I’ve made three oaks tuneable, with varying degrees of difficulty. The first one I just kept twisting at the head in idle moments until it started shifting… and eventually it moved noticeably, and I wormed it off by main force, and then simply put it back on, and continued tuning it by main force whenever I needed too… result: slight scalloping on the inside of the head where the end of the body has scraped the inside of the whistle-head… further damage has been prevented by applying cork grease (meant for flute joints, but hey…)
The second one was much more adamant about not moving; I made it tuneable by running hot water through the body until it was nice and steamy, and then stepped on the head and pulled on the body… ker-pop! Some scraping on the surface of the head, but the tunnel is lacking the scalloping of the first try; sound is perfect.
The last one I did by dipping in microwaved hot-water… it immediately drooped, and I panickedly reshaped it. I recommend, if you use hot water… use it from the tap to limit the upper temperature.
Fortunately, the distortion was minimal, and by holding the breath-tunnel straight, it cooled back into its original shape… the blade, etc, seemed unaffected. I then, once it was reasonably hard again, wrapped it in a dish towel and used pliers on it. I grasped the round part where it joins the whistle, and, to appearances succeeded only in putting plier-marks in the plastic even through the dish-towel… but then a hand twist popped it off. Conclusion: I was both loosening the joint, -and- holding it in place by squeezing down on the part that is over the body… if you use a pliers or other ‘gripper’ method, apply the force to the flattish walls on either side of the fipple blade.
Anyway, all experiments have resulted in success with only minor cosmetic damage; apply some sort of grease (slide grease, cork grease, whatever) or a tightly-fitting headpiece will be pratically as hard to remove the second time as the first (those experiences omitted to make me look less stupid… I mean, uh, that didn’t happen to me, but I’ve heard… err, yeah.
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Ideally, I’d use padded pliers that are designed to be padded pliers…
Also, I highly recommend washing your oak out with hot tap water from time to time anyway, even if you’re not going to be loosening the head right then… it vastly improves ‘spit-clog’ problems. Remember to re-grease after every few washings because some of the grease will get washed out (not much, but a little each time…)
–ChrisA, and his Oak. 