i'm going to try it on a 10 gallon i have laying around. i'm going to find something cut or dead on the side of the road, soak it, bake it, soak it again... and test it on some guppies.
local firewood? .. should be able to find some nice hardwood from a local firewood dealer. most firewood, particularly for smoking purposes needs to be weathered at least 1 season.. or more. getting some nice branches shouldn't be to hard if you have some time to dig threw the scrap pile. You'll still have to bake and soak.. but should be cheap.
I agree with whoever mentioned Manzaman. I'm in the middle of a transaction with him and he seems like a good dude. His prices are hard to beat and he has some killer pieces. Depending on where you are you might even be able to set up a local pickup and save on shipping.
