Vodkaman

I'm just entertaining myself on my day off. I was assuming a two piece mould, so, as a one piece, the problem goes away. The venting on a two piece closed mould is to allow the air to escape, otherwise it would block the plastic and give you an incomplete pour.

Your method is as good as any that I have read. I particularly like the pre-assembly with dowel pins. What hinge method are you going to use.

I think the lure looks great, the loose gill idea is original at least as far as this site is concerned, I've never seen it before. It should snap into place just fine. Have you developed a venting strategy for the tail. If not it may save some heartache to get it sorted out before you make the mould.

I can't understand the necessity to permanently attach with braising and soldering. If you are careful making the joint, it should hold tight enough for this application. JM, I have never heard of that soldering technique before, nor any other for aluminium. The problem is the rapid oxidisation, but your technique solves it. Consider brass tube and sheet for the manufature, soldering with a light torch is simple.

Over the years, I have searched for the 'right' spring, but to no avail. My suggestion is use rubber. It doesn't get much cheaper, is available in diferent tensions, sizes and lengths. You can either buy rubber bands or buy it by the length from hobby shops. No, the will not out live the steel spring, but replacing the elastic once a year is not such a hardship. Well, it will do the job until you find your springs.

Surely the issue of water getting into the bait is not Jann's fault. We're the ones responsible for sealing.

This may be a problem caused by the swivel metal being too clean. The molten lead is adhering and flowing into the swivel. Untried suggestion, you could try lightly heating the swivel with a yellow flame to soot them up. Don't heat too much or you will spoil the mechanical properties of the metal.

You could reduce the stickiness of the tape by dabbing your tee shirt a couple of times to pick up some fluff. Has anyone tried masking with hot candle wax? Dissolve away in hot water when finished. Maybe too time consuming, just a thought.

Justifiable accolades Jim, you make reading the softbait articles interesting and informative.

The explanation for the ballast weight paradox mentioned in my reply above is fairly simple, but by the time I have finished explaining it may not seem so. It’s all about moments. I don’t mean those special moments in life, rather an engineering moment. A moment is a force times a distance. A simple example of moments is a lever. The force is your effort to lift the heavy weight with a lever, the distance is the length between the lever fulcrum and the force you apply. This is the clockwise moment. The anticlockwise moment is the weight to be lifted times the distance of the weight from the fulcrum. When the clockwise moments equals the anticlockwise moments, the lever is in equilibrium. One ounce of extra force and the weight lifts. Do not concern yourself with the actual forces or distances as we are not going to calculate anything. Consider the forces acting on the lure. Assume that the fulcrum is the eye position for now. Visualize the lure on the table in front of you, pointing to the left. The first moment is the lip. It is trying to rotate the lure anticlockwise. the force is the water acting on the lip, the distance is the centre of the lip to the eye. A second moment is the body behind the eye. This moment is trying to rotate the lure clockwise. The force is the water acting on the body, the distance is from the eye to the middle of the body surface. A third moment is the ballast. This is trying to rotate the lure clockwise. The force is the weight of the ballast acted on by gravity, the distance is from the centre of the ballast to the eye. You can continue this process to the n’th degree, depending on how accurate you want the results (if you were in a calculating mood). The buoyancy of the body material has an anticlockwise moment, each hook and eye has a clockwise moment, even the paint and finish has a clockwise moment. When all of these moments are calculated out, the lure finds a balance position or it reaches a state of equilibrium (in engineering speak). So the paradox stated that if the weight of the ballast is reduced then the lure dives deeper. When the weight of the ballast is reduced, its moment is reduced (force x distance). The ballast had a clockwise moment, so in the overall balance, the clockwise moment has been reduced, the result is the anticlockwise becomes stronger and the lure rotates nose down until the balance is restored. If the weight of the ballast was kept the same and the distance to the eye was shortened (weight moved forward), this would have the same effect. The moment of the ballast is reduced because the distance is reduced even though the weight is the same (moment = force x distance). In my original reply above, I stated that everything has an effect. The above is an explanation of that fact. Move the belly hook rearwards and its clockwise moment increases, resulting in an anticlockwise rotation of the lure (it now swims shallower). If a lure has death roll, the chances are that it is diving too steep, the clockwise moment needs to increase of the anticlockwise moments have to be reduced. To increase clockwise moment you can, a) increase the ballast, move the ballast to the rear (generally not a good idea), c) move the hooks rear and increase size, d) add a coat or two of epoxy. To decrease the anticlockwise moment you can, a) trim the lip length or width. Alternatively, the eye position can be moved forward to achieve the same. This is generally the preferred solution, but don’t discount the others, often the eye relocation is a destructive process if the eye is in the lip. To non-invasively establish the death roll problem, the moments of the lure can be adjusted by adding a little weight to the nose or to the rear hook. If one or other improves the situation then on the next build you can adjust the moments accordingly. I was right, it did get a bit complicated and I apologize for that. But it is worth reading it over a few times as understanding this engineering theory will make understanding the lure, its balance and problem solving so much easier.

Thanks Swede, I was looking a bit too deep there.

Here is an interesting paradox. A lure balanced and setup to dive at say 30 degrees. Reduce the ballast slightly and the dive angle will increase. Conversely, increase the ballast and the lure will swim shallower!

My guess is that the elastic flexes varying amounts during retrieval and this moves the effective eye position up and down accordingly, thus changing the action etc. Is this correct?

Thanks Tubinator, useful info. I guess the vacuum thing is fairly essential to avoid bubble flaws. How is everyone else dealing with the bubbles? This stuff is too expensive to waste 3 or 4 tries to get a good result.

Alman. On a lure, it is safe to say that everything has an effect, it is just a question of degree. The following is just my take on what is happening and because I am constantly changing my opinion on certain aspects of the lures mechanics, what I have to say cannot be counted on as the absolute truth. The main influence on how deep a lure will fish is mainly down to the position of the eye. As the water acts on the portion of the lure in front of the eye (mostly lip), the lure rotates nose down. As it does this, the body rear of the eye rotates up and into the flow of water. A point is reached when the forces in front and behind the eye are equal. This fixes the angle at which the lure swims. The lure then takes the path of least resistance, this means that, although the line is pulling the lure upwards at say an angle of 10 degrees, the lure could be swimming downwards at an angle of say 15 degrees. As the lip/body ratio increases, the dive angle increases. However, there is a limit. My current thinking is that once the lip swims perpendicular to the tow line and still has not found equilibrium or a balance with the body, then the lure will flip over or roll sideways in a ‘corkscrew’ fashion. This is what I understand to be death roll. The maximum diving capability of the lure is when the eye is positioned to balance with the lip close to perpendicular to the line. The position of the ballast weight relative to the tow line is quite critical also. When the lure is in its dive attitude, the ballast will raise above the tow line. There is a critical point, beyond which the ballast will cause death roll. Also, if the weight is in line with the tow line, the lure will become very reactive and can suffer death roll. In order to achieve the most action, it is necessary to flirt with these instabilities as it is the edge of stability that reveals the most action. This is the advantage that the hand made ‘lure-man’ has the edge over mass production. The hand made lure can be tuned for the best performance right up to the edge, production lures have to be manufactured within a window and this window cannot be allowed to stray too close to the edge. As for the weight of the ballasts effect on depth, I believe it has very little. Yes, tie a horse shoe to a three inch popper and it will scrape the bottom of the Mariana trench, but keeping the ballast to realistic values, the balance between the lip and body is far stronger than the ballast effect. So, most lures, even deep divers, are actually floaters. This allows the fisherman extra ammunition, in that when the lure stops moving forward, it rises. Try this simple experiment. Cast half an ounce of lead weight and reel it in as fast as possible, remembering the resistance feel. Repeat with a small lure of your choice. The resistance is many times greater. Another very important influence on depth is line. If the lure swims downwards at say 30 degrees to the line then the lure would reach a maximum depth during the retrieve when the line points down at 30 degrees to the waters surface. Unfortunately, the line exerts considerable resistance to the water and ‘bows’ in the water. The lure, swimming at 30 degrees to the line therefore reaches horizontal much sooner, never reaching its theoretical depth. The thicker the line the more water resistance, the less depth achieved. The most depth that people are reaching from normal cast and retrieve is 18 to 23 feet. As for the possibility to calculate the lure geometry, I love this question, because it was the first question that I asked. Unfortunately, the lipped lure utilizes vortex geometry for its action (did I hear a groan!), this is a very complex area of engineering involving frightening mathematics. I still believe that a simplified analogous calculation is possible, I searched for it and will again, but no progress so far. I recommend that you read up on ‘vortex shedding’ on the web, this will give you a good understanding of how the lipped lure moves and it is not complicated to understand. It pains me to say that experience cannot be beaten as far as lure design is concerned, but if you can understand the theory of what is happening then the experience learning curve is greatly reduced and can be counted in months rather than years. Best advice is to experiment and keep accurate measurements and records. Do not discard the failures as they are your best opportunity to learn. I suggest that you post the failures and we will all learn a bit more.

I think the vigorous mixing effort has created a cloud of microscopic air bubbles. It may take a few days for them to disperse, but when the plastic is heated for use, the problem should go away. Try heating a cup full to see what happens.

Alman, I cannot find any reference to a 'free sliding chain swivel'. Where did you read it? Can you post a link.

Welcome Manuel. It is good that you are searching and reading. Questions are good too, even if they have been asked before. Sometimes the old questions reveal new answers as the membership changes and grows.

If the patterns where placed in the bottom of the pour, the air would rise, away from the mould face.

NNNOOOOO, don't do it!!!!!

I like the use of the Spenser Wells artery forceps, a marvelous tool with many applications. Unfortunately, my supply has dried up since Mom retired.

I can't wait to see what you came up with. Thank's for the effort.

Thank's for clearing that one up for me.

That sounds like a good idea. If you have access to accurate scales, it could be worth doing a density test to see what it is that you have. http://www.csudh.edu/oliver/chemdata/woods.htm This link is the most comprehensive list of wood densities that I have found yet. Cut off a chunk of a shape that you can measure and work out the volume in centimetre cubes. Wieght the piece in grams. Divide the weight by the volume and compare the answer to the chart. This will give a rough guide, further web searches on the likely candidates should reveal colour and grain. The density value will also give a clue as to how much ballast you will be able to add and how much action you could expect.

What kind of rubber are you talking about? Most rubber discussed here at TU is RTV, room temperature vulcanised rubber. It is my understanding that vulcanised rubber does not melt. I am not an expert and have not used the stuff before, so I will be interested what others have to say on this subject. I did ask the question once before, could RTV be re-used, but I did not get an answer.