Bands;how long?

I am making new bands with 9/16" rubber. It is about 28" from the slot at the tip of my gun to the center slot on my spear shaft. Is there a (Rule of Thumb) for the proper length to make the bands or is it just all you can pull. Also, whats a good way to make a constrictor behind the bead on the wishbone ? Thanks for any help !

MAKO Spearguns - Instructional Info The link is for the constrictor knot.
Band length is probably listed on your manufacturers website. Or post your gun make and model here. And also how many bands you are planing to put on. Some guns can't handle rules of thumb.

http://www.makospearguns.com/instructional_info_ibc.php This link is to the band chart for mako. But refer to your manufacturer.

If you are making the band, just run it through the muzzle before cutting it and then pull it back without the wishbone inserted. This should give you a good idea of the amount of tension you want to have and will help you to determine how long of a piece of latex tubing you should cut off.

I think the rule of thumb is that you want the rubber to approximately triple in length when stretched. I think you can go to 350% if you really want to.

Also, it is probably better to cut it a little longer and then decide that you want to cut off an extra inch and re-tie the wishbone rather than to cut it too short on the first try and make a band that won't work for you.

9/16" bands are pretty weak, so unless you make it way too short, you should be able to load pretty easily.

3-3.5 to 1 so at 28/3 you have 9" per side or an 18" band roughly.

I use 22 to 24" 3/4 diameter for a 42" pull.

Actually I ordered 5/8" rubber not 9/16" like I posted. My gun is an old Scuba Pro gun that I bought new in 1978 out in Oceanside, Ca. All I will most likely use it for is Calico bass in the kelp and maybe smaller Stripers in some the lakes here in AZ. Thanks for the help!

This is probably a bit late to post, but from the first notch or fin on your shaft to the muzzle or wherever your band slot is, measure and multiply X .66 will give you your "active" rubber. Then and add about 3/4 of an inch on each end or 1 1/2 inches total to allow for insertion of your bead or wishbone. The constrictor knot is fairly simple after you do it several times. There are a few good you tube videos that explain it very well. That will get you started, bt you can shorten or lengthen the band to whatever you feel necessary. I wouldnt make em too short though, could be hard to load ~