How to estimate weight needed?
13 replies to this topic
Posted 15 April 2008 - 03:45 PM
I would like to estimate the amount of weight needed for a 2 piece balsa bait. I want to place weights in the body prior to closing up. How can I do this with the wood unfinished?
Posted 15 April 2008 - 05:22 PM
I assume , that because you have a jointed bait of balsa , you won't rig it with screweyes but with a through wire harness .
If I want to determine about the neccessary weight to be placed into a wooden lure , that is rigged with eyescrews , I would first apply two coats of ordinary clear laquer , pre-assemble lip and all hardware and then test the lure in my bathtube , I'd tape some leadshot , sinkers or folded roofing leadsheet to desired location onto the lure , and then I fool around with it until the right amount of weight at the right location is found , to provide best lure-action .
After I drill holes at these determined locations of the lureblank and set in the weights with epoxy glue , for the final painting I just sand over the clearcoat , that is only meant for preventing water sepage during testing , so that following paint coats adhere better .
But if you have a through wired lure , things are not that simple , because the slot at the belly is somehow disturbing .
There are three ways to proceed now :
Also clear-coat the inside of the slot against water sepage , set in the harness only temporary and push pieces of lead sheet into the slot after the wire , test again in water for action and to determine weight .
It doesn't seem to be very practical to paint the slot inside to me , in fact I never did it this way , just an idea .
Second is to really estimate the weight required and it's location and glue leadsheet into the slot together with the wire , but it would take some experience to hit it right , I have done this on two lures recently , and they didn't turn out too bad .
The third possibility is just to place your wire harness quite "high" inside the lurebody , meaning , more towards the back of it glue it in and again clearcoat your lure for testing . Now , that you have put the internal wire harness further away from the belly of the lure , you gained space for drilling leadholes , even through the cured glue inside the wire slot .
This last one is my prefered method , but your balsa lure would probably require a lot of weight , since it's that buoyant , it depends on it's size and how deep it should run .
Good success with anything , that you're up to , diemai;)
Posted 15 April 2008 - 08:12 PM
It's not an exact science but I decide how heavy I want the lure to be when finished, then work backward from there. For instance, Say I want a 2 1/2" balsa baits to weigh about 1/2 oz when finished. Heavy enough to cast well, light enough to have good action. Cut the blank, shape it/sand it, split it, waterproof the halves, and then weigh the blank, wire frame harness, and lip on a digital scale. Say all of that weighs about .20 ounce. From past experience, I know the epoxy to rejoin the halves plus the finish will total about .10 ounce, so that leaves .20 ounce of ballast to make the bait 1/2 oz.
If you plan to make other baits in the future, a small digital scale is a great tool. I weigh the components and the finished weight of every crankbait I make and record it in a notebook along with traces of the body and lip shapes, notes on the build details, paint colors, size hooks used, and any later performance comments. That way, I develop a good feeling for how much various components weigh and I can reproduce a crankbait accurately at a later date, far after I've forgotten "How did I make that one 9 months ago that catches fish so good?". You can get a decent chinese digital scale on Ebay for about $25 delivered that will weigh stuff down to 1/100 ounce.
Posted 16 April 2008 - 12:51 AM
@ DougL58 ,
"Uuups":huh: , obviously I was a little confused about your "two-piece" lure in my first post here. Thought you meant one with two sections , that's why I keep writing about a "slot" all the time , sorry .
Such comes if one sits on the screen half asleep in the middle of the night !
Anyway , but my third suggestion works on such wooden lures put together of two halves pretty well , I just recently finished a batch of crankbaits that way .
But the method of BobP is very useful , especially when reproducing certain models in larger quantities , which I usually don't do .
Posted 16 April 2008 - 01:15 AM
diemai, my average batch of crankbaits is about 4 I hand finish them and to me it's no fun to have a big bunch of crankbait blanks sitting on the bench, knowing I have hours of shaping and sanding in front of me. So I'm strictly a hobbiest. Nonetheless, I often want the ones I'm building to conform to the most successful patterns I've built in the past. And when I experiment, I like to start with a "known good" design and make changes from there. Ergo the notebook and scale.
Posted 16 April 2008 - 02:02 AM
@ BobP , I usually make about six to eleven lures in one batch , but most likely all different ones , only if requests of friends occur , I'd carve some lookalikes , but not more than five together , it's too boring for me to always reproduce the same models .
On the other hand , if I managed to design a good lure , I ought to have more of them , for friends and in case of loss .
My batches consist of that certain amount of lures , just because not too waste the mixed epoxy finish , that I mix in small medication cups , these are very handy for such , 'cause they already have scale marks for accurate mixing , and one mixing process is just enough for that certain amount of lures .
I don't utilise that method of scales and keeping records , only have sketches of my lures for shaping them alike .
I am kind of lazy to do that scale thing , though I surely see point in it , even also for small amounts of lures it makes things easier .
But even if I would do so as well , I won't feel good to rely on it , I have more confidence in those tests in the bath-tube .
But like with so many others things, there are different ways to achieve something , it's only a matter of personal preferrence .
regards , diemai
Edited by diemai, 16 April 2008 - 02:04 AM.
Posted 16 April 2008 - 06:21 AM
I obviously use the scales method, but due to slight variations in the wood, if you are going for a suspending lure, fine tunung will always be required. But for regular lures the scales are perfect, you can find the ballast value to achieve the flotation you want when the blank is shaped.
By accurately weighing the blank and weighing the pure lead required to suspend the blank, enough information is gathered to calculate the ballast. I have written a spread sheet to perform all the calculations, I just enter the two figures and read off the answer. If I enter the drill diameter, it even tells me how deep to drill the hole.
other information given by the spread sheet: volume of the blank, density of the blank (plus sealer), final weight of the lure (approx). The spread sheet allows you to enter the amount of buoyancy you require, I usually go for 90% - 95%, this means that 5% - 10% of the lure mass will be above the surface. I will be enhancing this spread sheet to include entries for weight of lip, hanger, hooks and eyes.
Also, the sheet can by made to give information at later stages of the build, before epoxy and after epoxy. For future lures, you will be able to closely estimate the effect of the top coat.Hell, it is even possible to enter the depth you require the thing to suspend, but where do you draw the line.
If anyone would like to try the system out, just PM your e-mail addy and I will send a copy.
Last weekend I had seventeen balsa blanks on the go at once. It was soul destroying with the amount of work in front of me. I even split them into batches so I would not have to look at them all at once. This is by no means essential kit, in fact the same information is
9and should be) gathered during and after the first build, for future reference. The sheet just allows you to get close with the first one with confidence.
Posted 16 April 2008 - 06:37 AM
Does it also factor in air temp humidity and wind direction?:huh:LOL Sounds like you put a lot of work into it.
Posted 16 April 2008 - 06:49 AM
Gee Dave - I will have one of those when yo are back on deck . pete
Posted 16 April 2008 - 08:45 AM
Thanks Guys... Vodkaman, your calculation spreadsheet sounds very interesting. I'll send you my email addy. I am working on my first bait. It is a swim bait, bluegill. Body is about 6". It is in 2 halves now and will have 2 sections. Tail section is already cut. Still working on the fins. Ribbed and flexible. I want to add weight before I glue the 2 halves together so I want to calculate the amount needed as close as possible.
Posted 16 April 2008 - 09:02 AM
For a first bait, that is awesome. I have made several and cannot come close to that one. I am intrigued by the material you have used for your fins. Would you share what it is? Might solve a problem with a swimbait I have been working on.
Thanks and good luck ( as if you needed it )
Posted 16 April 2008 - 05:13 PM
Should have mentioned from the start , that you are into a swim bait , would have kept my big mouth shut , these are above my standards:( .
But I have already made a design sketch of a three-section-bait , gonna start cutting out these days , just ought to try it , too:wink: .
regards , diemai
Posted 16 April 2008 - 07:11 PM
I've sent the spread sheets out. If you did not receive yours, PM me, I had a problem with one address.
PS. I should have stated that the lead in the suspension test should be pure (not an alloy) and mounted externally, I tie mine to the body with sewing thread.
Edited by Vodkaman, 16 April 2008 - 07:34 PM.
Posted 16 April 2008 - 08:23 PM
Thanks for all the good info diemai... Some may be helpful for my swimbait but I plan on trying my hand at a few regular crank baits so all the info will be usefull.