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Kris

Brushing Vs. Spraying Clear Coat Effect Lure Action

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I thought I would put this out there for discussion. I was reading where it was stated that brushing on clear coat would cause you to loose and/or mess up the action of the lure. That it was better to spray on the clear coat.

I have always brushed my clear coat on and haven't seen any ill effects on the action of the lure.

Thoughts .....

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Several features are changed when you add an epoxy top coat:

Ballast - is increased by 1/6th of the weight of the epoxy applied. This is less than most people think, but still can be significant. If your lure weight increased by 2 grams by adding epoxy, then you have added 0.33 grams of ballast.

Volume - has increased by 5/6th of the weight of epoxy applied (using metric units, 1 gram of epoxy = 1/1.2 cm3) . This is hardly noticable, but does have a few knock-on effects. The volume increase means that the lure can carry more ballast. This is why the ballast increase is only 1/6th of the epoxy weight, the rest of the epoxy weight is carried by the increase in volume. You can test this out yourselves by trying the Archimedes dunk test, before epoxy and after epoxy.

Tow eye position - has effectively been moved forward or down, depending on the lure design. I don't think anyone has ever considered this particular effect before. But by increasing the volume, you have changed the balance between the area of the lip in front of the tow eye and the area of the body behind the tow eye. How significant this change is, I do not know, but I would imagine it is more critical for deep diving type designs, but I believe that this is the main reason why the lures action changes after epoxy is added.

Centre of gravity - is moved very slightly upwards and towards the centre of the body. This change is very small, but still worth mentioning. The effect on the lure is on its resting attitude, the nose down angle is reduced. But like I said, insignificant.

For all the above reasons, I always epoxy test lures. This avoids the disappointment of developing the swim that you want, only to have it vanish when you finish the lure. I always test swim with hooks too, for the same reason.

Adding epoxy to a lure need not be a hit and miss affair, it is easy to keep track of what you have added to your lure. You can weigh the lure before and after epoxy to find the amount added. The specific gravity of epoxy is 1.2 so you can easily calculate the volume and the ballast added. The Archimedes dunk test before and after epoxy will confirm these numbers. If you plan on building a suspending lure, you have two choices: Trial and error or get involved with the epoxy numbers.

Dave

Edited by Vodkaman

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Dave just covered epoxy top coat completely, and perfectly, as usual.

I used to allow 2 grams+- for epoxy when I used it on my wood swim baits.

If you are using a urethane, DN-type top coat, brushing will give you a slightly heavier coating, but the actual top coat weighs so little I don't think it matters, except with suspending lures. And water temps. affect suspenders so much, it's not possible to have a bait that suspends 100% of the time, so I would just err on the slightly lighter side. You can always add a little mor ballast with suspend dots.

I dip my plastic and PVC baits three times in urethane, and the effect on the buoyancy and action of the baits is negligible.

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we spray clears on smaller walleye sizeed lures. plastics can be cleared with thinner coats. automotive clears.

on larger wooden lures for pike and muskies we brush epoxy clears. on larger baits the weights from clears truly have no balance or floatation effects... i am sure on smaller bass lures weight balance has more effect then clearcoats.

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As far as how much topcoat gets on a lure, you can over-do it by spraying just as easily as by brushing. The only possibly valid point I can see is that brushing will tend to distribute a clearcoat differently than spraying it - leaving more clearcoat in the direction in which you brush it (usually toward the tail). But we're talking very very small differences in weight distribution here, so I think the effect is more theoretical than practical. It's true that ANYTHING and EVERYTHING you do to a lure, however minor, will have some effect on its performance. But we all have to put some kind of topcoat on a crankbait so that's a moot point. I usually work toward a final weight target when building lures, and figure the paint and topcoat at about .02 - .03 oz on an average size bass lure. Say we shift .005 oz toward the tail of the bait due to brushing the topcoat. Is that significant? It's not insignificant but saying that it will ruin the action of the bait is a gross exaggeration. It might even improve it!

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Several features are changed when you add an epoxy top coat:

Ballast - is increased by 1/6th of the weight of the epoxy applied. This is less than most people think, but still can be significant. If your lure weight increased by 2 grams by adding epoxy, then you have added 0.33 grams of ballast.

Volume - has increased by 5/6th of the weight of epoxy applied (using metric units, 1 gram of epoxy = 1/1.2 cm3) . This is hardly noticable, but does have a few knock-on effects. The volume increase means that the lure can carry more ballast. This is why the ballast increase is only 1/6th of the epoxy weight, the rest of the epoxy weight is carried by the increase in volume. You can test this out yourselves by trying the Archimedes dunk test, before epoxy and after epoxy.

Tow eye position - has effectively been moved forward or down, depending on the lure design. I don't think anyone has ever considered this particular effect before. But by increasing the volume, you have changed the balance between the area of the lip in front of the tow eye and the area of the body behind the tow eye. How significant this change is, I do not know, but I would imagine it is more critical for deep diving type designs, but I believe that this is the main reason why the lures action changes after epoxy is added.

Centre of gravity - is moved very slightly upwards and towards the centre of the body. This change is very small, but still worth mentioning. The effect on the lure is on its resting attitude, the nose down angle is reduced. But like I said, insignificant.

For all the above reasons, I always epoxy test lures. This avoids the disappointment of developing the swim that you want, only to have it vanish when you finish the lure. I always test swim with hooks too, for the same reason.

Adding epoxy to a lure need not be a hit and miss affair, it is easy to keep track of what you have added to your lure. You can weigh the lure before and after epoxy to find the amount added. The specific gravity of epoxy is 1.2 so you can easily calculate the volume and the ballast added. The Archimedes dunk test before and after epoxy will confirm these numbers. If you plan on building a suspending lure, you have two choices: Trial and error or get involved with the epoxy numbers.

Dave

Dave,

All I can say is you are the man! You sure can come up with some good stuff! I never have been that precise and just brush on ETex and let it cure up on my drying wheel overnight. It is usually evenly distributed and I really haven't noticed any difference in action. I mostly just make top water pencil poppers and haven't had to worry so much about diving lures.

Benji

Edited by benjiwhite

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As far as homemade wooden lures I don't think I have ever had one balanced to perfection to start with. Hence I've never thought this technical about my clears. I have been aware that different clears would change balance and action but to honest here I usually just brush it on and pray.

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BTW, I certainly didn't mean my comments to impugn what Dave said about epoxy topcoats! I always find his evaluation well thought out and interesting. I'm glad someone can do that, because it sure isn't me! But I assume we're not talking about epoxy in this instance because I don't know anyone who would try to spray it.

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BTW, I certainly didn't mean my comments to impugn what Dave said about epoxy topcoats! I always find his evaluation well thought out and interesting. I'm glad someone can do that, because it sure isn't me! But I assume we're not talking about epoxy in this instance because I don't know anyone who would try to spray it.

No problem BobP.

I wrote specifically about epoxy, because thick epoxies are the most likely culprit. If you are building lures with a wide tolerance, as mentioned by Mark, then the chances are that you would not notice any difference, even with an extra coat. If you are building close tolerance lures such as suspenders, slow sinkers or something close to the limits of performance, then choice of top coat will make a difference.

I build a lot of lures close to neutral buoyancy and also hunters which are close to the edge, so I have to control the top coat or I will lose the buoyancy and action. I can understand why a lot of members are writing that they see no problem. In fact good design is to build in enough tolerance that you can have a little lea way when top coating. I find that variations in wood density cause me more work than the epoxy top coat. Epoxy is constant, all you have to do is apply it exactly the same each time for consistency.

Dave

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A friend had a custom painted "Hell Hound" that had been dipped in epoxy and hung front up to dry. The epoxy ran to the tail and covered the two "planning projections" that come out each side of the tail. It just wouldn't glide correct. I repainted it and brushed on a thin coat of d2t and solved the problem. That is the only time I have seen a problem either way. Musky Glenn

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