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Floating Resin For Hard Baits

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Are you back in Indonesia?  I had thought you were in China now.  I have not shipped any molds to either of those locations, but I have not had any issues shipping to various countries so far as long they are not on the State Department restricted list.  Since all of my stuff is low pressure its not restricted otherwise.  Its all EAR 99.  

 

Since we are looking at a (semi gravity - semi injection) with pressure hold I think ANY vent may need some trimming or filing.  Of course it will need venting.  I tend towards point vents trying to predict where air will pocket and get trapped.  I typically run .003" depth vents on one side, or .002 on both sides (.004 net) if its a tough spot.  You are in the right ballpark for depth.  

I have no clue about the viscosity of the resin, but I can tell you that different resins can run the gamut.  I work with Flex coat and 5 minute epoxy for example all the time now.  Flex coat paints on nicely with a flux brush, but 5 minute applies like a very thick syrup.  It flows, but its easier to apply for somethings with a stick instead of a brush.  

 

I'll see what its like when I get some.  

Edited by Bob La Londe

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I will take the blade down to 0.002 and see it this works, maybe a touch thin, but the blades are several mm wide.

 

Yes, back in Indonesia now.

 

Dave

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What about manipulating the pour by pouring straight resin when needed and resin w micro balloons when more buoyancy is called for?

Edited by FrogAddict

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great read guys, don't appreciate the exact stage you are up too or what final decisions you have made but would contribute the following if it helps,

 

1. Smooth-On Foam, that have a foam which has density 416Kg/m3, haven't seen that mentioned before in this thread. I have tried this alot in my adventures, provides a good density, skins well and fairly easy to use. Problem I found with it is that when it gets hot that foam softens. I stopped using it due to that reason. Not suitable for lures which sit on the deck of a boat all day. I finished a couple to see how bad it was, I left my lures in the sun for half a day and in the end could bend the tail half way to the nose of the lure. Contacted Smooth-On and was told that what I observed was to be expected.

 

2. Featherlite, I have found it OK as standard but I probably wouldn't trust it completely. For my application I needed to add more micro balloons to the featherlite and that just compromised the strength way too much. I am currently working on an alternative as a result. My lures are for northern Australian fish which can really work a lure over. While my lures were thru-wired, I found two main issues with the featherlite, first was cracking around the tail section about 10mm up from the rear hook hanger and cracking around the bib slot insertion point. Both were at least 6mm thickness material but still broke under both fish pressure and what I call racket abuse.

 

Main issue I found was the weight of the hooks and split rings meant I had to compromise the resin too much. I was targeting neutral buoyancy, the added weight of two split rings and #2 hooks contributed 4g to the total lure weight. Additional compounding of this is that the featherlite needs to be pressure cast in my view to ensure no bubbles within the structure. I have tried without pressure casting and while the final resin density is reduced, I found the foaming effect created yet further weakness in the resin.

 

Great read, good to see you slowly sorting things, looking forward to seeing the final result

 

Angus

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Angus - thanks for jumping in with this quality contribution.

Where we are at the moment, is that we have a design that will support the 4g of hook hardware that you mentioned, plus a little bit extra to support a top coat and still get close to neutral buoyancy using the standard Feather Lite product, without having to add extra micro-balloons.

I agree with your assessment of the Feather Lite product. Just looking at the manufacturers data provided by Smooth-on, the resin is significantly lacking in strength.

It is up to Bob as the machinist, but the intention is to cut a first prototype mold and build the thing. Do some destructive testing and see exactly how bad it is and try and figure out what can we get away with using this material. The prototype will also get some field testing in the real world too.

If we find that we have not significantly improved on the KT lure, then it will be back to square one for another go.

The densest foam on the market would be my next consideration. The advantage of this material is that it is much more resistant to shock loads, which is where Feather Lite falls down.

There will be considerable re-design to account for the buoyancy of the material and the ballast requirements, but this is a good thing, allowing me room for manouvre which I did not have with the FL product.

My main concern with the foam is bearing strength. How much material do I have to put around the hinges. I want to keep this number as small as possible and still keep the lure safe. This is going to come down to building test pieces and destruction testing.

Yes, we can overkill and put extra material, but it just looks ugly.

We are planning to pressure mold the FL product by injection. This is the only way we are going to fill all five cavities in one hit and get rid of all the air pockets. The injector will be built in as part of the mold.

The density of foam that you mention at 416Kg/M3 is a nice number, giving a specific gravity of 0.46 the equivalent of 28.7Lb/cuft. This is exactly the kind of material that I would be looking for. As for it softening in the sun, well this is a minor consideration. Customers will just have to learn that you have to look after this product, or go back to the KT.

Dave

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FrogAddict - Just spotted your post. Yes, the split material is an option that we have considered, but we are struggling to get the lure to the water surface with the lightest of resins and using only the hook as ballast. With a 4" lure comprising 5 hinged segments, with such small cavities and the need to inject the resin, we quickly abandoned this idea as too fiddly.

 

In addition, our primary self imposed mandate is to keep the operation as simple as possible and only use locally available components.

 

Dave

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sounds like you have it all in hand. To give you some further reference, see attached image of the bend I could put in my lures. This was not the maximum deflection but tells a story none the less.

 

WP 20141123 13 49 37 Pro

 

Angus

Edited by Mcleod

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