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Old 12-30-2016, 01:13 AM   #1
spearq8
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Crimping stiff spectra

I have been experimenting with different ways of tying stiff spectra (benthicoceansports) line on a shaft ... obviously the stiff spectra is fantastic in that it is extremely strong and abrasion resistant ... plus it is not sloppy where it drapes over rocks and reefs and tangles everywhere. Unfortunately unlike hollow core spectra lines it cannot be spliced (at least I haven't been able to splice it) ... and doing a knot bulks up things where it actually hurts shaft velocity and changes impact point. I think I have a nice solution which is very streamlined ... and although I haven't tested it on fish ... it shoots nice in the pool and is extremely strong. I used my band tying steel hook that is bolted into concrete and pulled as hard as I could and I couldn't get the crimp to come off. That is way more pressure than a fish would put on it. I use a loop before crimping and that seems to offload a lot of the pull force of line heading out of the crimp. I actually managed to pull extremely hard without even crimping the crimp (just the bulb at the end) and was not able to pull the crimp off ... so I figure it is plenty strong to use in the field.

I also did a couple of other tests by using a double loop to make the connection even stronger for use with very thin spectra (the doubled loop line on shaft notch can be useful as that wears off with thin spectra). The idea is pretty simple but it seems to work really well and well worth a try.


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Old 12-30-2016, 01:13 PM   #2
brandon cadalzo
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Re: Crimping stiff spectra

Nice job man! I was always worried about crimping spectra until now. What diameter spectra is it? Do you notice any differences in this material vs mono as far as velocity or accuracy?


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Old 12-30-2016, 01:26 PM   #3
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Re: Crimping stiff spectra

Nice!
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Old 12-30-2016, 01:55 PM   #4
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Re: Crimping stiff spectra

That looks pretty good. I think I may rerig some of my shafts to go with a crimp. I love this line, but the knot is pretty bulky and I don't want that throwing off my accuracy. My guess would be there would be no fear of applying too much pressure while crimping as you would with mono.
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Old 12-30-2016, 11:41 PM   #5
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Re: Crimping stiff spectra

Good job Majd. I know slicing can maintain the strength of the line. Looks like that will too.
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Old 12-31-2016, 12:01 AM   #6
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Re: Crimping stiff spectra

You really need to test shock load not static , spectra has a very poor ability to withstand shock loads I've watched fish snap the spectra in a neptonics floatline ,but the pvc tube held and the fish was landed becuse the tube had "give" just like mono will stretch before it will snap absorbing shock .

If you tie 600#spectra to a solid point and tie the other end to a solid handle ,and give it a solid jerk i can break it 2 out of 3 times
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Old 12-31-2016, 03:04 AM   #7
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Re: Crimping stiff spectra

I tried 1.4mm, 1.7mm and 1.9mm Benthic spectra. That is the only sizes I have and I use the crimp that just barely allows the line to go in. I really haven't tested this to destruction so can't say how ultimate strength is. I only used a thick screwdriver and put one loop on and then put it on a hook on concrete that can handle that is rated 4 tons and pulled as hard as I could ... usually I can break or pull crimp off 300lb mono that way. Even without crimping ... just doing the loop and a good bulb ... I was not able to pull the crimp out. I managed to slide the crimp to the hook ... but couldn't pull it out. So I figure after crimpnig it is pretty strong. I actually had a few more ideas to make the hold stronger ... like maybe putting a pellet of polymorph and melting it on the back end and then crimping (makes bulb stronger) ... but seems like that is not necessary. Also had an idea of doubling the loops to reduce pressure on the bulb ... but that doesn't seem necessary. Also had the idea of using a needle to make a hole in the spectra at the back of the crimp and threading the spectra there and then bulbing ... but again that doesn't seem necessary. In the end you are only as strong as your weakest point ... in spearfishing I feel the weakest point is usually barnacles or sharp coral. 300lb mono can get cut with very little force if a line gets caught on razor sharp barnacles or corals. I know that good spectra line is used to cut out windshields off cars ... so extremely high abrasion resistance. of course this might need refinement and improvement ... but I feel this is the way to go.

I also tried longer aluminium crimps and they seem good as well.


@Phil ... the spectra from Benthic is EXTREMELY strong ... there is no way on earth that a human can break the 1.9mm spectra line. That stuff is strong!




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Old 12-31-2016, 09:26 AM   #8
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Re: Crimping stiff spectra

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Originally Posted by spearq8 View Post
I tried 1.4mm, 1.7mm and 1.9mm Benthic spectra. That is the only sizes I have and I use the crimp that just barely allows the line to go in. I really haven't tested this to destruction so can't say how ultimate strength is. I only used a thick screwdriver and put one loop on and then put it on a hook on concrete that can handle that is rated 4 tons and pulled as hard as I could ... usually I can break or pull crimp off 300lb mono that way. Even without crimping ... just doing the loop and a good bulb ... I was not able to pull the crimp out. I managed to slide the crimp to the hook ... but couldn't pull it out. So I figure after crimpnig it is pretty strong. I actually had a few more ideas to make the hold stronger ... like maybe putting a pellet of polymorph and melting it on the back end and then crimping (makes bulb stronger) ... but seems like that is not necessary. Also had an idea of doubling the loops to reduce pressure on the bulb ... but that doesn't seem necessary. Also had the idea of using a needle to make a hole in the spectra at the back of the crimp and threading the spectra there and then bulbing ... but again that doesn't seem necessary. In the end you are only as strong as your weakest point ... in spearfishing I feel the weakest point is usually barnacles or sharp coral. 300lb mono can get cut with very little force if a line gets caught on razor sharp barnacles or corals. I know that good spectra line is used to cut out windshields off cars ... so extremely high abrasion resistance. of course this might need refinement and improvement ... but I feel this is the way to go.

I also tried longer aluminium crimps and they seem good as well.


@Phil ... the spectra from Benthic is EXTREMELY strong ... there is no way on earth that a human can break the 1.9mm spectra line. That stuff is strong!




Yes straight pull spectra is extremely strong ,but add a dynamic load and it fails , this is why it can be used for winch lines and dock lines , but not for tow lines or anchor lines . A 200# nylon line will out proform a 1000#spectra line in a dynamic test ,use the same lines in a static test and spectra will be stronger

Spectra has no stretch and so no ability to absorb shock this let's a moving load exert far more Kn energey on it ,
M x V2
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Old 12-31-2016, 09:44 AM   #9
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Re: Crimping stiff spectra

Looks great Majd, i'm gonna give this a go on my next Wahoo/AJ trip. It'd be interesting to see in a pool test how much the bulkier knot affects accuracy.
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Old 12-31-2016, 10:21 AM   #10
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Re: Crimping stiff spectra

I plan to do a full comprehensive test of different shooting lines and cable and see how it affects accuracy and penetration. Also to test ultimate breaking point of line and cable. There probably is a better way of crimping ... but the only way to really find out is to make a jig and pull the line till it breaks. I have a gauge that goes to 2 ton ... also the pulley to 5 ton ... I just need to put it together and find the time to test it all. I want to really test 1.2mm coated cable as well as it looks very strong and with a coating it looks like it might be not too difficult to cut as a knife will dig into the nylon coating and allow some leverage.

@Phil ... well I did do the sharp jerking ... just as my wife was walking in the room ... got a really strange look ... she said it looked like I was trying to hurt myself. You must have gorilla arms as I am nowhere near breaking that stuff ... not even the 1.4mm stuff. I think not all spectra is the same ... this stuff is wicked strong and very densely woven.

Last edited by spearq8; 12-31-2016 at 10:33 AM.
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Old 01-03-2017, 01:00 PM   #11
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Re: Crimping stiff spectra

Even if spectra has a poor ability to withstand shock, wouldn't bungies help? If my shooting line is rigged to my gun I have a muzzle bungee, with a reel it is shooting line>muzzle bungee>reel line, and breakaway shooting line>bungee. It isn't like the line is being yanked from a deadlock. There should still be some give by other means.
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Old 01-03-2017, 11:09 PM   #12
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Re: Crimping stiff spectra

What crimper are you using/?
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Old 01-04-2017, 12:26 AM   #13
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Re: Crimping stiff spectra

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Originally Posted by FreediveCA View Post
Even if spectra has a poor ability to withstand shock, wouldn't bungies help? If my shooting line is rigged to my gun I have a muzzle bungee, with a reel it is shooting line>muzzle bungee>reel line, and breakaway shooting line>bungee. It isn't like the line is being yanked from a deadlock. There should still be some give by other means.
The point is you have to go in knowing the positives and the negatives and be prepared for the problems . Fish can and do change direction get some slack then hit the end of the line at full speed , a hundred pound fish can generate well over a thousand pounds of knetic energy( M x V2 ) if you are using spectra you have to ether have a bungie or be using a reel where more line can be pulled out . A nuzzle bungie isn't desged to obsorb shock it is really just for holding tension on the line when the gun is loaded
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Old 01-04-2017, 12:20 PM   #14
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Re: Crimping stiff spectra

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The point is you have to go in knowing the positives and the negatives and be prepared for the problems . Fish can and do change direction get some slack then hit the end of the line at full speed , a hundred pound fish can generate well over a thousand pounds of knetic energy( M x V2 ) if you are using spectra you have to ether have a bungie or be using a reel where more line can be pulled out . A nuzzle bungie isn't desged to obsorb shock it is really just for holding tension on the line when the gun is loaded
I follow you. Thanks for that bit of information. Something to consider.
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Old 01-04-2017, 01:41 PM   #15
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Re: Crimping stiff spectra

Phil is right, in fact it is the jerk that busts things, or a change in acceleration which is rapid. A long bungee section irons out the jerk by dissipating the energy. If you want to test a line tie then attach the line to a very heavy object and drop it and see what happens when the line halts the descent of the object.
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