Alliance #107 Rubber Band Tests

136949 Views 327 Replies 95 Participants Last post by wll, 5 mo ago

Henry the Hermit

Discussion Starter · Aug 13, 2011 (Edited by Moderator)

One of my favorite flat bands are ordinary Alliance #107 rubber bands, available from most office supply stores in the US, though I buy mine from Amazon.com. They are cheap, require no tricky cutting and last a long time. Are they good enough for you? Good question, so I decided to do some tests to help you decide.

For comparison, I used two identical frames, my own design La Cholita in half inch plywood. One frame was banded with #107s and the other with .050 food grade latex from RubberSheetRoll.com cut the same width as the #107s. Both bandsets were fitted with Performance Catapult's (Jim Harris) pouches. I tied them on with thin strips of TB Gold in an OTT configuration and 8 inches between the pouch-tie point and the frame.

The first step was to fire 25 break-in rounds with each slingshot. I used .375 (9.4 mm) lead balls, and got a bit of hand-slap with both, indicating there is more energy available. Then I measured my draw-length at 34 inches, and using a digital fish scale measured the pull strength at 14.08 pounds for the #107s and 11.44 pounds for the latex.

Next I set up my speed test equipment, consisting of a metal chair with a wooden stick affixed to the back and a clothespin to hold a 5x8 inch index card located exactly 10 feet away from my catch box fabric. Then I placed my Acer Netbook on the chair and using Audacity, I recorded the sounds of a dozen or so shots from each slingshot hitting first the 5x8 card and then the cloth backstop 10 feet away. Then I transferred the files to my big computer and read the files to measure the elapsed time between the two strikes. I entered that information into a spreadsheet and calculated the speed in fps for each shot and finally got an average speed and energy. Here are the results.

#107
Average for 10 shots = 173.87 fps, 5.03 lbs/ft energy

.050 latex
Average for 10 shots = 183.95 fps, 5.60 lbs/ft energy

So far, no surprises. I expected the latex to be faster, but was pleasantly surprised to find the #107s to be as fast as they are.

Next, I will shoot both slingshots until the bandsets wear out or break. Past experience tells me to expect about 300 shots from the latex and more from the #107s. Every shot is recorded, so for the first time I will have an accurate count. ~~Whichever breaks first will be replaced with a set of Tex's Field bands, and I will do the same speed, energy, and longevity tests on them, for comparison purposes.~~ Note: Everyone already knows that Tex's bands are as good as it gets, so there really is no need for me to reinvent the wheel.

Henry

14 August, 2011 - The left side latex band broke at the pouch after 390 shots.
15 August, 2011 - 490 shots total on #107 bands. Very light scuffing at fork. No tears.
16 August, 2011 - 600 shots total on #107 bands. No tears.
17 August, 2011 - Velocity test - 178.7 fps 5.3 lb/ft energy
19 August, 2011 - Band broke at 696 shots

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Charles

· #10 · Aug 13, 2011

Very, very useful stuff ... keep up the good work!

Cheers ...... Charles

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Charles

· #85 · Aug 22, 2011

Great instructions. I have some of these bands on the way and will be trying them out.

Cheers ..... Charles

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Charles

· #116 · Aug 26, 2011

I just put a pair of 105s on a PFS and fired off about 50 shots with .44 caliber (11 mm) lead. I was very pleased with the results. I am anxious to try the "tapered" concept with the 107s, but haven't gotten to that yet. For the money, these bands are very hard to beat.

When I was a young boy, I lived for a while in east Texas (Kilgore) ... sometime in the 1950s. I used to buy large rubber bands from a local stationary store. In those days, there were many oil derriks around town. Even as a boy, I could use those bands to chuck a one inch diameter rock over an oil derrick from at least 50 yards away. These Sterlings sort of remind me of those bands I used as a kid.

Cheers ....... Charles

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Charles

· #187 · Oct 25, 2011

HopefulHunter said:
Hello all, sorry to hijack this for advertising, but i need as many people as I can get to know about this. I've gotten in touch with Alliance regarding bringing a shipment of bands into the UK, the minimum order is 40 boxes

But I've asked for prices anyway and with a bit of luck they'll be fairly cheap as they're coming directly from the source. Anyone in UK or Europe who is interested please let me know as I'd like to account for about 30 boxes from other people before I could even consider this

http://slingshotforu...__fromsearch__1

I'd not be selling these for any kind of profit, just to help people in this country and nearby get their hands on some.

Cheers all.

Eddie.

Say, Eddie,

You know you can buy them a box at a time from Amazon in the UK

http://www.amazon.co.uk/Alliance-Sterling-Ergonomically-Correct-Rubber/dp/B005HGDOKK/ref=sr_1_6?s=officeproduct&ie=UTF8&qid=1319573236&sr=1-6

Cheers ........ Charles

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Charles

· #217 · May 13, 2013

boby said:
Since the speed of sound (~ 1000 ft/s) is not huge compared to projectile speeds ( ~ 200 ft/s), there can be some error introduced in the Audacity method (e.g., 20%). This error can be reduced to 0% if the microphone is positioned exactly midway between the 2 sound sources (card & catch box fabric). If I follow Henry's setup correctly, I think his inferred speeds are low by ~ 20%. Also, does anyone know how much the index card (or a sheet of tissue or ??) slows down the projectile? Everyone seems to ignore this, but I wonder if it really is negligible. This would also underestimate the speed.

If you check the thread giving the accepted method on this forum for the Android app, you will find it clearly stated that the phone must be placed half way between the two sound producers.

http://slingshotforum.com/topic/21084-smartphone-chrony-setup-tutorial/

Cheers ..... Charles

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Charles

· #218 · May 15, 2013

boby said:
Also, does anyone know how much the index card (or a sheet of tissue or ??) slows down the projectile? Everyone seems to ignore this, but I wonder if it really is negligible. This would also underestimate the speed.

I just conducted an empirical test. I clipped a sheet of newsprint over a hole in a cardboard box. I fired a series of 5 shots, each through a different part of the paper. Each shot went through one and only one layer of newsprint. I used a chrony to determine the velocity. I was using 3/8 inch steel ball.

The mean velocity through the paper was 167.2 fps, with a standard deviation of 1.88944.

I removed the paper and then fired five shots through the hole in the box, again over the chrony. Again I was using a 3/8 inch steel ball.

The mean velocity without the paper was 164.98, with a standard deviation of 4.1607.

These shots were all fired by hand, using the same slingshot, from the same point in front of the target, as they would be in both the Speed Freaks and the Power Rangers competitions. It is abundantly clear that individual variations shot to shot completely outweigh any minimal effect due to firing through one layer of newsprint. In these competitions, any effect on velocity from shooting through a sheet of newsprint is indeed negligible.

Cheers ...... Charles

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Charles

· #227 · Sep 4, 2013

Protect them from light and from atmosphere. Put them in a zip lock bag and keep them in a dark place ... a cookie tin works well.

Cheers ...... Charles

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Charles

· #229 · Sep 4, 2013

ZorroSlinger said:
When one starts out in slingshot sport, the bug can hit with buying spree without careful thought. I got box of 107s and in combination with other elastics material, more than what I can use! The 107s, I use least compared to other elastics. Maybe I will taper the the 107s and see if the more snappy performance is more incentive to use them.

The 107s too durable ... I actually want them to tear & break so I can use them up! My shooting practice has mostly been light ammo for plinking and also PFS/small shooters. The107s at 5/8" wide x .062" thick, too heavy for what I need. I am thinking of and maybe attempt to slit the 5/8" wide bands down the middle, making two 5/16" wide strips for lighter shooting purposes. I can see possible difficulty of making exact center cuts. May require some kind of jig or special set-up to make precise center cutting of the 107s. Jeez ... more work

Tapering 107s or 105s is an easy thing to do, and it will give you an increase in velocity at the expense of band life.

http://slingshotforum.com/topic/11038-taper-by-cutting/

I just use a straight edge and roller cutter. If you do not have a roller cutter, just wash the bands and dry them well to remove all talc. Then put masking tape on one (or both) sides. Measure out your taper and cut carefully with a pair of scissors. You could do the same for center cuts.

Cheers ..... Charles

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Charles

· #238 · Feb 9, 2014

Hand slap is generally the result of using ammo too light for the power of your bands. Use weaker bands or heavier ammo. That way there is less residual energy left in the pouch to come back and hit your hand.

Cheers ......... Charles

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Charles

· #252 · May 2, 2014

In fact, with a slightly different arrangement (1/3 triple, 1/3 double, 1/3 single) I did even better:

http://slingshotforum.com/topic/21108-power-rangers/?p=276694

Certainly one could use Theraband Gold and get more power. But I just wanted to see what was possible using good old Alliance Sterling 107s. With proper set up, these bands are capable of great power.

Henry is absolutely right ... they are cheap and generally available ... they make good, all purpose bands.

Cheers ..... Chales

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Charles

· #254 · May 3, 2014

Henry in Panama said:
I knew you had bested that, Charles, but I was short of time and just posted the first I found.

No problem, Henry. It has gotten to be a beast to sort through that thread and find any specific post!

I like my Alliance bands. For just mucking about, they are very hard to beat. I should also point out that they have very good resistance to deterioration, quite unlike pure latex.

Cheers ..... Charles

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