Well, it's been another period of no posts. I seem to go in spurts like that, sharing what's going on and then focusing on actually doing things, and not communicating about it. But I'm like that I suppose. My wife says when I get interested in something I focus on it.
I have not made any real progress on the black whistles because while the mandrel approach does work, it is somewhat unpredictable. Maybe it's lack of practice on my part, but sometimes I get a nice looking mouthpiece and sometimes I wrinkle it as I'm trying to get it to slip over the mandrel. I think it's due in part to the mandrel not being heated and cooling the part before it's fully expanded, causing it to bind. I may try making a mandrel with passages for the hot air so I can keep the mandrel warm from the inside and possibly improve the repeatability of the forming.
But, then how to get the parts off and allow them to cool? The seem to do best when allowed to cool on the mandrel, but this will mean each mouthpiece will take a LONG time to make compared to turning and parting on the lathe. The temperature of the shop compared to the temperature of the mandrel causes varying amounts of shrinking while the part cools off the mandrel.
So this is the main technical hurdle at the moment. The other reason for a lack of progress on the black whistles is the need to make white whistles for customer and dealer orders for the holidays. At one point I had a backlog of over 100 whistles, not counting multiple bodies for most of those. I'm not complaining! But I believe existing orders come before R&D, so not much R&D has been done.
But with the holidays past I'm about to catch up - in fact I hope to ship all outstanding orders today, or at least have them ready to ship tomorrow. And then I'll get back on the black whistle project, and hopefully let you know how it's going from time to time. Maybe I'll set a reminder in my things to do to prompt me to post....