Re: ATM Pitch Laps

[mdholm@telerama.com]

The first time out, it isn't a bad idea to refrain from too many new ideas.  
The chances are high that you will find polishing and figuring somewhat 
challenging.  Keeping reasonably close to the paths that others have trod 
makes it much easier for others to give helpful advice and for you to compare 
your experiences with those recorded in (dare I say it) books.

Adding small particle size solids to the pitch will tend to make it behave in 
a more viscous and more ridgid fashion.  That may be good or bad depending on 
circumstances.  I seem to remember reading about people adding sawdust to 
pitch in order to bring up the viscosity when the work had to be done in very 
hot circumstances. (It would not be my choice.)

Another truth is that it is difficult to evenly disperse fine particle size 
solids in a viscous fluid.  Even hot pitch is pretty viscous, and heating it 
hot enough to lower the viscosity a lot isn't good for it.  Vigourous stirring 
is likely to stir in air too.  Unevenly distributed CeO in the pitch could 
lead to any number of headaches.

Mark Holm
mdholm@telerama.com