Trondak U-40 Ls Supreme High Build Review- Part I

[Fishwhittler]

Trondak U-40 LS Supreme High Build review- Part I

Note: I bought the High Build version of U-40, not the regular. Whenever I say "U-40" in the following report, I'm referring to U-40 LS Supreme High Build. The same thing for Flex Coat: when I say Flex Coat I'm talking about Flex Coat Ultra V.

I read somewhere that a lot of the epoxies out there are the same thing, only in different packaging. This cannot be said of U-40. The resin component is much thicker than the resin in Ultra V, while the catalyst is slightly thinner. While mixing, I also noticed that U-40 has a stronger smell than Flex Coat.

Mixing: I did a little experimenting, and so far U-40 seems to mix best when I mix it the same way I mix Flex Coat. My technique is mix 1 minute, heat, and then keep mixing, heating at intervals of 45 seconds until you have mixed for a total of 4 minutes. Do not count the time heating as part of the four minutes. After mixing, heat the epoxy one final time and then cover it and let sit for ten minutes.

Viscosity: U-40 is considerably thicker than Flex Coat, and so you can probably use fewer coats. For example, if you use three coats of Flex Coat, you can probably use only two coats of U-40.

Bubbling: In my limited experience, U-40 appears to bubble more than Flex Coat. But on the package, it says to pour the mixed epoxy on a piece of foil, and I haven't been doing that. I will pour it out in the future to see if that fixes the bubbles.

Heating: U-40 doesn't react to heat the same way Flex Coat does. Heating Flex Coat while mixing will pop a lot of the bubbles, and at the end of the ten minutes most of the bubbles are gone. When I heated U-40 a lot of the bubbles would pop, but I still had quite a few bubbles in the mixed epoxy. More of the bubbles popped when I was brushing the epoxy on, but it for me it hasn't been as bubble-free as Flex Coat. Also, heating U-40 after it's on the lure doesn't do much to remove bubbles; it will pop some of them but it will also generate more.

Dry Time: U-40 sets up faster than Flex Coat, and is dry to touch in 4-6 hours. Flex Coat takes longer, usually 6-8 hours to dry. However, Flex Coat appears to cure faster than U-40, and after two days of cure time for each Flex Coat is a little harder than U-40 mixed on the same day. On the package it says that U-40 takes 5 days to fully cure, so I'll see how hard it is then.

Appearance: U-40 gives a beautiful, glossy finish very similar to Flex Coat.

Yellowing & Durability: I haven't had U-40 long enough to know how well it resists yellowing and teeth marks, but I'll try to post info in the next part of my review. That could take several weeks, so stay tuned.

[powerworm]

i personally do not make hard baits but i was reading your post and i got to thinking...i sure do wish the other forums would get back to posting reports like you did in an unbiased informative method!! my hats off to you nice article and very well written!!! jon/pw

[mark poulson]

Great report. Thanks for sharing.

I can't wait to get an update.

[Fishwhittler]

Here are parts II and III of my review of Trondak U-40 epoxy topcoat. Forgot to post part II the other day, so here it is along with part III.

U-40 review part II: Hardness

After more than 5 days of curing, U-40 is still not as hard as Flex Coat after the same period. In fact, Flex Coat is harder after eight to ten hours. I'm not sure whether this is good or bad, as the greater flexibility may be an advantage in resisting scratches. The difference in hardness is not much, but U-40 is slightly softer.

U-40 review part III: Fish Teeth Resistance

I took this bait fishing today to test the durability of the U-40. I caught four fish in one hour, plus two other strikes that I missed. The U-40 held up well to the fish teeth, and it still looks very good. Scratching was about the same as Flex Coat, so if there aren't any issues with yellowing I think I'll switch completely to U-40. Below are some pics of the bait after I fished it. There is one small tear in the topcoat where the hook point stuck in and then tore free, but this could happen to any topcoat and so is simply not part of the equation.

Scratch pics

Still to come: Yellowing

[mark poulson]

Nice looking lure!

What kind of fish did you catch?

[Fishwhittler]

Thanks!

I was catching bass. That's all there is where I fish except catfish, grass carp and bluegill, but those don't frequently bite crankbaits.

[mark poulson]

Thanks!

I was catching bass. That's all there is where I fish except catfish, grass carp and bluegill, but those don't frequently bite crankbaits.

I'm surprised their teeth could scratch the finish.

[Fishwhittler]

I'm surprised their teeth could scratch the finish.

Oh yeah, bass chew up finishes pretty good. This bait is no exception; if it was coated with Flex Coat it would look about the same after four fish. I've even received minor cuts from bass teeth.

[Jwags]

Fishwhittler,

You can eliminate bubbles in your epoxy by using an automatic mixer. Acidrod carries them. Also, be careful heating epoxy, you will rapidly decrease the cure time which will make it harder to get your bubbles out when you apply it to your lures.

I just switched to Diamond II from Bullard International and I love it. (I had been using Etex) It is also a guide wrap epoxy for rod building. It gets super hard, is very clear, and doesn't yellow as much or as quickly as the other epoxies. It is considered a medium build.

jeremy

[Fishwhittler]

Fishwhittler,

You can eliminate bubbles in your epoxy by using an automatic mixer. Acidrod carries them.

I may get one eventually, but for now I'm going to keep mixing by hand. At this point I don't mix epoxy enough to need one.

Also, be careful heating epoxy, you will rapidly decrease the cure time which will make it harder to get your bubbles out when you apply it to your lures.

I didn't have any problems with not having enough time to coat all my lures. However, U-40 does set up faster than Flex Coat, and after only an hour or two of dry time it was just about impossible to smooth out any imperfections. By contrast, Flex Coat can still be manipulated after a couple hours of drying.

On a related note, heating U-40 doesn't seem to do much to to pop bubbles. Heating will pop some, but after that it will only create more.

I just switched to Diamond II from Bullard International and I love it. (I had been using Etex) It is also a guide wrap epoxy for rod building. It gets super hard, is very clear, and doesn't yellow as much or as quickly as the other epoxies. It is considered a medium build.

jeremy

I might try Diamond II eventually, but at the current time I'm either going to switch to U-40, provided it performs adequately, or go back to Flex Coat Ultra V. Diamond II is more expensive than Ultra V, and I'm not sure there would be a large enough increase in durability to justify the extra cost (for me, at least).

Ben

Edited July 11, 2010 by Fishwhittler

[Fishwhittler]

Well, I've had U-40 for about a month now, and it hasn't yellowed yet.

I mixed some the other day, and then I decided to try something new: I'd use my finger to coat the lures. I saw the thread about using a finger to spread epoxy and I figured I'd give it a shot. Anyway, it worked great! I got fewer bubbles, and it was easier to completely cover each lure.

Also some more info about mixing: it mixes with fewer bubbles if you mix slowly. Flex Coat can be stirred hard and it will still lose a lot of bubbles when you let it sit, but U-40 needs to be mixed a lot slower.

[mark poulson]

Well, I've had U-40 for about a month now, and it hasn't yellowed yet.

I mixed some the other day, and then I decided to try something new: I'd use my finger to coat the lures. I saw the thread about using a finger to spread epoxy and I figured I'd give it a shot. Anyway, it worked great! I got fewer bubbles, and it was easier to completely cover each lure.

Also some more info about mixing: it mixes with fewer bubbles if you mix slowly. Flex Coat can be stirred hard and it will still lose a lot of bubbles when you let it sit, but U-40 needs to be mixed a lot slower.

If it doesn't yellow, it sounds like the perfect compromise between D2T and Etex, or Flexcoat.

[Fishwhittler]

If it doesn't yellow, it sounds like the perfect compromise between D2T and Etex, or Flexcoat.

It appears to be a pretty good topcoat so far. I like Flex Coat's ease of use and hardness better, but I'm not going to rule out either Flex Coat or U-40 until I've done more testing.

Edited July 30, 2010 by Fishwhittler