Just A Joke
If you live in Florida, use those ubiquitous sand spurs! Yikes! If the rocket manages to fire its ejection charge near the ground, you've got a bloomin' shotgun.
Also, they would do a number on the chute that flaming particles could only dream of, and for that matter, they woldn't do much to stop the hot stuff either.
Just A Joke
Serious:
Actually, it seems to me that for rcokets too small and/or cheap to be worth a real piston, one could use a sanded-to-fit slug of balsa and a lightweight braided metallic leader to hook it in. Simpler to do than a more elaborate piston, and light enough in small rockets. Probably ought to coat the bottom of the piston with something to protect the balsa, maybe a few layers of aluminum foil or flameproof wadding material glued in place.
Silly But Semi-Serious:
Now for something
really different. Y'know when your kids make those Jell-O wigglers? They make Jell-O, but use considerably less than the prescribed water. It comes out rubbery. It's still mostly water, but the pectin ties it together to the point that it's almost chewy. One could make those in molds the same diameter as the body tube, either in short peices or in a long cylinder to cut to length at the launch site. (Might have to dust the curved sides to get it to slide into the tube.) The only trick would be keeping them cool until launch time. Choose the colors for maximum visibility, and they double as a marker. I'm betting an inch or so of this would stop particles from most low-power motors.
The downsides, as I see them are:
1.) Weight. Jell-O, even when made really stiff, is mostly water.
2.) When ejected, it may melt and smear some, gradually soaking the tube.
3.) Ants. Most of what isn't water in Jell-O is sugar. The tubes will eventually get sticky and attract ants.
A final upside, though, is that Jell-O is biodegradable, water soluable (heck, when warm, it will melt on its own), and aesthetically and enviornmentally friendly.
I may try this on a scratch-built rocket some time. It might be good for a minimum diameter card stock rocket if the Jell-O slug is kept thin enough and the streamer is flame resistant crepe paper anyway.
Thoughts?
[Hmmm. Now you know why I call myself the Mad Rocketeer, I guess. ]