LINGHUNT Rubber Tubing

Rubber Tubing is the #1 Energy Storage method of choice for SPEAR-Os.

There is lots of good information on the various dive forums. Be sure to visit and research them for more details.

% Stretch Scales

The Percent Rubber Scale across the web uses two different scales. This tends to get folks mixed up on what they are buying and reading about.

My best analogy for this: You are standing and decide to take a few steps and want to count the number of steps. You take the first step and count "ONE" and "TWO" . . . . .

But some do this and count "ZERO" then "ONE". . . . .

Sounds crazy but this is what is happening with SOME rubber percentage references.

I use the non shifted scale where 0% = 0 force stored in the rubber. [ Illustrated in Yellow below ]

Measurements for Sizing Rubbers

I made a graphical guide to sizing rubbers. I used a 200% example , on the ZERO STEP scale this would be 300%. If you wanted a true 300% you would have 4X for for distance from Wishbone to Grip position.

Rubber Loops

There are a few different ways to modify a rubber with loops. The is commonly called the Manny Puig knot. The Loop is also used for a float line attachment. The loop contains the float line rope or clip to the area of the loop.

Linghunt Power / Length loop. -- I never really liked the big rubber knot for a loop, but idea is clever and simple.

Verus the knot, I came up with using high load rated wire tie and a small piece of tubing to give a loop that was a smoother fit to the hand.

A simple constricter knot with larger cordage also works, even with a rubber length. The short rubber length makes this tough to do, but possible with a little effort.

Loop placement power Different POWER Levels.

Loop placement power Different POLE SPEAR Lengths

Float line attachment to Rubber:

I like to use a Prusik knot

Set the non slip knot to the side rubber so it doesn't effect the shot. This will also change the shock absorber effect of the float line to the pole. Only one side of the rubber will be in tension with fish pulling for small fish load, both sides are used with larger forces.

The Klemheist is another clever knot. This one ONLY grabs in one direction like a check valve or diode.

The Prusik or Klemheist will both work, The Klemheist is probably better choice.

Rubber Graphs ( Force vs % stretch)

Typical Polespear Rubber: There are other sizes on the market too.

------------------------------------------------------------------------

Typical Speargun Rubber: There are other sizes on the market too.

Properties and Methods to Consider:

STORAGE: When your rubbers are not in use, clean and wash them and store them in the back of your refrigerator. This will add to the life of the rubber.

UV Light: Not good for your rubbers, when practical don't leave the rubbers out in the sun to bake.

Metal vs Elastomer ( Rubber ): Check out the stress/strain curve comparision of metal vs an elastomer. Note the long linear region on the Elastomer curve and how it matches the graphs above.

ENERGY LOSSES: This is a general graph on rubber expanded and contracted. You should notice the amount of energy or Force in the rubber is less when it contracts. These losses also have a time factor. Many factors involved, beyond the scope of where I wanted to go here.

One of the components is the temperature change of the rubber. Stretch a rubber band back and forth and feel the tempersture rise. You can place it on your cheek. The heat energy had to come from somewhere.

Mori Raw Data on Rubber ( Note the numbers on losses with 1 hour time )

[ I don't have access to test procedures and measurement methods ]

Rubber Specifications and Manufacturers

Primeline and Kent are two of the manufacturers out there. There are others as well.

Go to each web sites for currect specifications and details.