Nick Kendall wrote:I am new to this but really like the idea you have using old stove as batch box had anyone else done this? I would like to try this but would insulate the riser as well
Yes. I've used a Charnwood Country 4 as the basis of a BB Rocket.
It's quite heavily modified though... To follow as closely as possible the dimensions on the Batchrocket Resources site, I had to cut off the rear of the stove and extend the depth of the firebox. The whole of the original stove is heavily insulated with insulating firebricks and superwool - there is no metal from the original stove (apart from the cast iron door) that is in contact with the fire. It's a 5" sidewinder system that I use to heat water and a brick bell. It works really well and is into its second winter with only a few issues.