Gary Caron saw  "... a Millers Falls plane.  A
second look cured me of that notion.  This one has (had)
red plastic handles.  So, how do you get a handle to look like this?"

http://i1358.photobucket.com/albums/q780/gctool/20140823_085130_zpsef11
ec0d.jpg">http://i1358.photobucket.com/albums/q780/gctool/20140823_085130_zpsef1
1ec0d.jpg



Looks like standard plastic decay to me; basically self-generated, though it can
be accelerated by environment.

Plastics are very diverse, and I don't know which one was used by Millers'
Falls. However, the oldest and most common was cellulose nitrate (celluloid),
and Ricky Jay  published a fascinating book on the decay of his collection of
cellulose nitrate dice.

http://www.amazon.com/Dice-Deception-Fate-Rotten-
Luck/dp/1593720300">http://www.amazon.com/Dice-Deception-Fate-Rotten-
Luck/dp/1593720300
http://www
.npr.org/templates/story/story.php?storyId=893954

Some of the information is to be found on the Museum of Jurassic Technology
website, though my memory of the book is much more vivid than what is on the
website:

http://www.mjt.org/exhi
bits/rickyjay/rjay.html
http://www.mjt.org/exh
ibits/rickyjay/rjay2.html

Jay's dice are mostly celluloid, which dates back to the 1860s. Although I doubt
celluloid would have been up-to-date enough for Millers Falls, its manner of
decay is similar to a number of other plastics, and gross symptoms of the decay
can be similar. Celluloid is a physical mixture of cellulose nitrate (also known
as guncotton, the dominant high explosive of WWI) and camphor as plasticizer.
Over time the camphor evaporates out of the celluloid, causing it to shrink and
get brittle. The cellulose nitrate polymer breaks down, and in breaking down
releases nitric acid, which accelerates the breakdown, sometimes explosively.
Later plastics used less volatile plasticizers for a physical mixture, or
actually used an "internally plasticized copolymer" where the polumer chain is
runs of the plasticizer alternating with runs of the basic polymer. And later
plastics used polymers that broke down less quickly and less explosively than
cellulose nitrate. Even so,
 many plastics are similar to celluloid in make-up, decay, and physical symptoms
of decay. If I had to make a guess I would say that MF handles are most likely
cellulose acetate, which breaks down a lot like celluloid only slower, but this
is a long way from my real competence and I'm pretty much guessing there.

Tom Conroy