First, if the bare threads are coming loose or fraying, they’ve been exposed to the elements under fishing conditions and the wraps are compromised; merely coating these wraps with new finish will result in a substandard job from an aesthetic point.

If you want a professional job and wouldn’t describe yourself as an experienced rod builder, I’d really suggest scouting for the right person to completely redo all the rod wraps with new thread and new finish. It won’t take an experienced person long to restore the rod to its original condition, so the fee should be quite reasonable (unless you want the guides replaced at the same time). If you don’t know where to find such a person locally, check out the fishing forums or, preferably, locate someone through one of the rod building forums. Many of the casual, amateur, yet experienced, builders that post there do work at a quality level that you won’t see in any production rod today.

If getting a professional result isn’t critical to you or if finances are limited, you can rewrap the guides in question and refinish with your choice of available rod finishes. I’d recommend going with a 1-part finish as opposed to the two-part "epoxy" finishes on the market. The 2-part finishes require experience to get right; they’re finicky about getting the mix ratio EXACT and best results are obtained with adding small amounts of acetone to the mix. Failure to get it right results in a finish that stays sticky, never seems to harden, or gets cloudy. In the 25+ yrs I’ve built rods, products have improved, but it’s still easy to screw up if you don’t know what you’re doing. And if you don’t get the finish mixed or applied correctly and wish to remove and redo it, it’s not much fun.
References :

While there are several special coatings made for rod wraps, they’re not absolutely required. Instead you have two readily-available alternatives:

1. Clear nail polish. Keep in mind this is a lacquer, and it’s possible to chip and craze it. So use several layers. Apply one thin one. Let it dry, and apply another.

2. Two-part epoxy. Just make sure you have equal parts of the adhesive and hardener. Mix them well together (they’ll initially look cloudy, but ignore that). Apply to the thread wraps. If you feel it necessary, a second coat can be applied. But you don’t need more than that.

No matter what adhesive you choose, it is crucial that you slowly rotate the rod until the coating sets. Otherwise it is likely to slump in the direction of the ground. To assure the best results, do one guide at a time, rotate the rod until it sets, then let it sit overnight to fully harden. Then do the next one.
References :

Dont forget youre glue is only as good as youre whippings, if you have any doubt about a whipping do it again as no matter what epoxy you use they will come loose if not correctly whipped.
References :

1) U-40 Permagloss (my personal choice)
2) Gudebrod 1 part regular build rod finish

The U-40 is about $2 more for a small bottle and
and takes longer to dry, but the finish will outlast the rod itself. Brush on a thin coat, and if you don’t have a rod wrapper, turn by hand for about 20 minutes
Remember -THIN is the key. You’ll need about 3 coats
to due the repair properly – Do not attempt to due this in one day, it takes abour 24 hours to cure. Coat, rotate, dry, repeat the next day. Use a small hobby brush to apply the finish, then throw the brush away.

Gudebrod – Pros: water clean up, dries completely in about an hour. Cheaper also. You can do the repair in a day – Coat, rotate, dry, repeat. You put it on with a small hobby brush, which you can then cleanse with water.
Cons: not as durable as U-40

Both products are available at either Cabelas.com
or JStockardflyfishing.com

References :
Rod builder for many years