I have an old rosewood flute (Late 1800’s I think) with a couple of serious crack in the barrel and head. I do not want to put mcuh money into the flute as I don’t believe it is worth. The flute does play. What is the best way to fix these cracks barring a flute restorer.
Cheers from the Ennis Trad Festival:)
I know nothing about antique flutes, but if I were in your position I’d do nothing to the flute until I knew more about its value. Post a few pictures here, and you’re likely to get some informed opinions.
I’ll second crookedtune on the pics. I do these kinds of repairs, but you almost certainly have people who can do it for you closer by. It isn’t impossible to DIY if you are handy and willing to take a risk (that’s how I got into it!), but do check out what you are risking first, and if it is anything valuable, get an experienced specialist onto it. Once you’ve checked that out, I’m sure we can give you some tips on the forum if you decide to try yourself. First steps = post some pics - of the whole flute and close-ups of the damage.
Poor schmuck. 
From personal experience (and those more knowledgable, please chime in), I have learned that, if you seal the cracks from the outside, you may solve the air-leak problem, but the crack may very well be wider on the inside. Even though air no longer leaks, it is my theory that the inside fissure is a haven for moisture that will cause your tone to become gurgly after you’ve played for awhile. At least, that was what I experienced when I fixed some cracks myself. When I had a pro work on it, the gurgly problem vanished, except for the usual collection of moisture that must be periodically blown out.
The other advantage to a pro is that the repairs are virtually invisible, which may not be a concern for you if you don’t highly value your flute.
Cheers.
Picking up on Cubitt’s post, although (due to their radial nature) they are not likely to be wider on the inside, he is right that filling them on the surface will likely leave a still open interior crack which, if in a place where water condensing in the bore can get into it, will indeed just swell and crack again. The majority of cracks, however, occur in metal lined head and barrels, and as such the access of moisture to them from inside is very limited. The filler itself can also serve to force the crack wider. Filling them is NOT the thing to do as it doesn’t solve the underlying stress problem and is also bad cosmetically. I’d go so far as to say cracks should never be filled, and certainly not as the main or sole aspect of a repair.
The optimum repair on lined sections is to remove the liner tube, clean the crack, glue and clamp it closed, then re-ream the bore to readmit the liner without stress and glue that back in. Any surface crack remaining can be filled with a (self) wood dust and glue mixture as a top dressing and then sanded and polished to match the surface finish, thus rendering it very difficult to see. In some instances it may be advisable to insert metal screw-pins on chord lines in the thickness of the wood to draw a crack together, but that is a less popular repair now than it used to be. The pin heads are countersunk and hidden with the same top-dressing technique. It is more likely to be necessary in unlined body sections where the cause of the crack is more likely to be due to a fault in the wood than to stresses like those affecting lined joints. Obviously greater care would be needed in sealing the bore-side surface finish of a crack in an unlined joint as it would be exposed directly to moisture.
I agree that the best way to repair the crack, would be to pull the liner on the head and barrel. I have found that if it is done right, pinning or whipping is not necessary. Once the pressure is relieved in the head joint, the crack seldom re-opens. My latest technique is to use a heated rod on my lathe, and press the head joint off the liner. The barrel liner is pressed out also. This is a little more tricky, as the slide is often locked in, where the inner liner has a flange inside by the socket, and a silver sleeve pressed on the outside of the slide. Sometimes the wood is sandwiched between these pieces! A rubits cube…
Late 1900s, shurely. If it’s a century older, it’s worth a good deal more.