spectra loop packs

[doyenofcastle]

hi guys,

what s the recommended line dia. , strenght to make the spectra loop packs ?I made one using 97kg /1.5 mm rope but I think it will be cut cause the pulling strenght of rubber is 250--300 Ib

 

[Mr. X]

Hi Doyen, can you please clarify. Specifically: What do mean by "spectra loop packs"? Are you talking about making dyneema/UHMWPE wishbones? Or perhaps constrictor cord or perhaps toggle loops to be inserted into the rubbers (usually with a big knot or plastic/metal toggle)?

If the former, what type of spear are you using? e.g. does it have hard notches, smoothed notches, shark fins or pins sticking up, for the wishbone to engage with?

 

[doyenofcastle]

toggle loops what I was using is 1.5 mm with strenght 79 kg ,I have tried to tie them by the tying twine from speardiver but they pull out easily and the tie rope was relaxed and not catch !!

 

[Mr. X]

What cord are you using for you constrictor cord? I find that braid has the right sort of thickness but it stretches - so it is vital that it is done up very tight. spearitco.com sell kevlar for this - presumably because it does not stretch, however, it seems a bit thin & therefore more likely to cut into the rubber.

What are you using as the toggle - just a knot or a bead of some kind?

 

[doyenofcastle]

toggle loop is using 2 mm dyneema with single knot or 1.5 with double knots

 

[Mr. X]

Suggest you take a look at this website spearitco.com , as they offer various cords & toggles for this sort of thing.
e.g.

Spearit Original Kevlar®² Speargun Band Constrictor Cord 1mm(200lb)

NTR Speargun Band Wishbone Beads


Spearit Kevlar®² Speargun Line 1.7mm

Spearit Spectra®¹ Wishbone Kit with NTR Inserts (Sz Med)
Only $9.99 per kit

_Recommended for blue water where structure is not an issue_
_As low as $0.12 per foot_ _Everything you need to make and install 3 wishbones for 1/2in-5/8in bands_


Looks like the above plastic toggles provide an alternative approach, replacing both the toggle/stopper knot and the loop - allowing the shorter wishbone cord to be replace without messing about with the rubbers & constrictor knots

I re-use the nylon toggles from my Rob Allen dyneema wishbones but also have some heavy, oval/egg-shaped beads from the above company, which I have yet to use. Toggles seem like a more secure approach than just using stopper knots to me.

BTW Which knot do you use? I would probably use a double overhand knot (which is also what I used as the stopper knot behind my toggles).

.

 

[doyenofcastle]

very good , due you use any other type of knots instead of constrictor to keep the wishbone ?

 

[Mr. X]

very good , due you use any other type of knots instead of constrictor to keep the wishbone ?

No, only the constrictor knot. I suppose there must be other knots which will easily slide tighter but not slip looser but I haven't come across any. The constrictor knot is relatively simple and works remarkably well.