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How much does painting and topcoating add to weight?
9 replies to this topic
Posted 27 September 2009 - 03:47 PM
I currently try to weight my lures before putting finishes on them. I assume this is what most people do also, for a variety of reasons.
When I'm weighting a lure, should I bother taking the weight of paint and epoxy topcoat into account in any serious regard?
Posted 27 September 2009 - 05:49 PM
yes it can add quite a bit but depends on how this the finish is. Generally the thicker the finish the less action of the lure.
Posted 27 September 2009 - 06:47 PM
it depends upon lure size. i have painted a few over the years.we used to order pradco nu. 9 -a bombers. they came in pearl wh, or chrome. with painting over thousands they all caught fish. now on a ultra-light bait it may, slightly become an issue... more likely not though.
Posted 28 September 2009 - 01:20 AM
Paint and a Devcon epoxy finish usually adds about .03 oz to the weight of a 2 1/4" bass bait. It's mostly about the topcoat, so using a different coating will change that. It may or may not be significant but it's worth considering. Don't forget the weight of the hooks either.
Posted 28 September 2009 - 01:34 AM
If I balance f.e. a slow sinking or even suspending glider jerkbait , I need to have it's back still slightly sticking out in the testing water bucket(with hooks and leader attached) , when at first taping on the weights to find out about their size and location .
When finally embedding them into the lure , the drilled out material , glue and and also paint and topcoats will render the lure heavier in the end , so this way I could achieve my aim , though it is always hard to predict , also depends on the density of wood used .
Far easier to achieve a fast sink bait .
greetz , diemai:yay:
Posted 28 September 2009 - 05:07 AM
"Vodkaman" (Dave) had a formula, or theory, or something for this, so maybe do a search of his posts - I think you will find it is all more or less neutral, even D2T is pretty neutral.pete
Posted 28 September 2009 - 05:29 AM
When you have to cover up as many mistakes as I do it probably adds a pound or two.
Posted 28 September 2009 - 05:51 AM
Never got around to finishing the project Pete. Will return to it one day.
for a series of identical bodies (size and shape), the final weight will be constant, if you are going for neutral buoyancy, regardless of the wood density.
So if you know the weight of the drilled blank, filler, all the hardware, AND the paint, then you can work out the ballast required. This will get you close, but a little fine tuning may still be required of course.
On the first lure, weigh before and after the paint process. This will give you a good guide, but will require consistent applications for accuracy.
Epoxy top coats have a specific gravity of around 1.2, so if your top coat weighs 1 gram, it does not mean you have to reduce your ballast by 1 gram. The actual adjustment to the ballast would only be 0.17 grams.
The accuracy required to achieve neutral buoyancy is about 1/200th of the weight of the finished lure (from experience). So if the lure weighs 20 grams, then you need to control this weight to within 0.1 grams or 0.0036 ounces. This level of accuracy only really applies to neutral buoyancy, which was not the topic of this thread.
Another way to think of it is: you have added a gram of weight in epoxy to the lure, but you have also increased the volume of the lure by the thickness of the epoxy. This means that the lure can support more weight, something to do with archimedes. If you use metric units, the weight of the lure in grams is equal to the volume in cm3 for neutral buoyancy.
Posted 30 September 2009 - 01:26 PM
Thanks guys Vodkaman, great writeup I was actually just looking around for the density of epoxy just now and checked back on this thread!