I wouldnt really reccomend welding, soldering or using epoxy or anything of that sort as solder or welding can break and epoxy is just nasty.
I would reccomend drilling however thier is a slight risk that the crack will continue if you fail to drill correctlly, you can however maxmise your chances of ending the crack.
I did this to my ride cymbal and im waiting a week or so to determine results. All you need is some flour (Baking flour preferably) and some wd40.
Spray some wd40 onto the underside of your cymbal where the crack is (in your case the bell) and rub it in really good, until the surface of it is dry but slippery wipe any excess. Now flip the cymbal over and this is where the flour comes in. Take a table spoon of your flour and drop it onto the crack, with your spoon work it into the crack with the base smoothing it around, use multiple spoons if necessary. then tilt the cymbal onto its side, and give it a few taps, then put it down as normal, and use a tissue to wipe off any flour.
Congrats you have now found the X Factor! The entire crack is then identifiable by the flour and you'll see areas of the crack you did not see before, Mark maybe 1mm after the crack to be sure, and then take it to a hardware store/tool shop and ask them if they can drill that spot. I would use a fairly large drill bit, nothing too major.
Congratulations! its pretty likely you have now eliminated the crack, You can now file down the actual crack to the drill point and smooth it down but thats completley optional. I will probably make a thread about this if my cymbal passes the test, and hope this helps.
Original Thread:
http://www.cymbalholic.com/forums/showthread.php?37585-Which-dremel-bit-for-removing-a-crack
EDIT:
Here's some pictures courtesy of Cymbalholic.
