Microballoons, how much for ideal action?

[Papas82]

 Hi guys, new here and this is my first post. I have been casting resin lures from PU the last 3 months and even if i casted over maybe 30-40 lures experimenting with resin density, buoyancy, weight placement and amount i still face the same problem. If I retrieve very slow or just slow the lure will run ok but if I try to retrieve faster or jerk then the lure will spin around its axis. The particular lure and the shape of it is a glider and so i want it to run side to side even retrieving fast and be able to give it a push with the rod tip without any problems. I have seen many different videos on you tube and read articles, followed instructions on where the weight should be placed but still I didn't get a breakthrough yet.

From what i understand it has to do with the ratio buoyancy-gravity and weight placement.

The blank is 10cm long ( approx 4") and weights 18gr just with the screw eyes attached. There i used 15% microballoons only from part A of the resin so 7,5% microballoons from the whole mix.

Are there any guidelines on the ideal amount and ideal extra weight added according to the size of the blank?

Thanks in advance

[Vodkaman]

MBs is a difficult subject. I have experimented with and read lots of posts. I am always left with questions; the 15% that you mentioned was that by weight or volume. The second question is always what was the final density of the body material.

The big problem is always density. Resin, regardless of type, has a density heavier than water, usually around 1.2g/cm³. Using MBs will bring the density down to something workable, but the final body density will be high, leaving no room for ballast, hardware, and still ending up with a lure that floats after painting and topcoat.

The resulting lure has a very high/central COG which means that it will turn over, rotating on its long axis. Fine for slow movements, but as soon as you inject some pace with a jerk or acceleration, the fluid forces overcome the resistance to rotate.

The lightest body density that I ever achieved with resin and MBs was around 0.65g.cm³ and this severely limited the lure action. I gave up on solid resin with MBs as a bad choice. I hope someone replies with better news for you.

To measure your body density, do a search for ‘Archimedes dunk test’, this will show you how to measure density (use metric measurements only).

To prevent rotation, you either need a lighter body density or include hollow portions to reduce body overall density and ballast to provide resistance to rotation.

Sorry not to be more positive, but just trying to help with an explanation.

Dave

[Papas82]

Thanks Vodkaman, the purpose is not being positive/negative but to get some facts on the table so I have have a clue on what is going on. I forgot to mention that 15% was by weight only of part A. With that ratio the blank alone without the hardware will float. Still with the hardware on it will float exposing only the nose out of the water. I tried to put 1,5gr lead in the front and it is a slow sinker. 

So basically I shouldn't use microballoons at all then? I tried that also without any great success plus that it was sinking quite fast so I suppose that if someone want to achieve slow sink, sudpending or floating the MB are the only way to achieve it with PU?

[Vodkaman]

By weight is good, that is the way that I would do the mix.

Without MBs the situation would be even worse. At least with MBs you get a reasonable ballast effect from the hooks and hardware. Without MBs you would end up with a fast sinker that still rotates.

Your choices are:
1 - Include air pockets to lighten overall density and add ballast low down. This is obviously a more complex molding option.
2 - use an expanded polyurethane material, say 12Lb or even heavier density. This will give you a light body capable of carrying ballast that will fix your problem, and still enable you to use your mold.
3 - Abandon molding and go for wood.

Dave

[Vodkaman]

PU has a range of densities as I just found out with a Google search. If you are getting even a nose up at the surface with hardware, your PU is certainly lighter than the 1.2 that I quoted.

It sounds like you are very close but no cigar.

You could try 25% MBs but this then becomes a pouring problem as the viscosity of the mix increases. I achieved success using a cake icing injector to deliver the mix.

I am not experienced in gliders, but from what I have read; the lure should sit nose up at an angle of around 30 degrees, possibly 45 degrees. I will let more experience jump in here.

Dave

[Papas82]

Thanks for valuable info. Then I will try with more MB to increase buoyancy and be able to calibrate the ballast easier. Up to 20% it goes fine to mold but it is a big possibility that I get air sockets on the blank. Then it needs to be filled on different spots on the surface but even worse I don't get consistent result because the amount of sir bubbles varies every time. 

I will have to investigate a little bit on different products regarding density to find some that fits the description you give me. So I need something with heavier density to achieve my goal a suppose. 

I make my prototypes from wood but I don't have power tools to be able to make a batch from one type of blank and my hobbyroom is like 2×2 square meters so its also a space problem thats why I stick with PU ( for now ) since it's more convenient.

[Vodkaman]

LIGHTER density.

This will allow you to control the sitting angle for your glide. You tune the angle with ballast.

Like I said, gliders and jerk baits are out of my field, but lighter density body gives you room to adjust with ballast positions.

Dave

[Hillbilly voodoo]

There is no magic mix in my opinion and actually work up different recipes for each model of lure I make. I vary my mix to reach different actions, sink, and rise rate. I have also combined different layers in some messing around with how it effects the action 

solid resin/micro balloons baits will usually be heavier then wood baits for the most part. This will effect the action if you are trying to duplicate a wooden original. To get close to wood you have to create a thick mix. I would need to break my top water recipe into ratios when I am more awake 

When I first started working with resin/micro balloons I was trying to duplicate my wooden baits and honestly the best thing I did was stop thinking this way. I now create a mold to get the shape I want and build up a recipe of resin/micro balloons to achieve the results I want. This has given me way better results and opened up more options 

Best advice I can give is start designing baits to work with the principles of resin/micro balloons and stop trying to duplicate wood. 
 

I am on day 2 of a 6 day work set and I will be more helpful on my days off. Long work days fry my brain lol

[Papas82]

Hey Hillbilly, thanks for sharing your experience. To be honest that is exactly whst i started doing. Create a drsign i like, make a mold of that and i take the rest after. I make a lure from the mold and i experiment on that. My gosl is not to duplicate a wooden lure but to make my designs work fine and have the action i want.

As Vodkaman stated i should have less density in my resin to achieve more buoyancy so today i made the same lure going from 12% MB up to 17% and i have to say i saw enormous improvement on the action. Easier to make a lure that floats to have as starting point and then to fine tune the way you want it. 

Ftom what i understand microballoons are essential when casting resin lures even if the lure is going to be fast sink. I understood that buoyancy is extremely important in order to achieve a good action. 

Funny thing is that I had to use one liter of resin and probably one hundred wasted lures in order to understand what is going on lol

[Hillbilly voodoo]

I could have saved you the hassle of wasting 100 lures lol

without getting into it too much yes it is easier to get movement out of a lighter more buoyant lure but what section of the lure is more buoyant makes a difference too. You can achieve some interesting things 

for example you can combined the correct body shape, make one part of the body far more buoyant, and a heavier section. Do this correct and when you slack line your lure on the retrieve instead of floating up it will shoot back on a 45 deegree angle instead 

 

[Papas82]

Wow, really nice input vodkaman. That kind of " escaping rush" action when i slack the line is something i wanted to achieve all the time. The question is, which part of the body should i make more buoyant and which more compact? I assume that your point is that i make like half of the body first and then cast the rest of the body with different ratio of density?

CNC that is what i figured out. Without buoyancy there is a dead end so i condider microballoons as an essential for casting lures. I measure by weight but if i took it by volume that 17-20% microballoons is actually 50% if not more by resin volume. 50% from one part which means 25% from the total amount of resin combined part A and B.

Edited July 30, 2020 by Papas82

[Hillbilly voodoo]

@Papas82 as much as I enjoy Vodka and cranberry with some ice on a hot day I am not Vodkaman lol

I achieved this with a deep diving crankbait with a banana style body. The back end of the bait is slightly larger then the front. The mold was built so the head was poured on a downward angle. When pouring baits with resin/micro balloons the consistency is not the same throughout your lure. The low points will have a higher % of resin because it settles a little before hardening. So basically when combined a large lexan lip and the low point of the head in the mold the front 1/3 is noticeably heavy and the the bait becomes much more buoyant as you hard to the rear. The weight of the hook in the rear shifts the most buoyant section about slightly away from the back end

hope this makes sense but basically the bait has a head that heavier and the body becomes more buoyant as you get to the rear. Because the back end of the bait is actually slightly thicker the the rest of the body minus a small taper at the very end it is extremely buoyant. The curve of the body helps level the bait 

Unfortunately because I don’t use any technical formulas or proper plans it’s harder to explain how I achieve things. For the most part I just keep a note book of recipes to repeat my work. I basically just come up with an idea think about it non stop till I get around to building it and see how it goes lol

I will be converting this into a jerk bait design in the future where it would be more beneficial once I complete 2 other new designs 

Either way what my main point is there is a lot of different was to adapt resin pouring baits that are unconventional when you start playing around with the different properties of the material. 
 

hope some of my ramblings make sense 

[Papas82]

Hillbilly, sorry lol, my head is forgotten somewhere haha. 

What you say makes sense yes though for now i have my silicon mold feeding hole on the spine of the lure i am planning to cast the lower 1/3 of the lure ( belly section )pure polyurethane without microballoons and the rest 2/3 adding 17-20% MB by volume. It could be that maybe I get a balanced lure already out of the mold since the more dense and heavy part is under. Then hopefully just with minimum ballast I can finetune. I like your idea though having the front 1/3 part of the lure more dense and heavy than the tail. 

This whole casting resin lurebuilding balancing thing made me lost my sleep lol.

[Hillbilly voodoo]

I still pour into the spine it is just on angle. I have actually propped one of my mold to change the angle to test things. With the bait I mentioned the body shape plays a big roll in things too
 

Don’t worry about the loss of sleep. At some point you will loose your mind and sleep won’t matter anymore 

[Papas82]

Lol, it goes that way

[LHL]

Do you have any pictures of the lure? I've created several jerks/gliders now of various shapes and sizes but never any out of resin. A pic of the bait might make things easier to visualize. In general everything said here is spot on though.

[Papas82]

LHL yes, here it is.

[LHL]

I'm going to assume this is a flat sided jerbait. The shape looks perfect but my thought is that this being a smaller jerkbait (typically this size is seen on 150mm+ sized lures) there's not much room to add weight without going above the midline. My guess  would be to increase the height of the lure (bluegill style jerks perform much better in this compact size) or to distribute a lot more weight in very small pieces along the bottom of the lure. Again you'll be limited because it's a small bait.

[LHL]

This is the style I am refering to. 

[Papas82]

LHL correct. It is a flatsided jerk approx 4" long. In order to give it the sink rate i want ( very slow almost suspending) i don't need more than 1,70gr of extra ballast. That because of the microballoons i add. I'll do what you mentioned. I will spread the weight along the belly section and behind the belly hook.

Btw, lovely jerkbait you made there.

[LHL]

Yeah you don't have much weight to work with to begin with which makes things tricky. Let us know how that goes and if it changes anything.

 

Thanks

[Papas82]

Yes i definitely will do