This article is from the Model Rockets FAQ, by Wolfram von Kiparski with numerous contributions by others.
From Jeff Vincent:
>... but WHERE do you put the stuff? In the ejection charge or in a
Conventional wisdom is to just dump it in, between the wadding and the
recovery device (that way when you see the cloud, you know your 'chute
is out, even if you can't see it). As you get into smaller models
(18mm tube diameter or smaller), skin friction (with the inner tube
wall) starts to become a problem.
My practice is to make a small pouch with the old MRC wadding
(consistency is similar to silkspan). You will form the pouch around a
dowel just a bit smaller than the tube ID. Cut a piece wide enough to
make just over one revolution around the tube. Wrap the wadding around
the dowel, fold over the bottom end, slide it most of the way into the
body tube, *then* remove the dowel. While holding onto the top edge of
the pouch, fill it with tracking powder. Once full, crimp/twist the
upper end shut, drop into the tube, and load your recovery device.