This article is from the Model Rockets FAQ, by Wolfram von Kiparski with numerous contributions by others.
From: firstname.lastname@example.org (Doug Wade)
[concerning adapting launch controllers to 12V car batteries ...]
Speaking of which, I took my Aerotech launch setup, lopped off the
igniter attachment, and the place where it attaches to the battery, put
amp plugs on either end, put a plug on the battery, and made some
alligator clips in various configurations for launching Estes stuff.
This means that I can switch batteries and igniter style in basically
no time at all. It's not a lot of work, and it makes life easier. If
you have the urge to do this kind of thing, make sure that you get
plugs that can handle it. A 12V motorcycle battery (Mine was about
$40 but it's pretty nice) can put out something like 15A for a short
period of time...
From: email@example.com C.D. Tavares
[concerning an ongoing discussion about blast deflectors]
I've had first hand experiences with several types of metals. I've never
found a piece of aluminum that was worth dog-doo as a deflector. In the
higher engine ranges, even steel will give you problems, especially with
maintenance. Stainless isn't much help, since it still cruds up.
What we use are discarded grinding wheels. Fireproof, non-conductive,
free, plentiful, large, and pre-drilled. The only negative on these is
that when an engine catos they tend to lose large chunks or crack in
half. This happens to us maybe three times per year, but as I say,
they're free and they're plentiful.
From: firstname.lastname@example.org (Bob Kaplow)
Use clay flower pots for blast deflectors. Get Stainless steel for
launch rods from welding or metal supply houses.