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With small lures, members discovered that very thin fiber/circuit board lips were more effective than thicker Lexan lips in creating waggle action. The thinner the lip, the better the action. The reason for this has not been discussed much, if at all. It is all about the sharp edge. Water can flow around a round object with minimum 'peeling off' of the flow, thus minimum disturbance of the water. Conversely, flow cannot negotiate a sharp corner; it cannot change direction that quickly. This causes a low pressure area behind the edge of the lip. Water gets sucked back into this low pressure area and thus the vortex is born. At very slow speeds, the shape of the water flow is symmetrical, the same both sides of the lure. But, as the lure speed increases, a certain speed is reached were the vortices start to interact. There is not enough room for the vortices to exist independently so they take turns. The vortices start to alternate, forming one side then the other. This effect is called ‘vortex shedding’, a ‘vortex street’ or ‘Kármán vortex street’. This alternating vortex is the engine that drives the lure, causing the desirable ‘waggle’ or action of the lure. This also explains why a lure has a minimum speed before the action starts. The sharper the edge is, the stronger the low pressure area, the stronger the vortex and therefore the stronger the action. Larger lures in the range of 8” and larger will require a thicker lip in order to survive bouncing off rocks with all that body weight behind. But the thicker lip is not going to produce as much action as the knife edge lip of the 3” lure. The solution is to cut a chamfer behind the lip face. This reintroduces the knife edge and improves the vortex strength and thus the action. Another way to improve action is to make the face of the lip concave. This causes pressure to build up in front of the lip which further increases the strength of the vortex. Here is a video that shows vortex shedding, and the start transition explaining the minimum speed. Dave

Just remember that dust is explosive, and water-based paints create dust when they dry. So buying more expensive filters might actually work against you, because you'll be more hesitant to change them as often as you should.

The things we do in search of a fish.

Hi Marc- You would think it would,,, as its that collapsible AC ducting 4". As with PVC tube, some say yes, others say it's all B/S- I suppose to be on the safe side it wouldn't take much to do, never been zapped yet, but if it exploded it would be a drama. You probably remember I built this one years back and have added 2 more tubes since, which works much better-- Its a "downdraught" set up, air is drawn down then up through the 4 tubes to the "Fan Box" and then expelled outside, through the shed wall.

Hi Dan Not sure if paper filters would be the best option for paint. I know there are a lot of people using them but as you say the motor H.P requirements need to be big . The problem with paper /fiber glass is paint tends to dry/ or "set" very quickly when blasted with air (especially thinners based paints), so it will quickly start blocking the filter which restricts the air flow which allows more paint to set in the filter, so around and around it goes and probably starts drawing air around the filter or from the back. Lots of guys use "flash proof" Gas Heater fans from old home gas heaters. The overspray is transferred (suction) via a spray booth (box) into corrugated plastic or Al (heater ducting) ducting along which it travels through the fan (squirrel cage heater fan) and out to the atmosphere. If you use enough flexible ducting (4" or Bigger) the paint solids tend to set in the ducting, not the fan blades, the solvents or water will be expelled through the fan- which MUST BE FLASHPROOF. Connect the ducting via PVC pipe fittings. Bash the ducting occasionally and the paint solids will fall off as paint dust. Had one for years and still works as new, still passes the required air volume tests too. Pete

Building your prototype out of waterproof material like PVC decking speeds up the testing process, because you don't have to worry about water intrusion every time you make a change. Once you have a lure that works, you can duplicate it in whatever building material you like, so only have to fine tune it before you paint and finish it.

Being it’s the holiday season, I thought in the spirit of giving, we all could share our knowledge with one important piece of advice or something you would have told your younger self that would have saved you a lot of time and trouble. For me, I would have told myself to focus on function, not form, looks and being anatomically correct doesn’t matter, just get it to work. Merry Christmas to everyone and thank you for all of your help this year, it’s been invaluable.

1) Don't be afraid to try new things. 2) Slow down and work on a quality finish. 3) Don't be in a hurry to sell, build and improve quality first! 4) Test lures before painting them. Merry Christmas and thanks to everyone for all the insight you have shared!!!!!

This is a great explanation!!! get off your A$$ and do it in real life, just don't sit read and watch videos.

A mistake that I made in the early days of lure building, was testing without hooks fitted. The addition of hooks in weight and fluid effects changes the action of the lure, sometimes sending the lure outside the design idea, or at least disappointing after the initial hookless trials. So my contribution is; Always fit the hooks for testing. Dave

45mm is pretty small. I'd get a small rapala the same size and compare, to see if it's a user function or if its bait function. If the Rapala and your lure both dont do what you want then you'll have to work more on design. I'd think at that size you could make big changes with suspend dots made by storm. when you over power a lure they will blow out.

https://www.wlure.com/pages/search-results-page?q=treble accessories

If you want a stable cranking action, just put the weight at the lowest part on the belly or wherever the pivot point is and throw a classic square lip or round on it. But, experience is a big part on this one like Hillbilly Voodoo said.

Yes, the human brain is a wonderful thing. If you do the experimental work and build enough lures, the brain develops 'a feel' for what is correct, without you ever really knowing why! Dave

If I had to rely on math to build lures I probably would have got bored and gave up Luckily I am really good at being stubborn and the good old trail and error method works if you keep at it To this day I make at the min a reject lure a week messing around

I spent a lot of time trying to math my way out of trial and error, some of it very good, some not so good. When it comes down to really understanding something, trial and error is most powerful. Dave

Thanks I had no one to teach me and went through a lot of frustration being clueless. After lots of failures this was my way of figuring out what I was doing wrong and then used it to experiment Wish I had TU back then but I would say I probably figured out things by trying stuff I would have never learned if someone told me how to build lures

There is a ton of knowledge on this forum that can make your learning process easier but going out and trying things is always good Going out and trying different things is how you stumble on something amazing. Doing everything the same way as everyone else will limit you to everything that has already been done before

Thanks for the response. Makes sense (or at least as much as my very limited knowledge of hydrodynamics will allow). I think it's going to just come down to trial and error, which can in itself be fun.

Ok you can do lots of different things messing around with weight placement so your question could really go into an essay. Most common reason for weight placement is leveling the bait so the water catches the lip on the correct angle. Most common is weight place near the front hook to achieve the slight nose down most go for with crankbaits Now you can also impact action by causing the bait to be unstable. Think of the classic belly weighting as creating a keel to stabilize the bait. Move that keel closer to center (top/bottom)it changes the pivot point in the action. Now where you position it from front to back plays a roll as well. Closer to the front has less impact on the action but weight towards the tail tightens things up or robs action Hope at least part of that makes sense I recommend doing what I did years ago it will teach you a lot about impact of weight and placement on action. Make some blanks, drill holes in different locations so you can put weight in different spots and pull it back out. Seal the blanks give them lips( if you want just pressure fit lips so you can try different ones) and go play in the water You will learn a lot about weighting and action by going out and playing around with different placement. It will probably put you way farther a long in knowledge then listen to this redneck ramble lol I learned a ton about action from trying things and some I have a hard to explain. It you think in pivot points, catching water pressure, cutting through the water, and adding/robbing power with weight or poor/good hydrodynamics these are big factors

OK, I dug up some old and a few new attempts with convex and concave lips. As we know there can be a lot of variables in action and depth with just one lip shape- I wonder why it's not used a lot more ''Text'' is on each photo, just in case I can't post this many pictures here -----hope this is legal, otherwise I will post them in my attachments, or somewhere?? Pete **** SORRY, pic's 4 and 5 should read ''Concave Lip"

I saw a bait in the competition baits; with a similar cut but under the chin. I was very impressed, and if I had a workshop, I would be out there now, carving away a test piece. Dave

Back when I was playing around with moving ballast I made three "identical" crankbaits, using an already successful design. All of those had a concave forehead, leading to the back (I misspoke when I said concave back) . They had a tight Xing (wiggle) and ran down to 6'+-. Without the concave the same bait would only run down 4'+-. The moveable ballast was at the kill spot. The higher the ballast, the more erratic the bait would act on the retrieve (hunting).

Very interesting read! I missed when this was originally posted. I have a large musky crankbait that I designed for shallow use but when I tried it out, the action was minimal. Note to self, when prototyping a lure, make the lip oversize so it can be paired down to optimal size. The lip was too small in my case (and thick) to produce the action I was hoping. But after reading this I think I can cut a chamfer in the backside of the lip to see if this will increase the action. And if that is not enough, I could even sand away the face of the lip producing a concave shape. I will experiment with it and see if I can get it useable! As always Dave, excellent research and information on a very complex topic.

Mark - a concave face, which is what you are talking about, is going to increase the vortex strength, a convex will reduce the action. As for '.....to the back', I am not sure what a concave cut into the back of the lure would have. I think it may have an effect on roll. I have just checked a few of my under water videos, and I think that a hollow feature down the back might reduce roll. I am thinking that it would have a similar but lesser effect of having a dorsal fin down the center of the lure. To kill the roll would only require a short dorsal fin, say 5mm (3/16"). But again, as with all my stuff, this is theoretical, but it does fit. Often it is difficult to see what effect, if any, such features have. I am thinking back to my 'various lips' video, were I compared round, square, coffin and shaped lips. It was very difficult to see any difference between round and square, also coffin and shaped. Likewise, your concave back will be a subtle effect. In order to confirm an effect, you have to exaggerate the feature; a wide shaped body with an exaggerated concave back, directly comparing with the exact shaped body with a rounded back. And then, you may need close video, preferably submerged, head on, to observe the difference if it is too subtle, but if the effect is too subtle when exaggerated then then there is hardly any point in taking it further. Who knows, there may be another new idea waiting to be discovered. Whether roll is a good or a bad thing, I do not know. What I do know; is that fish do not roll when they swim. Personally; I do not like roll, but I know other very experienced builders do. So, after pouring my thoughts out, getting back to your point; I think more action due to the concave front end, and a more stable swim (less roll) due to the concave back. Boy I wish I had my workshop and a test tank, I would be out there right now. carving up a bunch of test lures, to test this idea and the lip/body funnel effect. I hope someone takes on these ideas and comes back with a report. BUT, they re only ideas, they not pan out. Of course, rattle traps swim back first, and so the whole of the back length is effectively the lip. Dave