The cracks probably don't go all the way through to the inside of the horn and should just be considered surface cracks. They will probably not go any deeper with use of the horn. I would just give the horn a good paste waxing or apply beeswax and rub it in. If you blow into the spout of the horn you would be able to feel air coming out of the cracks if they go into the interior of the horn. If you are a smoker and blow smoke into the spout of the horn you will see smoke exiting the horn wherever there is a leak.
Sometimes boiling a horn, like in Rit dye, can cause delaminations of the horn to appear, but I believe the delaminations were already there before the dying and were just accentuated by the dying. Delaminations sometimes occur when the end grain of any part of the horn is subjected to a hot dye bath. I recently made a large F&I style lip horn and when dying the spout and throat area the raised ring between the spout and throat areas delaminated in several spots. On this horn the only fix I can see is to file the raised ring off the horn, redye the throat and spout area and install a separate band of horn and pin it onto the horn body.
Randy Hedden
