I am going to do a YouTube short video tomorrow of the whistle. I will put it here when I publish it. I'll be blowing it on air.
Arnold, Material is steel (does anyone make these small cartridges from Brass? That would be awesome!) Not sure what size this is. It was actually a cylinder from my MicroNox torch.
Pretty easy to make. I actually made two yesterday but didn't like the 1st one. The thread for the valve is 1/4-40 ME thread. Could just as easily be 1/4-32. The hardest part was the little decorative acorn nut on the top.
Jim in Minnesota.