Speargun Band Assembly
Replacement bands for certain types of band-operated spearguns may not be readily available from your local dive shop. Some band-gun users may want to experiment with different band lengths and diameters in an effort to improve performance. In any case, assembling speargun bands isn't particularly difficult to do. Making "custom" spear gun bands requires only the rubber tubing, wishbones with rings, a couple sets of pliars, a vise, a nail and a grinder. Making your own speargun bands can be a minor challenge the first time or two but with the tools listed here and a little practice, it will become much easier.
If you intend to use bands that are heavier or shorter than your gun was designed for, the increased band tension could result in trigger loads that are greater than the gun can safely withstand. Increasing the trigger load WILL GREATLY increase the risk of misfire. You must exercise extreme caution if you increase the trigger loading on your speargun. BASIC GUN SAFETY REQUIRES THAT ONE MUST NEVER POINT A SPEARGUN IN THE DIRECTION OF PEOPLE OR THINGS THAT COULD SUFFER MORTAL INJURY OR DAMAGE IF THE GUN WERE TO FIRE UNINTENTIONALLY.
Custom made bands will take about 2 hours ro complete and will be better than a band that you can buy from the store.
Tools & Parts Required
1. Rubber tubing cut 2" longer than the intended finished length of the band. The diameter and length should match the bands that were originally made for your speargun.
2. Wishbone with brass slugs and retainer rings (aka: collars.) that are properly sized for the tubing.
3. A nail that fits snugly inside the rubber tubing & with a head that is approximately 3/16" in diameter.
4. Table-mounted vice.
5. A grinder.
6. Vice-Grip pliers.
7. Needle nose pliers.
8. Denatured alcohol (may be used to lubricate wishbone slug for insertion into tubing.)
1. Insert the nail into the end of the tubing. The head of the nail will be a guide for grinding the taper in the end of the rubber tubing. (You will remove this nail after the end of the tubing is ground.)
2. Grind a taper at both ends of the tubing. The taper should be about ¾" long.
3. Slide a retainer ring over the wishbone and then push the brass slug into the rubber tubing until the tapered end reaches almost to the bend in the wishbone. The slug must fit tightly inside the tubing.
4. Clamp the tubing tightly in a vise at a spot a couple of inches beyond the brass slug.
5. Push the retainer ring as far as it will go over the tapered point of the tubing and then clamp the Vice Grip pliars against the retainer ring taking as much of a bite as you can get on the tapered end of the rubber tubing .
6. Pull the vice grips away from the vice, stretching the rubber tubing. This stretching will cause the diameter of the tubing to be reduced so that the retainer ring may be pushed further up over the tapered end of the tubing. As you start to pull on the tapered end, slip the needle nose pliars between the retainer ring and the Vice Grips so that you can slide the ring up the taper as the rubber is stretched. Once you have moved the retainer ring further up on the taper, release the Vice Grips and then reset them gaining a better "bite" on the rubber.
7. The retainer ring must be slid up the tapered end until it is over the full diameter of the tubing and at least ¼"past the section of the tubing that was ground to a taper..
8. Now for the hard part; repeat the procedure on the other end of the tubing and the opposite end of the wishbone & slug. Stretching the tubing to slide the retainer ring over the first end on the wishbone is easier because when you are working on the second end, you will be pulling against the tension of a loop of tubing rather than only pulling against the tension of one end.