Floating Resin For Hard Baits

[RayburnGuy]

What hooks did you use for your calculations Dave? The short shanks are really popular these days as they allow you to go up a hook size without drastically changing your weight.

 

The above suggestion is about the limit to my contribution on this subject, but like Mark says, "I love it when you guys talk dirty".

 

Ben

Edited April 10, 2015 by RayburnGuy

[Vodkaman]

The biggest hook I have is a #4 EC-777 and I have that modelled up.

 

The only other hook I have is a VMC barbarian-6 with the external barb.

 

I only fish small baits and so have no need for anything bigger. Bawal is a pirahna type fish with an extremely strong, small mouth.

 

We just wanted to give you a taste of our design process, as we have worked together on many projects, but usually soft plastics.

 

Dave

Edited April 10, 2015 by Vodkaman

[mark poulson]

Dave,

Since you don't have hooks in the rear sections, you can get away with using spinnerbait wire for hinge pins.  I've even used small sst cotter pins for the female half in really small baits, and they work, too.

[CNC Molds N Stuff]

Spring temper (full hard) SS wire (depending on alloy) may allow for smaller wire.  Something as strong as a sewing needle would let us use very tiny wire, but I have considered that a smaller size wire might have another strength issue.  Stresses on the bait that get placed on the pin will be on a smaller area of the resin.  Forces will be more concentrated.  

 

We are trying to model a bait with more durability than the bait that inspired this session.  That was my first focus.  Dave believes he can also add to it so the action is better and more consistent.  We are having to compromise in many areas.  

 

We may post some pretty pictures later.  

[CNC Molds N Stuff]

#2 Daiichi 4X Strong Wide Gap is apx 1.32 grams.  I weighed five of them at 6.6 on my little resin scale and divided by 5.

 

#2 Excalibur TX3 (same point spread) is 1.12 grams.  Weighed the same way.

 

With either hook I would add .05 to .1 to calculations just to be on the safe side.  

 

I've got to run, but I'll get you some dimensions later.  

 

The other hook I would like to consider is the Daiichi Death Trap, but I am out of them right now.  

[RayburnGuy]

Don't forget the split rings. I've built a couple baits that the weight of a split ring determined whether it was a slow floater or slow sinker.

 

I look forward to seeing what you guys come up with.

 

good luck,

 

Ben

[Vodkaman]

I agree Bob, the bearing area of a finer pin has been niggling away at the back of my head.

 

The hollowed out first two sections has helped a lot. The buoyancy of each individual section is as follows:

 

sec1 = -0.16g

sec2 = +0.85g

sec3 = +0.35g

sec4 = +0.04g

sec5 = +0.17g

 

A total buoyancy of 1.25g which is 8.4%. Section 1 is still a slight sinker, this is because it carries the hook and the largest pin. Still the larger hook and a top coat to come, but it is looking good.

 

Dave

[Vodkaman]

The 1.32g hook made a slight difference: sec1 = -0.3g, but overall = +1.11g so still good.

 

Ben - yes, split rings are in there.

 

Dave

[mark poulson]

Dave,

I think the only time you would have to worry about hinge wear is if you're building a trolling lure.

It would take a lifetime of casting to match the wear of one day's trolling.

[flyonline]

How about roto-molding? That way you can pick a stong resin but still keep it light.

 

Fairly simple for the home builder too I would think.

 

Steve

[Vodkaman]

Mark - you are right of course, plus I keep forgetting that everything beyond the first section is just wagging, no hooks, no load. BUT, the same is true for the Kicktail, whose well documented failure problems kind of inspired this project.

 

What causes the KT to fail, and by all accounts quickly and frequently.

 

All I can think of, is perhaps insufficient rotation at the first hinge. The lure then getting flexed beyond its designed movement when battling a large bass by its celebrated head shake thing. With this in mind, I have designed the lure with a much more robust hinge using the full depth of the lure for the hinge mechanics rather than the small centralized hinge of the KT.

 

This has an aesthetic fall out, as does designing the hinge with a half angle rotation of currently 65 degrees. At full rotation, this fully exposes the hinge which are never pretty in the best of circumstances. So my personal goal was to design a robust hinge with some sexy curves and angles, to at least try and rescue some aesthetic points.

 

If this was a hand made lure, the hinge would be something tedious that you just want to get out of the way. But designing on CAD, a hinge that is going to be machined to the same accuracy as the design, is a unique opportunity. I'm just glad I don't have to make it

 

Dave

[barrybait]

I didn't completely understand your hinge design but want to throw in the idea of a carbon fiber pin similar to that used in Wake Jr. wake baits.

[Vodkaman]

Barrybait - thanks for the suggestion. I have not heard of carbon pins, they would certainly be buoyancy friendly.

 

We are trying to keep this lure to local store off the shelf components.

 

Dave

[barrybait]

I understand.  Probably not at the local hardware store but easily purchased at McMaster Carr  $12.18 US plus shipping for 48 inch long, 1/8 dia shipped worldwide I believe.  McMaster-Carr catalog, raw materials, carbon fiber, rods.  Do-able if it helps you.

[Vodkaman]

The problem is the 1/8" diameter. The image below shows a circle 1/8" diameter, the solid circle is the 1/16" pin that we are currently using. Even 3/32" is too large, making the walls too thin.

Dave

[CNC Molds N Stuff]

Garolite and Carbon Fiber to 1/16 is available.  Don't know much about Garolite.  

[Vodkaman]

Bob - D1/16" carbon fiber works for me, it has increased the buoyancy to a very healthy 2g or 13.4%

 

Unfortunately, because we have removed all the weight from the back end, the lure now floats nose down 32 degrees. We are going to have to put a gram of that back into the second section in the form of ballast, to pull the nose back up.

 

I think we should stick with the D1/16" steel pins and keep the carbon pin as a backup if we need it. Even with the steel pins, the lure floats nose down 15 degrees and I have positioned the hook as far back as I can.

 

Of course, these angles and buoyancy numbers are all theoretical and serve only as a rough guide. We have to build one and see. At least now, we have a few backup strategies; foam inserts, carbon fiber pins, extra micro-balloons, hollow cavities.

 

The design as it stands at the moment is about as simple as it gets; no fillers or extra ballast required, the No2 hook serving as ballast. The steel pins in the rear sections have the effect of keeping it all fairly level. section 2 is a tad buoyant at 0.85g but the rest are fairly neutral, with an overall buoyancy of 1.2g or 8%, most of which will get used up by paint and a top coat.

 

If you are happy with the shape, I suggest we freeze the design and build one. Any modifications will not affect the machining, being filling additions.

 

Dave

Edited April 11, 2015 by Vodkaman

[mark poulson]

Dave,

You mentioned the Kicktail lure.  I fished one, and it broke.  It was made from a very brittle plastic.

Were I to design a bait for production, I would first fashion it out of whatever I could to make it work.

That way, I could work out all the kinks, and then it would just be a matter of reverse engineering it, and finding commercially practical substitutes for my hand made prototype.

But I have never designed a bait for production, so what the hell do I know???!!! Hahaha

[Vodkaman]

Mark - This lure is certainly not pretty enough for production. Bob just wanted to have a go at cutting one for his own use, for interest as much as anything. I jumped onto the band wagon because the project was an opportunity to design a swimbait for machining.

 

There are limitations, machine time is expensive, so you don't want to be designing for a 5-axis machine. The main limitation with 3-axis, is that you cannot do undercuts, so blind hinges are out of the question.

 

If I wanted to do a bait for production, I would design it for hot plastic injection and use my China contacts to find a manufacturer. I would prototype using a 3D printer service, to make sure the bait swam before committing to manufacture.

 

For a low volume pour, I could probably get a mold cut here in Bandung. There are a lot of engineering shops around the city and labour costs are very low. If this bait swims any good, I might just do that. Depending on how the bait looks, the design could be adapted for other fish patterns; perch, crappie etc.

 

I doubt that I will be getting too many contracts for this kind of lure design. A lot of hours involved, so a fat wallet capable of dispensing 4-digit numbers would be required. This is not a paid job, Bob and I are doing this one for fun.

 

Dave

[JRammit]

Im not advanced enough to take a shot at any type of jointed lure yet... But i was wondering... Why couldnt u take some tieable wire used for leaders in pike/musky fishing, and use as through wire?... Maybe loop it inside so u have 2 points connecting head to tail... No need for hinges or pins.... Just a thought

[Tim2199]

I watched a interview with Mr. Hudleston, and he actually desinged on one of his early hard swimbaits with braided stainless wire. Now it might be different on a bait this size, but he found on his larger bait that the leader-style wire broke down prematurely with the flexing inherent to the swimming action of his particular bait. I was thinking about trying this design too, but his results confirmed my suspicions that the braided wire might not be the most durable option on a larger swimbait.

[CNC Molds N Stuff]

Dave,  

 

Using more than one type of material for a pin is not unreasonable if it helps with balance.   

[Vodkaman]

Bob - that would work. Carbon for No1, the longest, steel or brass for the rest.

 

JR - not an unrealistic suggestion and one I have played with before, using a nylon thread. With swimbaits, total freedom at the hinges is most important and the biggest cause of failures. I feel that the slight resistance to bending would be enough to kill the action.

 

Dave

[CNC Molds N Stuff]

I think we are at the point of testing.  I'll cut one when I have a chance.  (I've got orders stacked up, but I might get my Taig going again just for personal projects.)

 

Might be a while.  I'll email you some questions and particulars Dave.  

 

I think I will go with your in mold plunger idea.  I've got to pick up some large reamers for some other stuff.  No reason I can't use them for this too.  

[Vodkaman]

Bob - I am seriously considering getting one cut from this end too. I have emailed out a couple of feelers and have prepared a mold model for discussion for when I can set up a meeting.

 

I have also prepared a model rotated into the XY plane for you that I can send when you are ready for it.

 

I think venting is going to be a big issue with this job, as the resin is relatively thick compared to your usual medium of hot plastic. I have opted for a blade venting system, in the hope that the resin will be too thick to enter the vent channel, thus minimizing the trimming operation.

 

The blade I have used is 0.1mm thick (0.004") is this too thick or thin?

 

I have vented every conceivable air pocket, so I certainly do not want to make it too thick.

 

I am not trying to do your job, but I want something to play with this end. The postage system is very expensive and customs are a nightmare. They will want their slice of the pie and are going to ask all kinds of questions about why I have bought a production mold. This is why most distribution companies will not deal with Indonesia. Things have improved here, but corruption is still rife.

 

Dave