[BBC]

Has anybody determined the density (bulk and skeletal) of different raw materials (cooked plastic, salt, glitter (different sizes), etc.)? I was considering doing this and then writing a program that you could plug in your formula and it would shoot out a density and rate of fall for lures. I figured this would be very helpful with stick baits and maybe a few others. I didn't want to spend a bunch of time determining densities if someone had already done it and was willing to share.

Along with that, if anybody has determined the density of different brands of stick baits this would be helpful as well. I have a few yamamoto's and kinami's that I can test but I don't have any other brands.

Just a thought as I'm sitting at my desk trying to avoid doing actual work...

Eric

[SwampBaits]

Wish I could help, but I must have missed that class in school! Sounds like a good idea if you have the time though.

[saint308]

Hunh? Saint.

[bassbug]

you need another variable, water hardness

[bojon]

WARM AND COLD WATER.Ice seems more dense,but it floats.All this is beyond me.My math teacher would be ashamed of me.

[One Sock]

too many variables, everyones recipies would have to be the same, you might be bale to determine with an approx density, but never exact as there will almost always be a differnce in salt content from first stick to last, one might be slightly more than another depending on pouring methods

Then not only the water variable but also the line and hook being used to fish such bait. You should see the difference in wiggle when fishing a GY on 4 lb test as opposed to 20 lb braid also the difference when using a 2/0 ewg as opposed to a 20 octopus hook, you can get free fall rates by dropping your baits into a swimming pool and comparing them to others....

Really want to blow your mind.. buy 4 or 5 packs of hand poured sticks on e-bay. not only compare them to each other when dropping them in the water, but compare them against their own, take two sticks from a 50 pack of almost any hand poured bait, and I will almost guarantee that the fall rate is not identical. i have done enough research on this, from stirring after pouring every two sticks, from pouring at 375 degrees as opposed to 350 as opposed to 325 and so on and so on. it casn be mind boggling, weight your sticks on a gram scale after making 50 -100 you will find a bunch do not match up exactly. it's very interesting stuff. It's why you can't sell sticks on e-bay for decent money anymore, too many people who could give a rats ass how they fish that are making sticks.

want to make premium stick baits? do your homework and experiment, you will also come up with some phenomanal colors :-) and always write everything down. I have a bunch of fantastic sticks made at 3 am that I have no idea how I made them :-)

[BBC]

ok...I think you guys missed the point. I already have a formula that I like to use. However, every customer wants a rate of fall like a certain brand of lure that they like to use. So, if you knew the density of all the raw materials you are using (mainly the salt, plastic, and flakes) and you knew what the density of the lures you typically make is, you could write a program (like make an excel spreadsheet) that would calculate how much salt/sugar flakes you needed to add or take out of a recipe in order to achieve the density of a certain brand. It would ultimately take most of the experimentation out of the equation. The main reason that I want to do this is because I've been making a lot of custom colors for some of the local FLW guys and their colors have 3-4 times the glitter that I usually use and it's messing with the density and stiffness of the sticks. So, I need to back off the salt and sugar flakes to account for this and add some more softener. If you had all the data before you started, you could get a very close estimate of how much salt and sugar (and if you wanted softener as well) you would need before you even made that first batch.

Rate of fall would be determined empirically (through experimentation) using standard brands and your (or my) typical recipe. It would only be good for the specific lure (shape and size) that you tested. I understand line, hooks, and weight play into this but you would assume the customer is using the same set-up with your lure that they used with the other brands which takes those things out of the equation.

Sorry if I'm taking this too far for most of you guys but this is what I do for a living (chemical engineer). We do this at work everyday with our products and it saves us millions of dollars because we can optimize formulas with a computer and do a couple experiments instead of experimenting until you figure out where you need to be. Experimenting costs a lot of money. If a computer can get you in the ball park, you can wander around until you find your seat. Otherwise you have to find the ball park first.

Eric

[saint308]

Hunh?

No just kidding. That sounds like an interesting idea. I hope you figure it out. Saint.

[Vodkaman]

BBC. It sounds very do-able to me, well at least to get in the ball park. Reading your post again, I am assuming that you have written the spreadsheet and it is working out OK.

My problem is measuring the volume, which will obviously be part of your calculations also. I can get close with jars and tubes, so how are you doing the measurement, or are you using lab equipment. Can you suggest a home made aparatus.

This requirement would help in the hard baits section also, as they often play around with zero sink rate lures. This request is not a hijack attempt, I think it is valid and relevant to the subject.

[BBC]

Vodkaman,

I do have the spreadsheet written (I wrote it while I was eating my lunch at work a couple days ago). I am planning on measuring densities this week.

For things like salt and glitter you need a bulk density and a skeletal density to make the calculation work unless you were measuring them by weight when you were making the lures. I use measuring spoons for my glitter and salt so I need a bulk density (which will give you the mass of the glitter or salt per volume before it goes into the plastic). Bulk density is easier to measure because it includes all the air between the flakes of glitter or grains of salt. To make the calculation accurate for the final product you need the skeletal density (the density of just the glitter or salt and not the air since the air is not in the lure. those voids are filled with plastic which is another part of the calculation). I will be using lab equipment to measure the skeletal densities which, as I said, is only necessary for the dry materials. Then you just need the density of the plastic (after it has been cooked). Then you use the mass law and densities to 'predict' the density of your final product. Then, since every lure of a given style will have the same volume, you can do quality control by weighing lures at random throughout the lure making process (which some people already do).

I'm not very familiar with the process/materials used for making hard lures so I couldn't give you a direct answer for a home made apparatus for your purposes. I will assume that you are using a certain type of wood for all your lures and you have standard lure styles (size and shapes). In which case you could find the density and volume of the body of your lure. That is where I would start. Then, as you drill holes for hook hangers and weights you would be replacing the wood with a metal and would have to take the differences in densities into consideration.

I think it would be very valuable to know the density of everything you are using and then you can make trade offs with materials (and the size or amount or weight you want to use) until you achieve the density of the final product that you are looking for. In my case, the salt and glitter add weight to the plastic (which will float naturally). So, knowing the density of everything I can calculate home much of everything I need to add to get a density within a certain range.

If you give me some more details I can get more specific with how to measure the density of your material and try to help you find a way to measure this with ease and precision. Feel free to pm me if you prefer, or we can continue this thread.

Also, I'll keep everyone updated with my findings as I continue my little project.

Eric