Can you add weight to an arrow without affecting spine?

[sam barrett]

Is it possible to add weight to an arrow without affecting spine?  I've heard of putting weedeater line in the shaft to add weight, will something like that affect spine too?  Thanks!

[McDave]

Some arrows, such as Gold Tips, allow you to add weight to both the front and rear.  Adding weight to the front decreases spine, while adding weight to the rear increases spine.  However, it's not an even tradeoff. Adding weight to the back increases spine more than an equivalent amount of weight added to the front decreases spine.  So you have to play with it if you want to keep the same spine.  As I recall, adding 2/3 to the front and 1/3 to the back keeps the spine about the same, but this may vary.  Adding something that increases the overall weight of the arrow from front to back, like weed eater line, might increase the overall spine, so you might have to increase your point weight some to compensate, which isn't a bad thing.

[Matty]

Last yr I was shooting 1535 GTs they were flying incredibly but their weight was under 500 which I think is too light for elk. Someone posted something about putting nylon string into the shafts. It took some work but it gave them significant weight and didn't affect the arrow flight one bit. And it made the arrow much more quiet. IMO weight tubes and weedeater line make the arrow rattle.

[Paul_R]

Assuming you're talking about carbons, sure. Just use weight tubes.

   Weight Tubes

[fnshtr]

Originally posted by Paul_R:
Assuming you're talking about carbons, sure. Just use weight tubes.

   Weight Tubes  

X2

The weight tubes did nothing noticable to my GOld Tips as far as spine is concerned.

[sam barrett]

Awesome!  Thanks guys.

[Stump73]

Acrylic 3/16 inch rope will add weight with out spine. My last year hunting setup went from 448gr to 592gr with 30" inches of rope in my 25 7/8" shafts. Shot great and hit hard.

[FerretWYO]

As long as you add weight to the whole length of the arrow the effect will be minimal if any

[old_goat2]

Adding any weight effects dynamic spine to an extent because it slows the arrow down but I don't think it's significant. But what adding weight to the whole length of the arrow will change significantly is the FOC. If you don't believe me put some numbers in an FOC calculator. I did the paracord thing on an arrow that I'll admit didn't have a lot of FOC to begin with. Maybe 12-14%, plugged the numbers into my archery software after adding the cord and the FOC shifted to .1% yes that is a point in front of the one. The arrows flew really squirrelly, very unforgiving! It adds to the arrows GPI but nothing to the tip weight so FOC has to go down!
My suggestion if it's possible with your setup is to add tip weight and build out your strike plate to compensate for your now weaker arrow. That's what I ended up doing with the arrow i mentioned. Good luck, it's sure fun stuff to experiment with!

[rraming]

Adding weight tubes makes the shaft act weaker - I have tested this, you could take maybe 25 grains off the front as well after tubes are installed.

[2bird]

As said before weight tubes, 3 rivers sells them 12 for $12.75

[JimB]

I've played with this a lot,using weight tubes,aquarium tubing,all types of nylon and poly chords and powdered compounds like borax.

Starting with a well tuned arrow,they all made the arrows quite a bit stiffer and murder to retune.You may use a flexible,full length inner weight but spine is still changed,drastically.

This is why:
1.Adding weight to the rear of the shaft stiffens dynamic spine.
2.All of our arrows have a balance point somewhere forward of center.
3.This means the rear of the arrow,behind the balance point, is longer(longer steering arm)and x amount of weight in the rear has more effect than the exact same amount of weight applied to the front.
4.When we install a full length weight tube,there is a disproportionate amount of weight behind the balance point.It depends on the original balance point but the weight tube puts maybe 2/3 of the weight behind the balance point and 1/3 forward of it.That's exactly the opposite of how it needs to be IF you are staring with a well tuned arrow and want it to stay tuned.
5.If that arrow,was truly tuned to start,and you change that balance point,you changed tune.All full length weights change the balance point quite a bit.

You can test this very quickly without permanently altering your arrow.Find something to balance your arrow on and clearly mark that balance point.Now stick some weight to the front,like split shot and tape,chewing gum-anything.Watch how the balance point shifts.Move the same weight to the rear and see how far the balance point shifts,as opposed to when it was upfront.It will have moved farther.

Again,I'm only talking about an already tuned arrow,then adding overall weight.What I've learned from a lot of testing,if my arrow WAS tuned and I shifted that balance point(same shaft length),it was no longer in tune.

What I did finally discover was that I could increase the overall arrow weight as much as I wanted,by adding some of the weight to the front and a smaller portion of it to the rear.It can't be equal.Say I wanted 100 grs more overall arrow weight.Something like 65 grs or more would have to go up front and the remaining 35 or less goes to the rear.That percentage depends on what proportion of the shaft is behind the balance point and how much is forward.

I found that I could quickly test how much I needed front and back by adding the stick on weights till my balance point.Then it was a matter of figuring how to build that much weight in the front and rear of the arrow.

Now,if you want to add a weight tube before tuning and tune from their,you can but be prepared to have to add more up front weight than you imagined,and there will be no way to predict the final arrow weight.It will be what it will be.

I found that adding the weight front and back,I could make the arrow exactly the finished weight I wanted.Sorry for the long post but I blew a lot of time figuring this out and maybe someone can use something there.It seemed complicated getting there but once I figured out the formula,it is very simple now.

From what I've seen,if I have a well tuned arrow to start,changing it's balance point,changes tune.It's that simple.

[2bird]

JimB, So I currently shoot a 405 grain arrow out of a 45# recurve, but I would like 475-500 grains for hunting, how would you effectively increase the overall arrow weight with minimal retuning? is it even possible?

Don’t mean to hijack the thread Sam, thought you would benefit from this question also.

[JimB]

2bird,it is easiest with carbons or possibly aluminum.Here is what I've found works for me.Find and mark your balance point.Easiest for me is to take a wad of tungsten putty,the actual weight I want to add to my overall arrow weight.Experiment with adding putty front and back(just stuck on the outside,temporarily) till you get the combination,front and back that keeps your original balance point.Weigh the putty and find out how much weight you need up front and in the rear and build accordingly.

You can glue lead or small,brass rod in your nock.On the front end you can use steel adapters,brass inserts etc.You can add lead shot inside the cavity of a 100 gr steel insert and also ahead of the adapter, inside the front of the broadhead's ferrule.With tubular shafts and glue on heads,there are a lot of creative ways to fine tune weight.

[2bird]

Ok thanks

[John3]

I've done this for years.. Add appx 100 grains to my arrows using 3/16 poly rope.. Melt both ends so they will not fray and use any wire (liberated coat hanger) to install..  Does not effect spine.