Among those whistles I’m getting organized to sell is D C set by Steve Harper. They are aluminum. The head is “bonded” to the D body. I’ve tried most of the ways I know to break the bond with no luck. Any help here? They are lovely engraved whistles and I’d like to make them useful again.
Thanks.
Yes, that can be a problem. Aluminum on aluminum joints can be buggers to loosen once they’ve seized together.
You might want to contact a local wind instrument repair technician. They’ve like seen stuck flutes and horns and have methods and tools to apply to the problem.
Still if you want to have a go yourself what I would try first is to wrap the parts in a rubber gripper like those used to open stuck jar lids. I have sheets of rubber sold as shelf/drawer iners in the shop that work well for this. Anyway it just helps you hold on to the parts to assist with pulling/twisting them apart. Still the improved grip may be enough to move things.
Then I would try the “deep freeze” method. Place the whistle in the freezer for an hour or two. Aluminum will shrink when cold. The parts may shrink enough to come apart or loosen the oxide between them a bit. Use the rubber grips as above. Commercial enterprises with similar issues use dry ice to hasten the process, or so I have been told.
Heat will work in some cases as well. Be conservative with the heat though. Don’t go melting things. I’ve had better luck with freezing than heating aluminum. I have used heat to break bonds between aluminum bike parts with success but in those cases the heat was actually melting some type of dried up lubricant that was assisting with the seizure.
Ok, two more methods from the bicycle world com to mind. Amonia is supposed to help break down an aluminum oxide build-up if that is the cause of the seizure. That’s been used to un-stick an aluminum seatpost in aluminum bike frames. I think amonia wll also discolor uncoated aluminum. Some have claimed success using vinegar to do the same. Worst case in my arsenal would be to try brake fluid. I believe it will also break down aluminum oxide. Too much, too long could cause pitting in the aluminum as well. I have never used that on a whistle, procede with caution and at your own risk. Might want to do some reading before you try these.
One issue I can relate from the bicycle world as well is that when two aluminum parts bond the area where the parts bond together can distort where the oxide layer has formed so that a smooth sliding of the parts in and out of each other is no longer achievable. I would hope that is not the case with the whistle since it should not have been exposed to the type of environment that a bicycle might.
Hope that helps.
Feadoggie
I like the freezer method. My experience from the sheet metal shop introduced me to using liquid nitrogen. . . 
However, before I used any ‘home’ remedies I would make a trip to an industrial hardware/supply store and get one of the whiz-bang bolt remover type solutions. I like ‘Bolt-Breaker’. Croil is another. Boeing has a proprietary spray-on that is sometimes available. Feadoggie is right in that the problem is Aluminum Oxide.
What I would try first would be several rounds or cycles of the following. You will need the ‘grippers’ Feadoggie has advised.
Apply your penetrating/anti seizure oil. Freeze the tubes. Then using a cloth soaked in warm water, grip the ‘outer’ tube, grip the lower tube and twist. The first time may not work (or the nth time. . .). Tap the tubes while re-applying your magical potion of choice. Re-freeze, rinse,shampoo.
The patent penetrators will dissolve a little of the oxide each cycle. Tapping helps it creep into the interstices A little at a time is the answer.
A week of this routine should show some progress and not scar the tubes. If not, then punt it to a technician.
Best of Luck,
Bob
My suggestion would be to avoid the potential for damage and sell the whistles as is. Let the new owner make the decision on how they want to proceed, depending on how risk tolerant they are.
That said, with brass, silver and nickel whistles, rapping the stuck area with a rawhide mallet is usually the way to go. Aluminum however I’m not so sure about this method.
I’d like to second the comments on freezing.
Further, you could try combining the freezing with hot water. Specifically:
I hope you let us know how you finally decide to proceed.
Good luck !
trill
Not sure if it will make a difference in getting the whistle unstuck, but I thought Steve Harper made his whistles from sterling silver.
Mike
Perhaps he has. I looked at te Harper Classic website and there was no mention of a material as far as I could see. The Harper Classic page on Facebook seems to have vanished, so no help there. I do know Harper has made a couple types of whistles though. Just looking now at the little marketing blurb for a C/D set at the Whistle Shop I read this.
The C&F guide to Expensive Whistles, which I always assume to be the most authoritative and accurate site in whistlesdom ( 
), describes the Harper like this.
As Loren said, proceed with caution. You achieve the same thing by heating the whole whistle slowly then cooling the male part quickly as cooling the whole whistle and heating the female part quickly.
Harper whistles’ fipple blocks are just held in with adhesive. I’d recommend not doing the sudden temperature change on the head, as this could dislodge the fipple. I can’t remember whether the head is the male or female part of his whistles. But if it’s the female part, I’d suggest heating the whistle slowly (to maybe 90C/ 200F) then plunging the body into ice water and pulling apart as directed above.