Try UV Knot Sense by Loon Outdoors [www.loonoutdoors.com]. For coating your fly line to leader connections, there’s nothing better, and it’s far superior for coating the heads on your flies. No mixing, no worrying about getting bubbles in the mix, no sloppy application tools [just squeeze it out of the tube]. The stuff runs very slowly so it can be worked into the shape you want. It doesn’t seem to yellow over time.
The catch? It hardens only under ultraviolet light. This means you can use it only on a sunny day when you can take your coated knot or fly out into the sun…or you can buy a UV light for use in the house. TIP: I bought a bulb through eBay for $6.00 that screws into a desk lamp. Newtown Bait & Tackle [www.newtownbaitandtackle.com/] carries UV Knot Sense and you can try a tube of it for $6.95 [plus tax].