Just a quick note. It is legal to buy, sell and use Halon for any purpose in the USA. The Halon 1211-1301 blend units sold by H3R ARE for Aviation Use Only, but H3R also sells straight 1211 units online (http://www.h3r.com/products/home_vehicle.htm).

Halon is twice as powerful as the Halon alternative Halotron, and it is less expensive. Unlike C02, there is no danger of "cold shocking" electronics.

What is more, Halon is remarkably safe, as well as extremely effective. This is why it is required for commercial aircraft use.

As for dry chem extinguishers, I have heard of entire aircraft having to be scrapped due to corrosion from the powder after relatively minor fires.