Vodkaman

Looking good. More, more, faster, faster!

RTV is expensive, but that is only enough to make one 2 part mold. Do you mean one pint of each of the two part mix. If so, that is a bit better. I buy mine at a local craft shop. Handy but expensive, as all craft stores are. It was US$153.75 for 19lbs total, that works out at US$8.09 per pint. Usually when you buy small quantities, you pay a premium price, but that does sound excessive. I suggest you search TU, collect all the company names that do the stuff, go get the prices off the web sites and compare.

King. Rather than struggle on your own, you should post your problems, that is part of what TU is for. You would be doing everyone a favour. Others will learn. Often it is the little things that can make a difference. These are so small, they never get mentioned. Such as keeping a favourite mixing container, one with rounded corners. You can get your fingers in there and no powder gets missed. I use a 1.5 ltr icecream container. Always mix next to the sink, makes clean up easier. NEVER pour unused plaster down the sink. You'll only do it once. As you make more, this library of knowledge builds and the operation slickens. At the start, write the amounts of PoP and water that you use, so when you get a good one, you will be able to repeat the feat. I'm new to it all myself, so I don't have many tips to share, but all that small tips stuff would add up and make a difference.

Personally, I don't fish, so hopefully I can save everyone else some fishing time. Everything you have said is true and because of all the inputs and variables, we can only expect to get reasonably close. Every measurement has errors and these will accumulate, so don't be expecting majic, just close. Adjustment on the bank would still be necessary.

excellent job. Because PoP is so cheap, many people may be thinking that it is a second rate mold material. With your professional seamless baits, I think more will now give it a try. I personally did not have much success with hard baits. The "hard mold - soft bait" rule is very relevant. I will have to try with the resin, it is not as sticky as foam (disastrous!).

Pete. That, plus the photo of the brain surgeon at work.

Clemmy, you are on the same wavelength. Yes, the epoxy and paint will be a before and after estimation. So the builder will have to finish one first, to extract this infomation. Extra entries will be built in for foil and fins. If not used, just enter zero. Shortlite, I am thinking of a components database too. But, the builder will weigh a number of hooks, type in the weight and the number that he weighed. The spreadsheet will work out the volume of the hook etc. The same for split rings, quick releases etc. This would take care of variations between hook types. This would only have to be done once for each item. I will add extra lines that can be defined by the builder. Lips will be dealt with by material type. The builder will enter the weight of the lip against the material used, also the thickness and a rough estimate of percentage glued in the body (10 -20%), this should get us close. I am planning on including water density, for the salties. It will also allow those that are concerned enough about water density to still play. I'm sure I could do something with temperature too. The spreadsheet is not just about suspenders, it is designed for all types of lure and will help to achieve repeatability between lures. The builder enters a percentage that represents its buoyancy. The builder enters 100% for a neutral buoyancy, or 95% for a slow rise, 105 for a slow sinker, and so on... I am accepting any suggestions, but the danger is making the thing too complicated, seeing as it was developed to make the job simpler.

Shortlite, thanks for the PM and for the comments above. PM your e-mail and I'll send a copy. The spreadsheet is not finished completely yet and is not of any real use. When finished, it will take into account the lip, all the hardware, paint and epoxy. I believe even paint will make a difference. The epoxy is the tough one, as it will be down to the builder to be consistent in the application. The aim is to be able to determine the ballast and fit it with confidence early in the build, with no further testing required. Well, you have to give yourself a challenge. Appologies to Carpoleo for all the tech talk, but you just might end up with something that helps.

I didn't get one. Probly read one of my posts and thought "forget it".

Ferg, no problem, PM me your e-mail. This vid is based on my earlier post. It's just a demo, not a teach-in. It may answer a few critics. There again, it may not.

I too just wanted to turn one or two, without wanting to sort out a proper turner at this time. My drill is a very cheap variable speed drill, so if it burned out, I was not particularly bothered. It was difficult to regulate, but once I had it set, I just switched on and off from the wall. It did work, but, as stated in this thread, the windings did not like it very much. But it only has to survive 30 minutes. I would not leave it alone in the house though. But if you are going to turn more in the future, you should sort a proper turner out.

Shortlite. Welcome to TU. No feathers ruffled here. I agree with all that you say, it's all about the volume. I just didn't manage to get it down on paper very well. I have written another explanation, but the pictures and/or the PDF's are too big and I don't have the tools to fix this problem, as I am in work at the moment. I will re-post this evening.

I will try really hard to come up with a simple explanation. You should know by now that explaining is not my strong point. Mark, correct.

Ferg, really sorry to hear that the "Quap P" is being such a pig, the learning curve can be a tough road. I do hope this stressful experience does not dampen your enthusiasm too much. As you stated, you are committed now and must push forward to the finish. You must give priority to the lure in question, but are you considering a second backup? Only you can decide if there is enough time for that. I've never made a large musky bait, but I know enough to understand the work involved. If I was the recipient of such a personalised gift from my son, I would be absolutely over the moon. It would be perfect, regardless of what you think. Often we are far more critical of our own work, this is a good thing. I wish you good luck completing this project and hope you enjoy the weekend.

It will probably seem bigger, but I'm sure you will be able to handle it OK.

Jim. It is not just about the weight of the balsa that you drilled out, which is very small. I'll try to explain. Don't worry about the sums, it's the answers that tell the story, but I cannot think of a simpler way to explain about external and internal ballasting. Consider a balsa body 80mm in length. By suspending in a jug of water, it is found that 19.4gm of external lead was required to achieve suspension. The body weighs 3.0gm. The density of lead is 11.389gm/cm³. From the above known information, it is now possible to calculate the volume of the body: Volume of lead = weight / density = 19.4 / 11.389 = 1.7034cm³. Total weight of body and external lead = 3.0 + 19.4 = 22.4gm. Because this weight resulted in suspension, then the weight of water displaced by this combination of body and external lead (22.4gm). 1gm of water has a volume of 1cm³. Therefore, the body + external lead has a volume of 22.4cm³. Therefore the volume of the body alone = (volume of body + external lead) – (volume of external lead) Volume of body = 22.4 – 1.7034 = 20.6966 = rounding off to 20.7cm³. This means that the volume of the body and internal lead has a volume of 20.7cm³ and when suspended will weigh 20.7gm. But by fitting the external lead to the inside of the lure, the ballasted body now weighs 19.4 + 3.0 = 22.4gm. This is 1.7gm too heavy. This has not taken into consideration that you have drilled out a cavity for the lead and in doing so, removed buoyant material. This makes the situation slightly worse, as there is less balsa to support the lead. In addition to this problem, we then slap a coat of D2T over it all, which has a density of 1.17gm/cm³, which is heavier than water. If this method works for you, I have to assume that you are doing something extra or different, making an allowance somewhere along the line, or I am making a huge error in my thinking somewhere. No one can argue if you say it works for you, but these figures are pretty hard to argue against too. The purpose of attaining neutral buoyancy is not to demonstrate to the fish how much effort we have put into catching him, but to stop the lure bobbing to the surface or sinking like a stone, when we pause the retrieve. If the lure rises or sinks slowly, surely we have achieved our goal. The tolerance required for close to true suspension is approximately 1/100 of the weight of the lure. A lure weighing 20gm needs to be built to 0.2gm accuracy. With some planning, this is just about possible. To control suspension to a depth is probably ten times tighter, 1/1000 of the weight of the lure. This is just not possible without specialist equipment, in any case, you would be at the mercy of temperature fluctuations and water purity. If the tolerance is widened still further to say ±0.5gm. the result would be a very slow rise or fall, which is surely acceptable for the purpose. I don’t do these calculations every time I build a lure, I only do them once, in a spread sheet. Next time I just do the external lead suspension thingy in a jug of water, weigh the body and lead and type the weights into the spread sheet, which tells me how much lead and how deep to drill my hole. This gets me well within a tolerance of ±0.5gm and works for me. As a post script. With the information gathered above, it is now possible to calculate the volume of the body alone, by subtracting the volume of external lead from the volume of body + external lead. Simple, no jars or pitchers AND much more accurate.

Diemai, I like it. This theory should be easily tested out, when I catch up.

Husky, no luck with the link, I'll try again tonight. I haven't studied swimbaits yet, they are my next project. But I have been collecting ideas. There are three possibilities (in my head): 1. Vortices, forming across the back, in a similar fashion to lip vortices (Many of you may not like the idea of vortices and are probably tired of reading this word, but they are a fact of life). 2. Aerodynamic type forces. The smooth flow past the sides of the body, draws the sides to swing out into the flow. One side is always going to be slightly stronger than the other and will swing out. It does not explain how the lure swings back. I thought maybe it stalls (like a wing stalls) and the suction collapses and the body swings back. Inertia carries it past neutral and the process repeats on the other side. I built a lure to explore this idea, more curvature on one side. It did not waggle and just took off at an angle. But I cannot discount the theory yet. 3. A combination of the above. The aerodynamic movement reaches a stall and vortices are created over the back. This vortex draws the body back to neutral, but inertia of the movement carries the body past neutral. The vortex fades and aerodynamic forces continue to pull the body now in the opposite direction until it again stalls and the process repeats. Now that I have written it down, the combo theory looks very promising. The problem is how to prove it. The best indication of the forces acting on a body, is how the body reacts to those forces. For example, if the bait has excessive rolling action, this would indicate to me a vortex across the back, causing a rotation. If the lure wiggled without roll, this would indicate aero theory. If the lure wiggled with a slight roll towards the end of the cycle, this would indicate combo theory. As stated above, it could be the hinges, or something we have not considered yet.

Nova and Willie have comprehensively covered your question. I would add, that seeing you are making the molds yourself, why not introduce a larger pouring cone or funnel. This will allow you to pour extra plastic, which will get drawn down as the plastic cools. This will simplify the pour and eliminate any possibility of cooling cracks. From reading your post, I assume that you are drilling your pour hole after making the mold. There is nothing wrong with this, I suspect most construct molds this way. I mold my pour holes and vents with rolled plasticine, before pouring the PoP. I find it simpler and less nerve wracking than drilling.

It has bags of character, it looks alive with the eyes and mouth. my suggestion is Mr Angry or stubby shark.

Works for me. I'm still serving my apprenticeship. Hopefully I will make some water time soon. Congratulations on your lure success.

I haven't a clue what you are asking for or doing with them. Intrigued enough to ask though. Could you please explain a little more? Thanks.

A picture of the mold and bait might help people see the fault. My first thought, is the end of the tail vented? Without an air vent, as the plastic is poured, the air in the thin section cannot get past the plastic and has no where to go. If this is confirmed as the problem, the solution is simple and the existing mold can be fixed.

That is what I did. I used an old calor gas, 15Kg. You would still have to get involved with pressure control and water traps, but I really know very little about these to help you. Good luck and report back.

The compressor can be used, I did the exact same thing some fifteen years ago. The air from the compressor will be too rough and uneaven to drive the brush directly. You need to use the compressor to fill a reservoir, a large gas cylinder. The reservoir feeds the brush with a smooth, regular supply of air. As for the required connections etc, too many years since I was involved, but should not be too difficult to find out. From previous posts, I believe many of the mentioned large American stores stock all this stuff.