Thanks Wayne, it was just a bit of fun but worked out well enough.
As there's no more new videos on here yet I have included one of my previously completed project which is a vertical boiler incorporating cross tubes in the flue for better efficiency, it is made using a vintage jet engine starter cartridge of some 3 inches diameter, shown here with a Cotswold Heritage Perseus engine and heated with a 1 inch Bix gas burner:
Dave