I’ve owned a number of these flutes over the years,
and treated them, well, roughly. But none
have cracked or broken or…
I’m thinking of the 300 dollar variety.
Short of jumping up and down on these,
does anybody know of a
Sweetheart flute that has cracked in
ordinary use, e.g. due to dryness?
Are Sweetheart flutes indestructible?
No.
http://ircamera.as.arizona.edu/NatSci102/images/mush.gif
Have you tried it? 
OK. OK, if I want to play a jig during a nuclear holocaust,
I’ll reach for delrin.
Actually, I think Delrin would melt.
But until just recently I owned 6 of Ralph’s instruments: two whistles, two fifes, a flute, and a tabor pipe. Except for the flute, all of these are about 15 years old. While you do have to give them all the normal care of a good wooden instrument, I never had even the suspicion of a problem in all that time, and they never required any special care at all. One of the whistles is my primary, and it just won’t quit. I’ve had to re-cork it twice in all that time, and oil it once in a while, but never any trouble at all.
I think the two important things about them, at least the kind we’re talking about, is that they have fairly thick wood at the joints, and there are no metal liners. Those are the spots where most flutes develop cracks, I believe.
LOL!!!
and I’ll bring the marshmallows!
mmmmmmmmmmm: crispy!
M
Actually, I think Delrin would melt. eek
And I would precede it!
How about this thought. If you want a rough and
ready flute, to take hiking or whatever
or to go places and/or that sort of thing,
the stuff we often think a delrin flute
does best, the sweetheart (while perhaps not
so robust) is a good bet.
Above all these are disinclined to crack
in dry environments.
I’m not suggesting madness, like applying humungous
pressure or leaving it a car in July in Arizona,
but still a good travel flute.
Nobody can report a crack, apparently.
Sorry Jim! 
I received a used Sweet rosewood folk fife that cracked during transit. It was shipped during an extream cold spell (windchill was about -25 celcius here) and it came from central Michigan where it was even colder. The parcel was well wrapped and in good order upon arrival. So I believe the extream cold was the culprit and simply “freeze dried” the fife and cracked the head. 
I personally feel the most injurious thing I subject my flutes to is their transit through the postal system! 
I think they would make excellent backpacking flutes, certainly the keyless models would. If you oiled it before you left home and had a nice padded case for it, like the kind of thing Annie makes, I wouldn’t see any problem at all. I suppose if something REALLY heavy fell on your pack, well…
I’d be more suspicious of the extreme cold than any kind of ‘freeze-drying’ effect. The whole idea behind oiling a wooden flute is to keep excess moisture out while keeping just the right amount in. In such brutal cold, and being exposed for several days in transit, it’s likely that the flute simply froze through and became very brittle. The wood may have contracted to an extreme degree, or the instrument may have taken a sudden blow while frozen. Any sudden thermal shock, such as opening the package before the contents have reached room temperature could theoretically cause a crack also. I recieved a dulcimer shipped in early December (not extreme weather here) and the box had a label warning the recipient to allow several hours for the whole thing to warm up slowly before opening. It wasn’t necessary in my case, but sound advice. The fact that water expands when it freezes is another possibility.
Transit conditionas are often the hardest thing we do to a flute, as you said. Personally, I would never ship any musical instrument under those conditions. Just too risky for my thinking. No matter the absolute cause, I would think that exposing a flute to such severe temperatures is a recipe for disaster.
More like sublimate or turn into a plasma, depending on your proximity to the blast zone. Well at least your flute would project.
That’s really taking overblowing to the next level.
Mmmmm. But would it be harmonious? (Or sweet? 
)
If we are contemplating being sublimated, evaporated or otherwise atomised, does atomic weight relate to the harmonic series, mathematically, that is? A sublime and weighty question, if a trifle overblown. 
Jim, why do you ask this specifically about Sweet flutes? Any hardwood flute that has no metal should last forever. There is no more reason for a flute to crack than anything else made of wood, including table legs. It seems to me that nothing short of extreme abuse would cause a keyless flute with no metal lining to crack.
Do you consider having a flute roll off of a pub table or an inattentive player’s lap to be “extreme abuse”? Because I know of more than one player who has had this happen to their keyless flute, and the flute ended up cracked. I need to know whether or not to report these people to the flute abuse authorities.
Yes, although I would expect the flute to break at the tenon rather than develop a crack along the shaft. Flutes made of proper wood should be capable of being dropped to a hard floor for a height of three or four feet without cracking, but I don’t suggest testing the theory. Dropping any instrument qualifies as abuse, however, even though it may be accidental.
I was once accused of ‘flute abuse’ by a well-respected maker,
after the flute he made for me cracked. He said none of
his flutes had cracked in years and he threatened not to
honor the warranty.
This was a dark moment, I promise you.
Me, a flute abuser! I believed it too.
I abuse chickens, etc. Why not flutes?
Later, when he saw the crack, he
told me I wasn’t responsible. It was a flaw in the wood.
I took off the hair shirt and put the bed of nails
back in the closet.
But I still wake in the night screaming.
It may be that any all wood flute is very unlikely to
crack. However my chief concern is dryness and
humidity change, and
I don’t see why all wood flutes should be invulnerable
(though I appreciate why they would be less vulnerable
than flutes with lined heads). After all these are hollow
tubes, not table legs, The latter are filled in all the way
through.
The Sweet flutes are soaked maybe three times in
tung oil so that they won’t absorb much moisture.
And I suppose this works the other way. They
may not expell much moisture either. In effect
the wood is sealed. So I thought perhaps this
made them specially resistant to changes in
humidity, my chief fear.
I sometimes travel in New Mexico and other dry places,
and I wondered if a Sweetheart flute would
be the best bet to survive with minimal attention
in that sort of dry
climate.
Hey Jim,
It is my understanding that Sweetheart flutes are not just soaked in the tung oil, but treated with it by pressure and heat. They are impregnated with the oil.
It has been my experience that this does make them very stable! 
I also think that it enhances the tone and playability of their softer wood flutes (maple, walnut, apple and cherry).
I also have one of their Resonance flutes made out of the laminated wood. It has a warm woody feel to it, yet is stable and nearly impervious to moisture. I much prefer it to Delrin. Though Delrin does tend to produce a darker tone (IMO).
I didn’t know about pressure treating, but I knew Ralph soaked them extensively in tung oil. The ones I just sold always looked to me like they were polyurethane coated or something. Very shiny and hard, ultra water-repelent. My other flutes don’t look like that, only the Sweets.