If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Archimedes
The floating materials thread has me thinking, indeed I woke up at 4 AM
trying to get some ideas straight in my sleepy head. Seems to me that flies float from a combination of factors. 1) true "lighter than water" materials ... these displace more weight of water than they weigh . One interesting thing the fly designer should note is that such materials ABOVE the water do not help float the fly, any more than the part of a ship above the water displaces water and adds buoyancy. I suggested dense foam in the other thread not because it is lighter, rather because it can be shaped better, trimmed from fat to thin quickly to go from tie in point to "displacement" size in a very short distance for small ties 2) surface tension ... something I don't "really" understand ... but we all know that slightly heavier than water items can be made to float by placing them gently on the film. My observations of the bugs indicates that they rely heavily on the film for support, after surface emergence is well under way, and as adults ... I'm betting our flies should, too, to look most real, at least at times. 3) trapped air .... probably the reason most commonly used materials in #1 are lighter than water, but some tying styles use the idea too, such as a loosely tied folded emerger wing. The bugs use this too, we're told. ( I've spent hours trying to actually "see" a caddis emerge, without success, but I've closely watched many mayflies and midges ... the 'bubbles" are there but far less obvious than all the glitter in many patterns .... indeed I'm inclined to belief that most caddis emerger patterns function as attractors from the overuse of antron and z-lon, since I've never been able to see anything nearly as bright in hours of trying ... ah, not that there is anything wrong with attractors, they work, .... and some of my best friends fish attractors, ... I even had a roommate that fished attractors ... I wouldn't want my son to fish them, of course :-) 4) chemical help .... again, something I don't really understand .... but I think most of the times this simply keeps materials from absorbing water, gaining weight, and changing from type #1 to non-type #1 materials. But, I think there are other factors, in the best chemicals ... a water repellency that increases local surface tension, or something ... as I've seen emergers with closed cell foam wings float better when JUST that foam was treated ... hard to believe that is the result of stopping water uptake 5) Other factors ??? ............................................. Anyway, I think "float" is the most important part of fly design, and not just "dry fly" ... a wet that won't sink isn't a good fly, either. By, "float" I mean the "presentation" aspects of the design ... if it's supposed to be "half in, half out" it needs to float that way every time, and gain that float quickly after touch down ... if it's supposed to represent an adult midge standing on the film on extra long legs, it has to stand on the film, body raised, .... wets need to sink to the right depth, etc. etc. Second place on my list of design criteria would be the practical considerations ...durability and castability ( there is no such thing as a "good fly" that uses stiff winging and twists my leader, for instance ) Once those two things are handled, then the more commonly discussed traits of size, shape, outline, color cab v\be addressed .................................................. ....... Anyone that really understands surface tension, and how the fly tier can use it or the chemical and why the best work better .... please post the knowledge ..... I think most of us would benefit, as we design our patterns and fish them |
#2
|
|||
|
|||
Archimedes
"Larry L" schrieb im Newsbeitrag ... Well, most chemical "floatants" are not floatants at all but waterproofing agents. All dry material like feather, fur etc, floats when it is dry. It is keeping it dry which is the problem. There are no chemical treatments which will give a fly positive buoyancy. Some of the newer chemicals are hydrophobic. Material treated with them actually stays dry, and therefore floats. Some "floatants", rely on the material being soaked with a hydrophobic material, or at least a material which is immiscible with water. ( Gink, Paraffin, silicone grease, wax dissolved in various solvents). Others are hydrophobic in their dry state, ( Watershed etc). The material thus does not soak up water. The principle is the same, but the dry materilas donīt wash of as easily as the liquid ones. Cohesive forces between liquid molecules are what cause the phenomenon known as surface tension. Surface molecules do not have other molecules on all sides of them, and consequently they cohere ( cohesion = "stciking together"), more strongly to those with direct contact to them on the surface. This effect forms a surface "film" which makes it more difficult to move an object through the surface than to move it when it is completely submerged. Surface tension is typically measured in dynes/cm, the force in dynes required to break a film of length 1 cm. Equivalently, it can be stated as surface energy in ergs per square centimeter. Water at 20°C has a surface tension of 72.8 dynes/cm compared to 22.3 for ethyl alcohol and 465 for mercury. If you wish to hold a fly ( or anything else) "in" , ( as opposed to "on") the film, then it must have at two entirely separate properties. It requires positive buoyancy to keep one end floating, and it must also sink at the other end. This is further complicated by surface tension. Surface tension in water is caused as a result of hydrogen bonding. As stated above, water molecules at the surface of water are surrounded partially by air and partially by water. These surface molecules are more stable when they are completely surrounded by liquid, as all their hydrogen bonds are then fullfilled (cohesion). This is why water tends to have the smallest surface possible, i.e. it has a high surface tension, in order to maintain the lowest energetic state. If a solid material, more dense than water is placed on the surface of water, then what happens, depends on the nature of that material. If the material is hydrophilic ("water loving") water is attracted to its surface. This adhesion of water, to the materialīs surface, reduces the surface tension, and causes the object to sink. If the solid object is hydrophobic ("water fearing"), then water is unable to coat the surface. Two distinct forces now come into play -- the energy required to overcome this repulsion, and gravity. If the force of gravity is strong enough, it will prevail and the object will sink (assuming that the object has a density greater than water). If gravitational force is less than the surface tension. then the object will float on the surface of the water. Surface tension is what allows insects to walk across the surface, and enables a needle to float. The critical feature, is is the amount of force per unit area. If you put a needle into water end-on , instead of sideways, then the needle will immediately sink Adding detergents and other things to water changes these properties radically. One hundred years ago, it was much easier to float a fly, as there were many streams which contained no detergents, road run-off., etc etc. Displacement is another problem. A material which is less dense than water ( Cork, wood etc etc) displaces itīs weight in water, but continues to float. A material which is denser than water, once it has penetrated the film, displaces its volume! in water, not its weight! For instance, say you have a concrete bucket anchor in your boat. You throw the anchor over the side, what happens? The boat rises in the water, as it is now carrying less weight. The water in the lake ( although of course you wont notice this ) actually goes down, because the concrete is more dense than water, and is now displacing its volume, and not its weight. Hope this helps! TL MC |
#3
|
|||
|
|||
Archimedes
Larry L wrote: 2) surface tension ... something I don't "really" understand ... but we all know that slightly heavier than water items can be made to float by placing them gently on the film. My observations of the bugs indicates that they rely heavily on the film for support, after surface emergence is well under way, and as adults ... I'm betting our flies should, too, to look most real, at least at times. I think that's why it is often difficult to take fish when they are feeding on small insects. Their orientation in/on the film are hard to consistently reproduce with an artificial fly. 3) trapped air .... probably the reason most commonly used materials in #1 are lighter than water, but some tying styles use the idea too, such as a loosely tied folded emerger wing. The bugs use this too, we're told. ( I've spent hours trying to actually "see" a caddis emerge, without success, but I've closely watched many mayflies and midges ... the 'bubbles" are there but far less obvious than all the glitter in many patterns .... indeed I'm inclined to belief that most caddis emerger patterns function as attractors from the overuse of antron and z-lon, since I've never been able to see anything nearly as bright in hours of trying ... ah, not that there is anything wrong with attractors, they work, .... and some of my best friends fish attractors, ... I even had a roommate that fished attractors ... I wouldn't want my son to fish them, of course :-) Below is a link to a MPG of an emerging Mayfly. The film was taken by a guy that was raising nymphs in an aquarium. Fast and silvery. http://www.njflyfishing.com/vbportal...09/1Fuscom.mpg 5) Other factors ??? ............................................ Anyway, I think "float" is the most important part of fly design, and not just "dry fly" ... a wet that won't sink isn't a good fly, either. By, "float" I mean the "presentation" aspects of the design ... if it's supposed to be "half in, half out" it needs to float that way every time, and gain that float quickly after touch down ... if it's supposed to represent an adult midge standing on the film on extra long legs, it has to stand on the film, body raised, .... wets need to sink to the right depth, etc. etc. I'm a "presentation" man too. Second place on my list of design criteria would be the practical considerations ...durability and castability ( there is no such thing as a "good fly" that uses stiff winging and twists my leader, for instance ) Once those two things are handled, then the more commonly discussed traits of size, shape, outline, color cab v\be addressed Although I agree that the "how" is most important, size is also often critical. The rest, far less important. Willi |
#4
|
|||
|
|||
Archimedes
"Willi" wrote in message http://www.njflyfishing.com/vbportal...09/1Fuscom.mpg WAY cool, thanks Willi. I love things like that, and it can be so much harder to see, on the stream, than one would think. I've watched many mayflies free themselves from the shuck and more than a few nymphs swim/ float the last inch or two to the surface to do so, but I've never had that much of a "silvery" impression from ABOVE ... the only view I've had Where did I put my Antron ??? G |
#5
|
|||
|
|||
Archimedes
"Mike Connor" wrote in Hope this helps! You might consider hiring yourself out as an encyclopedia, Mike g Thanks buddy |
#6
|
|||
|
|||
Archimedes
Great post Larry! It's posts like these that make reading through all the
off topic BS worthwhile. May I add two categories? 5) Lighter than Air. In order to offset hook and overall bug weight, I've often thought of reducing bug weight by substituting trapped hydrogen, helium, methane and/or other gasses in lieu of trapped air to make bugs float higher. I've experimented with using these gasses in foam for bugs but found it difficult to work with. Guess I need to find a plastics injection engineer who fly fishes - LOL! Foam problems include: Too hard, too soft, hard to color, hard to drill, hard to glue, hard to shape, hard to remove from molds, etc. Also I frequently embed plastic or glass rattles in my cork popping bugs. I've injected helium in plastic straws with BBs to offset weight but found them hard to work with. With all the bass tournament boys experimenting with various materials making worms, grubs, minnows, crawfish, etc., in the future expect to see lighter than air injections in their innovations. I expect to see frogs and snakes included in this technology in the future. 6) Mechanical devices. Floating lures can be made to dive when retrieving by using a scoop on the front. The reverse can also be used to keep them on the surface. I scoop a 15 degree (top to bottom) slope on my Chug Bug popping bugs to provide motion during retrieval but it also helps keep them on the surface. This approach presents many difficulties when working with unruly materials. My pathetic attempts to trim hair into a reverse slope come to mind . g A major limitation of this approach is that it only works while the bug is being retrieved. When not being retrieved, it provides no flotation capability. Anyone having any thoughts on how to make any of the 6 categories "work" better will surely be appreciated. Thanks again Larry. Good luck. John "Larry L" wrote in message ... The floating materials thread has me thinking, indeed I woke up at 4 AM trying to get some ideas straight in my sleepy head. Seems to me that flies float from a combination of factors. 1) true "lighter than water" materials ... these displace more weight of water than they weigh . One interesting thing the fly designer should note is that such materials ABOVE the water do not help float the fly, any more than the part of a ship above the water displaces water and adds buoyancy. I suggested dense foam in the other thread not because it is lighter, rather because it can be shaped better, trimmed from fat to thin quickly to go from tie in point to "displacement" size in a very short distance for small ties 2) surface tension ... something I don't "really" understand ... but we all know that slightly heavier than water items can be made to float by placing them gently on the film. My observations of the bugs indicates that they rely heavily on the film for support, after surface emergence is well under way, and as adults ... I'm betting our flies should, too, to look most real, at least at times. 3) trapped air .... probably the reason most commonly used materials in #1 are lighter than water, but some tying styles use the idea too, such as a loosely tied folded emerger wing. The bugs use this too, we're told. ( I've spent hours trying to actually "see" a caddis emerge, without success, but I've closely watched many mayflies and midges ... the 'bubbles" are there but far less obvious than all the glitter in many patterns .... indeed I'm inclined to belief that most caddis emerger patterns function as attractors from the overuse of antron and z-lon, since I've never been able to see anything nearly as bright in hours of trying ... ah, not that there is anything wrong with attractors, they work, .... and some of my best friends fish attractors, ... I even had a roommate that fished attractors ... I wouldn't want my son to fish them, of course :-) 4) chemical help .... again, something I don't really understand .... but I think most of the times this simply keeps materials from absorbing water, gaining weight, and changing from type #1 to non-type #1 materials. But, I think there are other factors, in the best chemicals ... a water repellency that increases local surface tension, or something ... as I've seen emergers with closed cell foam wings float better when JUST that foam was treated .... hard to believe that is the result of stopping water uptake 5) Other factors ??? ............................................ Anyway, I think "float" is the most important part of fly design, and not just "dry fly" ... a wet that won't sink isn't a good fly, either. By, "float" I mean the "presentation" aspects of the design ... if it's supposed to be "half in, half out" it needs to float that way every time, and gain that float quickly after touch down ... if it's supposed to represent an adult midge standing on the film on extra long legs, it has to stand on the film, body raised, .... wets need to sink to the right depth, etc. etc. Second place on my list of design criteria would be the practical considerations ...durability and castability ( there is no such thing as a "good fly" that uses stiff winging and twists my leader, for instance ) Once those two things are handled, then the more commonly discussed traits of size, shape, outline, color cab v\be addressed .................................................. ...... Anyone that really understands surface tension, and how the fly tier can use it or the chemical and why the best work better .... please post the knowledge ..... I think most of us would benefit, as we design our patterns and fish them |
Thread Tools | |
Display Modes | |
|
|