any chemists out there who would
>know if there is an actual chemical reaction from the alcohol?

We had one on the list once: "Earl Dunlap, Textile Chemist and 
lurker". You can check the archives for his description of how 
acetone works on felt (if Susan Kline doesn't re-enter it a second 
time).

>At 8:10 AM -0700 7/22/02, Susan Kline quoted you:
>>By the way, any of these alcohols are very water soluble (as is acetone
>>(very much more volatile & thus more flammable) or methyl ethyl ketone (a
>>bit less so)), and when they evaporate rapidly, will chill the area drawing
>>moisture from the air--more so in humid climates. This moisture has the
>>potential to release the press in the wool! (Re: Susan Kline's correct
>>"steam in a bottle" comment on 04 Sep 2001 18:30:15)
>>
>>Earl Dunlap, Textile Chemist and lurker (with your kind permission)

David Stanwood and his wife have actually owned sheep. He's got 
plenty of "vertically oriented" knowledge.

I'm overdue on my morning oatmeal.

Bill Ballard RPT
NH Chapter, P.T.G.

"I gotta go ta woik...."
     ...........Ian Shoales, Duck's Breath Mystery Theater
+++++++++++++++++++++