An alternative to the official Fireboard Nozzle Adaptor. This connects directly to the Fireboard Drive Blower's outer flange, securing it in place with its rails. I used a short piece of ¾" copper pipe I had lying around along with a copper elbow joint to direct the air downwards, under the charcoal grate.

1. Print
2. Remove the rails from the drive and attach to the slots in the adapter
3. Connect the fan to the rails, push in and tighten
4. Cut a 50-75mm (2-3") piece of ¾" or 19mm pipe (copper or something non-toxic when heated)
5. Push the pipe through one of the lower holes in one of the WSM bottom vents. I was able to slide the pipe through with a bit of persistence, but if necessary you can slightly reem out the vent hole by .5mm (1/64") wider in diameter.
6. Attach a 90-degree elbow to the pipe on the inside of the WSM and point downwards
7. Close off the other 3 vent holes. You can use high-temperature foil tape or ½" metal plugs (suggest avoiding brass due to the potential for zinc oxide problems if a brickette falls on it) if you're happy to reem out the holes a bit further.

If your BBQ temperature oscillates around your target temperature, ensure you have the air directed directly down with the elbow joint, as other directions can cause problems.

Printed in ASA for temperature resistance, but cooking low and slow I haven't seen the pipe get particularly hot so PETG would likely also be a good choice.

I printed this with a .4mm nozzle at 0.12mm layer height on a Bambu X1C - it doesn't need a fine layer height but I default to this and slower print speeds with ASA to help with warping. Minimal supports just for the top of the pipe hole, but it would likely print fine support-free.