Basic Speargun/Polespear Band Assembly
1. Cutting the rubber to length: The first step in assembling a speargun or polespear band is cutting the rubber to the proper length.
The first step to determining the proper length is deciding how you are going to finish the band ends. Most spearos take the practical approach and simply square cut the ends of the rubber. We could tell you that tapering and putting a pretty finish on the band ends, like the gorgeous bands we sell for instance, is going to make a significant difference because of lowered hydrodynamic drag, but that would be a stretch. The difference, if any, is imperceptible. So to keep it simple, we will stick with square cutting the ends for this tutorial.
The most accurate way to match the power of your old bands is to keep the same distance between constriction points. So start by measuring your old band. If you have a cord wishbone, cut it ,so you can lay the band out straight and get an accurate measurement from constrictor knot to constrictor knot ,or if it has rings, from the outside of one ring to the outside of the other ring.
To arrive at the overall length of the rubber, you will need to add, AT A MINIMUM, the diameter of the rubber you are using. Example: If the old band is exactly 20 inches in length, measured constrictor to constrictor, and your using 5/8 inch rubber, then you will need to cut the rubber for your new band to at least 20 5/8 inches in length.
Helpful Hint: If you are using our NTR Beads or Inserts, they are designed so that when fully inserted, the constrictor should be positioned 3/8 inch from the end of the rubber. We recommend fully inserting them and adding 3/4 inch for all rubber diameters. If you insist on saving every 16th of rubber possible, notice the raised ring in the middle of the bead shaft, this is the minimum insertion point for 1/2 inch rubber.
So now, measure it, mark it, and cut it.
Helpful Hint: A pair of sharp anvil pruners does a nice job.
2. Mark the location of the constriction points: Now, mark the band where your constrictor knots will go. If you went with the minimum length, then measure in from each end 1/2 the diameter of the rubber tubing and place a small mark. In any case, NEVER tie your constrictor knot less than 1/2 the diameter of the rubber, from the end. Tying it closer can result in the wishbone pulling out regardless of how good your constrictor knot is.
Helpful Hint: A silver Sharpie is the best way we've found to mark black rubber.
3. Insert the wishbone: None of our stock wishbones require special tools or even needle nose pliers to insert so we won't get into that frustrating and possibly painful process. If your using one our V wishbones, simply lube it up with some hand soap or silicon lubricant and shove it in. The terminal should be pushed in at least beyond the constriction point. For our NTR Beads and inserts lubricate and push them in as far as possible with your thumb.
Helpful Hint: Getting a little lubricant inside the tubing prior to insertion is much more effective than lubricating the wishbone alone. A pipe cleaner dipped in lubricant is a good applicator for this purpose.
4. Tie your constrictor knots: We have another page in this section completely devoted to the "How to...." of the single and the double constrictor knot, so we won't get into the details here. Position and tie your constrictor or double constrictor directly over the positions on the rubber that you marked earlier.