how much weight for Carbon

[flungonin]

First time using Carbon for longbow. Always used wood. So, I have a #61 Crusader. 28" draw, using Easton Raider 400 8.4 gpi, 30.5 inch, 125 field tip, 3 4inch vanes, 4 1/2" foc. Am I correct in thinking I need 600+gr. Reading another post on here   :confused:  I am going to need 2 weed eater lengths of line and maybe an additional 50 gr.

[Flying Dutchman]

It is my finding that longbows like 10 gpp. So at 61# you should be around 610 grains for the total arrow weight.
When calculating with the numbers you gave us for your arrow set-up, your arrow weights should be around the 425, right? That would result in a gpp of 7, which is dangerously low....

There are several ways to go up in weight. A common way for hunters is to take a stiffer spine and add more frontweight. There are many frontweight adapters in different weights. And there are different broadheads in different weights... Increasing frontweight means you will increase your FOC, resulting in a higher impact. Which is great for hunting. Increasing frontweight also means your dynamic spine value will get significant lower.
You will have to bareshaft to find out what combination works for you.

Another way to get more gpp's is inserting something in your shaft, like weed-eater line, aquarium tubing and so on. This will keep your FOC low, and won't chance your dynamic spine value.
I use weed-eater line myself. It comes in different diameters with different weights. The type I use has a 2.4 mm diameter and weighs typically 55 grains at 30 inches. When installing, put the line in as far as it will go with a little pressure. Let stick one inch out and cut it there. Push the nock over the weed-eater line and push it in the shaft. In this way the line will be locked up and won't rattle in your shaft. You can put two or more lines in your shaft to get the desired weight.

And of course you could combine weed-eater line with a higher frontweight to get the desired weight.

You just will have to play with it and will have to bareshaft to see what works for you.

Hope this helps bro!

PS:

I've been in the same boat as you. In the end I succeeded in developing carbons with the same characteristics as my woodies. Both give me 9.5 gpp and a FOC of 10%. This allows me to switch between carbon and wood without any difficulties. But it took some time to get there...

[Steven E Milbocker]

I've found heavy points do little as far as affecting spine on carbon arrows.They are much more affected by shaft length. So I'd say load the point with heavier broadheads and brass inserts.

[Flying Dutchman]

When you bareshaft you can see clearly the difference between 20 grains already....

[damascusdave]

This is common issue that is most easily solved by going to aluminum arrows rather than carbon...there are carbon arrows that offer heavier gpi such as the Heavy Hunter but they are kind of pricey...you can make the weight you want easily with Easton Legend aluminum which are reasonably priced...plus aluminum is far more receptive to changes in point weight to modify dynamic spine...or you can keep playing around with carbon until you frustrate the heck out of yourself...you choice

DDave

[frassettor]

I shoot the same specs with my longbows as you do, I use CX350 31" BOP 100 brass insert, 300 tip. Finished weight 785
They fly wonderful

[flungonin]

OK, thanks fellas for all the info. Today I went and got weed-eater 2.4mm line. Stuffed 4 strands down the shaft. So I should be safe shooting tomorrow. So according to
calculations:
arrow length 30.5
GPP         x 8.4
     total    256
field tip   + 125gr
     total    381
weed-eater     55x4=220  55gr per 30 inch
        total 220
            + 381
              601
Does this come out correct. I am not quite at a solid 10GPP,

[Flying Dutchman]

As for weight, you forgot your fletching, nock and insert. You can add at 35 grains for that     Most important is you are around the 10 gpp.

Did you actually weigh the weed eater line? Different brands means different weights.....

 I wonder if your FOC did not became too low. Here is how to to estimate that: find the balance point of your arrow. Mark it. Measure the distance from the marked balance point from back of point. Let's say that is 12 inch i.e. Divide your arrow length (back of point to valley of nock) by two. In your case that is 15.25.
Substract the distance balance point from it, in this example  15.25 - 12 makes 3.25.
Divide it by full arrow length times 100 to find your FOC in %, in this example: 3.25/30.5 x 100 = 10,65%.

As for FOC value, I would not get lower then 9%. Lower then 9% will make your arrow unstable. Everything above it is good. The more FOC, the more penetration, but the more your arrow will dive at bigger distances. Personally, I like a FOC of 10%.

Then you have to find out how your arrow flies wit the 4 lines and if it doesn't rattle.

My guess is you will be fine...            

BTW: do you have a digital grain scale? This comes in very handy for stuff like this. They cost only $20,- at 3 Rivers Archery.... And then you really know how much your arrow weighs....

[Bonebuster]

Getting a grain scale is GREAT advice...you will use it all the time.

Also, adding weight to a carbon arrow is easy with any number of options listed or thru the use of weight tubes.

With just a bit of a learning curve, you will end up with the best flying, and most durable arrow you have ever used.

With a little experience, you will be able to put together a carbon arrow that weighs what you want and shoots GREAT out of any particular bow you have.

Actual draw weight, lenght, and centershot specs are all you need.

A few things to remember. Carbons act stiff and cutting them affects spine greatly...cut in small increments.

I think the biggest mistake being made with carbons is the use of a shaft that is too stiff.

Get it right, and you will SEE and FEEL that you have it right alot like with well matched wood arrows.

[randy grider]

Add all the weight you need to the front of the shaft, if it weakens it too much, go to a heavier spine. Getting carbons to fly good is not the rocket science  some try to make it out to be. Shaft length, and point weight have drastic affects on spine. Don't believe the above statement about point weight having little affect, just not true at all.

[Flying Dutchman]

So let us know how you did Steve!

[Legolas]

Got a new bow for this season- A Wind Warrior from White Wolf.
I got some Byron Ferguson heavies AND loaded them with 3/16 inch nylon string to 750 grains!!!
I will shoot under 20 yds and using some 170 gr Badger Broadheads.
This set up is absolutely overkill for whitetails but I am serious about double lung penetration.
Let you all know how this works out.