Does aluminum footing on a carbon arrow affect spine?
I'm planning on using a 2 inch piece of aluminum shaft for footing on my GT trads is this going to affect shaft spine? also can I use JB weld to glue these?
Thanks,
David
I would think JB weld would weigh much more than the aluminum
I am not expert but I understand the footing to increase the spine like it would if you cut the arrow shorter. Ive just used goat tuff glue for the footing and had no issues.
I use Gorilla Glue, and don't shoot we'll enough to tell the difference. I foot them and tune by cutting the nock end until a bare shaft puts bullet holes or is a hair weak in paper at 3 yards.
Killdeer
I use JB Weld with no problem. A friend uses Loc-Tite. I have used Super Glue and 5 minute epoxy but it did not work as well. As far as spine....I could see no difference.
The first ones I did,were after tuning.1" on the front and 1/4" on the nock end.They just about cancel each other out.Now I cut to length,foot and tune strictly by point weight.
JB Weld works fine and won't add 2 grs.Lightly sand carbon and footing interior with 220 grit sand paper,clean and glue.Let them sit overnight before shooting.
I foot my GT Trad 1535 and 3555's with a 1 inch piece of 2117. That 1 inch piece weighs 12 grains. I also sand slightly with some 200 grit sandpaper the first inch of the shaft and use Loctite epoxy to glue mine on. I can't tell any difference in a footed and non footed shaft when I'm shooting.
Good info here.
the footing will not effect the spine in anyway.
Think about how long an insert is, if you put 1" footings on your arrow it shouldn't really have a noticeable effect on the spine. I personally use two part epoxy and also add a 1/8" collar on the nock end of the arrow.
don't hesitate to foot some arrows, you really wont regret it at all.
Sand the arrow as well as the inside of the aluminum, it will help the glue stick.
Heres a thread discussing the same thing and where I saw it can increase the spine. Also on Stu millers calculator it increases the spine if the footing is longer than the insert you are using.
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=print_topic;f=1;t=105726
So 1 inch probably would not but 1.5 or more may.
is the footing to strengthen the shaft?
i have found carbon shafts amazingly stout!
not arguing, looking to learn.
thanks.
joe
the footing keeps the carbon from mushrooming out away from the insert..
(when you hit something hard it pushes the insert into the arrow)..
and i think the footing only needs to be as long as the insert, anything longer and it will affect spine.
I installed the insert into the carbon shaft, cut my footing 3" long and installed an insert in the aluminum footing. I needed the extra weight up front and the double inserts made them bullet proof.
(http://i567.photobucket.com/albums/ss115/earljeff/arrowfootingexp005.jpg)
Here is a pic of a carbon shaft I was experimenting with footing lengths, The spine of the shaft didn't change from the footing until I got close to a 12" of footing, most of the flex in a shaft is near the center. These arrows continued to shoot to the same point of inpact and flew well right out to 12" of footing. Don't know where stew gets his info from. Just letting you know how the footing worked for me.
(http://i567.photobucket.com/albums/ss115/earljeff/footedcarbonshaft004.jpg)
Great info, thanks guys!
I'm planning to foot some arrows myself. Good info here. Thanks.
Earl Jeff cant argue with the results from a spine tester, really interesting that you almost need a FOOT to see any change in spine! What I do know first hand is the 1.5 inch aluminum footing I added to a Beman MFX 500 has made the thing almost indistructable, was really happy with the results stumping!
I tend to shoot with about an inch of aluminum. My arrows have been bullet proof and I figure the shorter length will have less effect on the spine. Though it appears my worry about spine was unneeded. but they stay closer to the same point weight.
Hello Earl Jeff,
I totally agree that footing a shaft in any reasonable length does not change the static spine, I have never said otherwise. I also agree that the majority of the bending happens in the middle of the shaft when loaded statically and have done similar experiments with my spine tester.
My statements, and the equations developed for the DSC, only relate to dynamic spine. Adding an external footing effectively reduces the usable arrow length and we all know how that stiffens a dynamic spine without any change to the static spine of the shaft. What most people do not account for well in the DSC is the additional weight added up front from the footing material itself. (Basically the footed area becomes a really long point) When this weight, plus the weight of the original shaft underneath, is taken into consideration then there is very little dynamic spine change at reasonable footing lengths. Most of the time the amount of change is well withing the bows tolerance range and no significant change to arrow flight is observed. What does change is total weight and FOC% both go up.
-Stu
QuoteOriginally posted by arrow30:
[qb] the footing keeps the carbon from mushrooming out away from the insert..
(when you hit something hard it pushes the insert into the arrow)..
and i think the footing only needs to be as long as the insert.
I have found with a longer footing, that it makes a weak spot where the carbon arrow will break.
Remember there is a difference between static and dynamic spine.
I've always been interested in footing my carbons - this is an awesome thread! Thanks gang
GREAT info :thumbsup: THANKS to all :archer2:
QuoteOriginally posted by Tree Rat:
Remember there is a difference between static and dynamic spine.
What is the difference? I've heard of it, but don't know the difference between the 2.
Blue tick, i'm no expert but here's a generic version.....Static spine is measured with a weight placed at the center of a stationary arrow. Dynamic spine is how the arrow paradoxes in flight. They are related but not the same thing.
I agree with most things that were said in replies to this post I may have sounded a little rude the way I worded it that was not my intent Sorry if it sounded that way
Andrew I do agree that the footing along with a good epoxy makes the arrows very very strong. I just wanted to get the point through that I saw no difference in arrow flight or POI even with the footing extending 11 or 12" down the shaft?
My thougth were in extending the footing this far on the shaft that it would greatly aid in penetration by elimaniating a lot of arrow flex when the point (Broadhead) struck its target. Just a theory?
Can someone PM me aluminum arrow size for 55/75 GT Trads Aloha Ron
Ron 2117 will work
Great thread guys is the dynamic spine what Dr talks about with EFOC as it does some strange thimngs to spine when you get over 30% Thanks Shane
2216 works great on the 5575, at least it has been working great for me, and believe me when you hit a rock with the footing on these you won't cringe anymore...
I use 2216's for footing the GT 5575 Trad shafts.
Are you guys putting your footing flush with the end of the shaft/insert or at the actual end of the shaft behind the insert?
Jeff if the footing fits properly you should be able to slide it up against the insert without it slipping over. (behind the insert) but tight against.
QuoteOriginally posted by Earl Jeff:
Jeff if the footing fits properly you should be able to slide it up against the insert without it slipping over. (behind the insert) but tight against.
Thanks, this is what I was needing confirmation on.