Most tip breaks are close to the tip top - usually an inch or two down from the top. If that's happened to your rod you can fix it & (overall) it shouldn't effect the action of the rod too much. Plus, this is a fix you can handle yourself pretty easily, with a little guidance. Here's how you do it:
1.) Prepare the rod for a new tip top where it broke off. If there are shards of material (graphite, fiberglass, bamboo) you'll have to carefully cut them off with a very sharp razor blade. You want a nice, even tip top - like it was when it was being built, only shorter now. After any shards have been dealt with, lightly sand the area where the new tip top will go with 1,000 grit sandpaper. Get the area nice, smooth, & clean.
2.) Find the size of top guide you'll need. There's a good chance that it will be a different size than the original, but even if it's the same size, now's a great time to put a new guide that's brand new on your rod. Tip tops, or top guides, are measured in 64ths of an inch. So, measure the diameter where your new tip top will go (best done with calipers, etc) & determine the size of top guide you'll need. There are many places to buy fly rod tip tops. HERE is my personal favorite.
3.) With the new tip top in hand & the rod ready, take a small needle file (or even a bent paper clip) & make sure there is no debris inside the new tip top. Once your sure it's clean inside, dry fit the tip top on the rod. It wouldn't be a bad idea here to put a small piece of masking tape below where the tip top will go. Mark a line on the tape that will help you line up the new tip top with the other line guides. This will make it easier when positioning the new tip top on the rod.
4.) Mix up a small portion of two part epoxy. It's better if you use an epoxy with a slow set-up time & a high bond strength. With a small round toothpick, put some of the epoxy into the tip top's tube. Next put a little on the end of the rod. Now gently slide the new tip top onto the rod. You might hear small "popping" sounds - that's okay because that's the air escaping from around the glue. Don't use too much pressure - the rod should never bend while you're doing this. Make sure you have the tip top lined up with the other line guides - sight down the rod section to make sure - & then clean up any excess glue with rubbing alcohol (or whatever the epoxy manufacturer recommends. Now set the rod aside, allowing the glue to set up completely.
That's it!!! It's really not that hard & I think just about anybody can handle this job. With a little time & patience, your fly rod will be back on the stream landing fish in no time.
As always with rod repairs, if you run into problems or have questions before you start, contact a competent rod maker. Of course I'm always willing to help you out, & you should feel free to email me anytime. I hope this little tutorial has helped at least a few heartbroken anglers.