Leveling out is one of the characteristic strengths of epoxy. If you want a resin which
doesn't spread out, the UV as suggested by Pat Lat is probably a better choice for your
use here. It will tend to stay put once you hit it with the UV light.
Also five minute epoxy yellows and cracks quicker than the longer cure varieties. But that
is only a problem if the fly is kept unused for an extended period.
According to my older brother who owns a hobby shop, the five minute epoxy uses a water base -- that's why it dries so fast.
So, it isn't the greatest to use in or around water. A friend built a rod for me and used the fast drying epoxy to attach the butt cap. After a year or two of exposure to water (sometimes the rod and reel seat do get wet) the butt cap fell off. I almost lost my reel.
He no longer uses the fast drying epoxy.
For use with a fly pattern, I go with the new products on the market dedicated to fly tying... as the UV coating mentioned above.
After using UV cure I can't see myself going back to epoxy ever again. It is so quick and easy now that someone actually makes a tack free UV cure.
My turning wheel gets very little use now.
When I used epoxy, I always used the 30 minute. Less yellowing and I could do a ton of flies without it setting up to quickly on me.
I don't think any epoxy uses a water base. Epoxies harden chemically when hardener is mixed with resin. Water isn't involved. As Ron pointed out the longer the cure the stronger the resin. 5 minute stuff is brittle and not terribly strong. 20 minute stuff is as strong as glue gets. Or near it anyway. 6 hour boat building epoxy is better yet.
UV cured resins are extremely handy. But none I've seen are near as strong (bonding wise) as a good epoxy.
In regards to the fast drying epoxy, I stand corrected. I contacted my brother and he indicated that the first fast drying epoxy did not do all that great when exposed to water.
The newer products are much better. However, it depends on which quick drying epoxy you buy as to how well it works in water. Some indicate they are water resistant not water proof. Some manufacturers do offer quick drying epoxy that is indeed listed as water proof. So, when it comes to the fast drying stuff for use with fly patterns, it depends on which brand you buy as to how well it will hold up in water.
Chances are, you'll lose the pattern or some other part of the pattern will go gunny bag before the epoxy gives up the ghost so at this point, I guess it doesn't matter if you use the fast drying product or not.
Personally, I go with the new waterproof coatings that dry clear so I don't mess around with any epoxy.
I can't speak for the bonding strength of epoxy as I generally use super glues etc if I want to bond something together like eyeballs to a hook.
As far as the durability, I've been pleasantly surprised by the UV resins I've used. I spent a good many years beating up Puget Sound beaches with flies and I really haven't noticed the UV cures to be any less durable then epoxy.
You know how you fix those epoxy problems? Use a UV epoxy. It takes 7-10 seconds to cure, comes in a variety of thickness', doesn't have a limited working time, doesn't yellow. Its not the 90's anymore, you don't have to use epoxy.
There are NO UV cured epoxy fly tying resins. They are all UV Acrylic resins so the term UV cured epoxy should not be used to described the fly tying UV resins.
There are two types of UV cured resins. The first type are acrylics that cure by free radical polymerization and epoxies that cure by cationic polymerization. ALL UV fly tying resins are acrylics and NOT epoxies.
There are three major differences between UV Acrylics and UV epoxies.
The key reason UV epoxies are not used in fly tying is that once the proper UV light activates polymerization in UV epoxies, it continues and CANNOT be stopped. UV acrylic polymers require UV light to complete polymerization so you can control polymerization of UV acrylics but not UV epoxies. So there is a marked limited working time with UV epoxies. Also if you accidentally hit UV epoxy in the bottle or syringe opening with UV light polymerization will initiate and the entire supply of epoxy will solidify.
Both UV cured acrylic and UV epoxies shrink as they cure. However, the UV epoxies have minimal shrinkage. So they are used in critical applications where the manufacturing process cannot accommodate the volume loss of UV acrylic polymers.
The third difference between the two resins is that oxygen inhibits polymerization of UV activated polymers. Since UV epoxies cure by a different method, the cure cannot be stopped by competing Peroxy free radicals.
The curing time of the various UV fly tying resins depends on how thick you apply the resin. The curing process is also exothermic which means heat is produced as the resin is cured. So if you have a fast curing resin and you put on a thick coat, the heat cannot escape and the resin will "cook" and discolor.
Some fly tying resins never cure completely with the UV flashlights that are sold. The ones I have tested will not even cure with my UV laser. They have a sticky surface due to the oxygen free radicals that stop the cure. That why the surface which is in contact with the air fails to cure and remains sticky.
There is a fine balance then how fast a resin actually cures and it's resistance to oxygen inhibition. Too fast a cure and the resin cooks and too slow a time and it may never cure.
Before you spend money on a UV cured fly tying resin, ask if it cures absolutely tack free and how fast it cures. If possible ask to test a sample in the fly shop. It will prevent having to coat the resin with Sally Hansen's to get a tack free surface
I have purchased resin and UV light, including the UV laser cool from member Silvercreek. I'm very happy with the purchase transaction, price, and products. Perhaps he is still selling. You can purchase UV resin in large quantities online (chemical supply, dental supply, etc...) at not very exorbitant prices but an ounce or two will go a long way.
Silvercreek speaks the truth. I was extremely disappointed with the varies UV cures I had tried. All claimed to be tack free, but were not.
Silvercreek's UV cure are tack free. I highly recommend his light as well. Well worth the money in my opinion if you want to get into using UV cures.