Band stretch

  • When you calculate the % of band stretch you want, say between 3-350% and let's say that it gives you a number of 26, does that include the wishbone length? So if my band stretch would be 26 and I use 2 inches of wishbone should I cut the bands at 24 inches for a total of 26 inch length?


    So far I have been calculating my band stretch @ 325% and cutting my rubbers at the number it gives me plus using 2 inch wishbones and I'm wondering if I'm getting the most of my setup.


    Any opinions guys?

    Relax & Go Spearfishing

  • I minus wishbone length, and the inch and a half or so that wraps through the muzzle and the half inch or so on each band where the wishbone knot is.


    But I'm not so exact on that last one OR the wishbone length. So there is always a slight variation in any new set of bands I make. I feel the difference when I change in band length by a couple inches.


    I like the "softer" feel of slightly longer bands.

  • Just think of the center of your wishbone as your anchor point...(obvious):D
    mark (on shaft) where this is when bands are taut but not stretching.=100% then measure from this mark to your desired tab/notch/fin. there's your band stretch.=BS%


    calculate % by doing maths
    StretchLength/TautLength*100=%BS
    (ex; 30in bands=appx 15inTautLength, stretched on a 120cm barrel=appx 47in
    47/15=appx. 3.13*100=313%stretch


    I think primeline has TautLength at 0% but i like to think of an unstretched band as 100%


    aaaaannnnnywhooo.....


    Try to keep it simple, short wishbone, long band stretch 300% when using >7.5mm shafts, and shorter band stretch 350% when using thicker shafts. I try not to exceed 350% unless using a roller.

    Edited once, last by Akira dkt: Math ().

  • The band gets even shorter depending on where you tie the constrictor knot. I keep things simple, wishbone as short as possible about 1.5" visible length, and the band cut to %300 elongation. I like a smooth release.


    As he said. Then, you will cut and re-tie the bands where they wear. I do it until they break in the middle... :rolleyes1:

    Marco Melis

    A bad day fishing is ALWAYS better than a good day at work.

  • How does a cheap bastard like you get so much fish ??? :D:thumbsup2::laughing:


    I bet Marco and family harvest all the fish they need by focusing on skindiving and having fun, and getting close to prey with great stalking craft. :)....just like your family Hank.:toast::toast:


    All the best, Don

    "Great mother ocean brought forth all life, it is my eternal home'' Don Berry from Blue Water Hunters.


    Spearfishing Store the freediving and spearfishing equipment specialists.

    Edited once, last by Don Paul ().

  • One good resource is the Spearitco.com Band Length Calculator. They are based on 200% rather than 300% but this will give you a constant reference point for your own bands. The thing is that so much of the band materials vary. That Band Calculator includes the Wishbones and you can set the length. I use between 340% and 360% depending on the length of gun. There is a HUGE difference in power with Multiple Band Guns as you increase the Band Stretch. I've seen some videos where 4 bands on a 5/16" at 320% is barely scratching a target at 20' but at 360% is lacing a 4" Foam target at 25'. The Smaller ID Bands are game changers. In the past we had to be very careful with tying the Standard Bands too tight because of Snappy Recoil. But I think the smaller ID Bands have substantially less volume when stretched and this means a lot of things which I'm not skilled enough to explain.. bottom line is you can tye them hotter, get better power, and not worry as much about snappy recoil.

  • I have probably only made about 25 sets of bands or so, But the inconsistency for me is the wishbone length.
    I make a double half hitch?…wrap it one more time (Riffe knot) and then tie the knot on the other end before cutting it. Then I grab the knots with two sets of needle nose pliers and pull them as tight as I can. For whatever reason, I rarely make two wishbones exactly the same length.

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